UK PHOCINE DISTEMPER VIRUS EPIZOOTIC
INVESTIGATION REPORT 2002/2003
Final Report
Conducted for the Department for Environment, Food and Rural Affairs (Defra)
Collaborative investigation co-ordinated by the
Institute of Zoology The Zoological Society of London Regent’s Park London NW1 4RY England
Compiled by: Becki Lawson MA VetMB MSc MRCVS Paul D. Jepson BVMS PhD MRCVS
Contract start date: 13th August 2002 Contract end date: 31st August 2003
Phocine Distemper Virus Epizootic Investigation 2002/2003 Phocine Distemper Virus Epizootic Investigation 2002/2003 2 Contents
• Preface 5 • Executive Summary 6 • Introduction 7 • Overview of Morbilliviruses in Marine Mammals 7 • Aim of Investigation 11 • Objectives of the Investigation 11 • Materials and Methods 12 Project Organisation and Response Plan 12 Opportunistic Reporting of Dead Seals 12 Systematic Reporting of Dead Seals 13 Data Recording 15 Pathological Investigations 16 Serological Investigations (Feline herpesvirus/Toxoplasma) 19 Carcass Disposal 20 Information Distribution 21 Aerial Census Surveys and Population Estimates 22 Quantification of Regional Seal Mortality 23 • Results 24 Monitoring of UK seal mortality 24 Pathological Investigations 27 Patterns of PDV exposure in UK seals 32 Patterns of UK Seal Mortality 36 Quantification of Seal Mortality (Aerial Survey) 40 Comparative epidemiology of 1988 and 2002 PDV epizootics 43 Opportunistic Reporting of Dead Seals (National Seal Hotline) 46 Systematic Reporting of Dead Seals 46 Information Distribution and Media Management 48 • Discussion 51 Epidemiology of the 2002 UK PDV Epizootic 52 Comparison of the 1988 and 2002 PDV Epizootic Epidemiology 53 Pathological Investigations 54 Molecular Diagnostic Testing 56 Opportunistic Reporting 56 Systematic Reporting 57 Carcass Disposal 58 • Recommendations for the Investigation of Future Wildlife Epizootics 60 • Investigation Outputs 62 • Parallel Research 62 • Future Research 62 • Cited References/Bibliography 64 • Appendices 1. Organisation Contact Directory 1.1 Collaborators and Participating Organisations 1.2 Other Related Organisations 1.3 English Local Authority Details 2. Defra Website Information
Phocine Distemper Virus Epizootic Investigation 2002/2003 3 2.1 Defra News Release 2.2 Seals and Phocine Distemper Virus (PDV) 2.3 Suggested Disposal Options for Seal Carcasses 2.4 Do you own land on the coast? Letter providing guidelines to private landowners along the coast 2.5 Frequently asked questions about Phocine Distemper Virus 2.6 Options for a vaccination program 2.8 Public health guidance note issued by the Scottish Centre for Inspection and Environmental Health 3. Volunteer Guidelines 4. Post mortem examination protocol and report pro forma 5. Media and Information Dissemination 5.1 Zoology Society of London Press Release 5.2 - 5.3 Zoological Society of London Interview and Coverage Log 5.4 Greenland Interactive National Seal Hotline Call Log 5.5 Example of UK PDV Status Report 6. Images 7. Systematic Reporting - Volunteer Appeal Appraisal
Phocine Distemper Virus Epizootic Investigation 2002/2003 4 • Preface
Following the re-emergence of phocine distemper virus (PDV) in European common seals (Phoca vitulina) in May 2002, it was evident that a pan-European outbreak of the same viral disease that killed approximately 18,000 seals in 1988 was likely to re-occur. The devastating consequences of the 1988 epizootic resulted in one of the largest and most high profile epizootics affecting indigenous wildlife species in the UK. In August 2002 the UK Government (Defra) elected to fund a large-scale national collaborative research project. The principal aims of the investigation were to investigate the impact of the 2002 PDV epizootic on UK seal populations, advise Government on the most appropriate response to the disease outbreak, and to rapidly disseminate information to all interested parties including the general public. Organisation of the investigation involved liaison between governmental bodies, research and academic institutions, local authorities, animal rescue charities, non-governmental organisations, commercial groups and members of the public. The co-ordination of this multidisciplinary project relied on close and continual collaboration between all parties.
A preliminary report, submitted to Defra in September 2003, gave particular emphasis to the methodology and management of the investigation coupled with an appraisal of its successes and limitations to date. Information on lessons learnt will be of use for investigation of future disease outbreaks affecting marine mammals and other free-ranging wildlife species. This final version of this report also incorporates a review of morbilliviruses in marine mammals, the full suite of diagnostic and histopathological test results from the investigation, and population estimates derived from aerial census surveys enabling the most accurate predictions of the impact of the 2002 PDV epizootic on UK common and grey seal (Halichoerus grypus) populations.
Phocine Distemper Virus Epizootic Investigation 2002/2003 5 • Executive Summary
Approximately 18,000 common seals (Phoca vitulina) and 500 grey seals (Halichoerus grypus) died during the 1988 European phocine distemper virus (PDV) epizootic. Most seal populations subsequently recovered to pre-epizootic levels. In May 2002 a second European PDV epizootic began on Anholt Island in the Kattegat, the same location where the 1988 epizootic was initiated. In August 2002, following the spread of the epizootic into the North Sea and Waddensea, the UK Government funded a national collaborative research project to investigate the impact of the PDV epizootic on UK seal populations. Shortly afterwards the first case of PDV infection in the UK was confirmed in a common seal, examined by RSPCA veterinarians, that had been found in The Wash in July 2002.
Reports of dead seals were obtained opportunistically through a National Seal Hotline telephone number, from Local Authorities and via a network of volunteers systematically monitoring stretches of UK coastline. This enabled the identification of spatial and temporal trends in seal mortality. The National Seal Hotline also forwarded any reports of sick live seals to the RSPCA and Scottish SPCA. Seal carcasses were retrieved or examined in situ using standardised necropsy techniques to monitor the spread of the virus and to facilitate the archiving of tissue samples for research purposes. PDV infection was confirmed by specialist laboratories using reverse-transcriptase polymerase chain reaction (RT-PCR) and/or immunohistochemistry. Weekly Status Reports were collated and posted on the Sea Mammal Research Unit (SMRU) website, and a recorded message was hosted on the National Seal Hotline, enabling the latest information on seal strandings and post mortem investigation results to be rapidly placed within the public domain.
Epizootic common seal mortality increased rapidly within The Wash to reach a peak in mid-September followed by a gradual decline to background levels of mortality by November/December 2002. Molecular testing confirmed PDV infection in 69/77 (90%) of common seals examined from The Wash between July and October inclusive, most of which had gross and microscopic lesions consistent with fatal phocine distemper. Pre and post-epizootic aerial surveys indicated that 13-18% of The Wash common seal population died; significantly lower than during the 1988 PDV epizootic. Based on carcass counts and aerial survey data there was no perceptible increase in common or grey seal mortality in Scotland, Wales or Northern Ireland. PDV infection was confirmed in 12/27 (44%) of common and 9/42 (21%) of grey seals in Scotland examined between September 2002 and January 2003, but only 6 common seals from Scotland were diagnosed to have died due to phocine distemper. Two cases of PDV infection were confirmed in seals from Northern Ireland but no cases were reported from colonies in Wales, Shetland or Cornwall. No cases of fatal distemper were diagnosed in any UK grey seals. Concerns that PDV could over- winter in UK seals and induce subsequent epizootic-type mortality in Scottish common seals in the summer of 2003 during periods of high seal haul-out density proved unfounded. Reasons for the lower common seal mortality rates in Scotland are incompletely understood, although epidemiological factors such as lower seal haul-out densities during periods of viral exposure, lower pollutant levels, and increased genetic resistance due to historical PDV exposure have been suggested. Epidemiological modelling incorporating movement probabilities between colonies may assist in addressing these uncertainties and in predicting the frequencies and impacts of future PDV epizootics on European seal populations.
Phocine Distemper Virus Epizootic Investigation 2002/2003 6 • Introduction
During 1988 a major epizootic of phocine distemper caused the death of approximately 18,000 common, or harbour, seals (Phoca vitulina) and 500 grey seals (Halichoerus grypus) in European waters. The epizootic, caused by phocine distemper virus (PDV), began in the Kattegat and spread over several months to infect seals in the Baltic, Waddensea, North Sea and Irish Sea. Considerable scientific research was conducted in 1988-1989 in the UK and in other parts of Europe to initially identify the cause of the 1988 die-off and to assess the epidemiological impact of the PDV epizootic on UK and European seals. Within the UK, the greatest declines in common seal populations occurred in The Wash and, to a lesser degree, in the Moray Firth.
During May - July 2002 a virus virtually identical to the 1988 strain of PDV was associated with epizootic common seal mortality in the Kattegat and Waddensea areas. As the epizootic progressed, it was realised that there was a high probability that the 2002 European PDV epizootic would again reach UK shores posing a number of important scientific and logistical challenges. These included the need to assess the impact of PDV on UK seal populations, to identify which seal colonies were most affected by PDV, and to investigate the role potential contributory factors may have on the susceptibility to and pathogenicity of PDV in UK seals. There was also a key requirement for the rapid dissemination of information in order to keep Government, media and general public appraised of these developments. The resultant collaborative research investigation was initiated and funded by Defra in August 2002 with the remit to address these key areas.
• Overview of Morbilliviruses in Marine Mammals
The past 15 years have witnessed the emergence of several newly recognized members of the Morbillivirus genus as significant causes of disease outbreaks and mortality in marine mammals belonging to the orders Pinnipedia (seals) and Cetacea (whales, porpoises and dolphins). The first morbillivirus with potentially severe ecological consequences for marine mammals was identified in common (Phoca vitulina) and grey (Halichoerus grypus) seals which died in large numbers off the coasts of northern Europe in 1988 (Osterhaus & Vedder, 1988). At first, based on clinical and antigenic similarities, the seal virus was thought to be canine distemper virus (CDV), the main pathological feature being acute pneumonia. The interest which resulted from finding a morbillivirus in marine mammals for the first time meant that all available resources were quickly employed to characterise the new virus. These analyses soon showed that the seal virus was most closely related to, but distinct from, CDV and was classified as a new member of the morbillivirus genus and named Phocine distemper virus (PDV). The most severely affected species was the harbour seal, also known as the common seal, from the North Sea and north-western Atlantic with grey seals from the same areas proving more resistant to the virus. Since then three other morbilliviruses have been found to infect various species of marine mammals: CDV itself has been found in seals and polar bears, a morbillivirus (PMV) has been isolated from porpoises and another from dolphins (DMV) (McCullough et al., 1991; Visser et al., 1993). The latter two viruses are genetically very closely related (Barrett et al., 1993) but they are not species-specific as the porpoise virus has been found in dolphins (Taubenberger et al., 1996). They are best regarded as variants of a cetacean morbillivirus (CeMV). Many cetacean species world-wide have been reported to be
Phocine Distemper Virus Epizootic Investigation 2002/2003 7 seropositive for this virus (Van Bressem et al., 2000). The pilot whale (Globicephala spp.) appears to be the reservoir and vector for transmission of the CeMV to other species as they move in large groups, known as pods, over great ocean distances and have a world- wide distribution. Over 90% of pilot whales that were involved in mass strandings between 1982 and 1993 were morbillivirus seropositive (Duignan et al., 1995).
Apart from PDV infections, other morbilliviruses can also cause mortality in seal populations. In the winter of 1987-1988, just prior to the European seal epizootic, Lake Baikal seals (Phoca sibirica) suffered an unusual and severe mortality. Subsequently CDV, rather than PDV, was shown to have been the aetiological agent for that event (Grachev et al., 1989; Visser et al., 1990). Similarly, a mass die off that occurred in Caspian Sea seals (Phoca caspica) in 1997, and again in 2000, was also attributed to CDV infection (Forsyth et al., 1998; Kennedy et al., 2000). Although not proven, the source of the virus is likely to have been terrestrial carnivores, such as wolves, which prey on seal pups. Retrospective serological evidence also links this virus with deaths of thousands of crabeater (Lobodon carcinophagus) seals near a base with sledge dogs in the Antarctic in the 1950s. Since there are no terrestrial carnivores in the Antarctic it is likely that sledge dogs used at that time were the original source of CDV, or possibly the animals were infected by contact with carnivores in New Zealand or South America during migrations. The virus appears to have established itself in the crabeater seal population as a subsequent serological survey of Antarctic seals showed them to have a high prevalence of CDV- specific antibodies (Bengtson et al., 1991).
When wildlife species show clinical disease with signs resembling distemper, a morbillivirus infection may be involved. As CDV and PDV infections in seals are clinically similar, differential diagnosis has to be made between these two diseases and this is most easily done by RT-PCR using universal morbillivirus primer sets and primer sets specific for each morbillivirus species. Some evidence also links the cetacean morbillivirus with seal mortality, although not on the same massive scale seen with PDV or CDV. The rare monk seal population of the eastern Mediterranean was not severely affected during an epizootic of this virus which killed thousands of striped dolphins (Stenella coeruleoalba) around the Mediterranean coasts in 1990-1991, however, the cetacean morbillivirus was found in carcasses of monk seals that died in large numbers off the coast of Mauritania in 1997 (Van de Bildt et al., 2000). At the time an algal bloom was also considered to be an exacerbating or primary factor which may have contributed to the very high mortality among adult seals at that time (Harwood, 1998; Hernandez et al., 1998).
Until 2002 the most devastating virus-induced mass mortality event in European seals occurred in 1988, when PDV killed more than 18,000 seals around northern European coasts, the vast majority being common seals. That epizootic began on the Danish island of Anholt in the Kattegat and then spread to Sweden, the Netherlands, Norway, Germany, the UK and Ireland. Since 1989 there has been no convincing serological evidence for persistence of PDV in European seals (Thompson et al., 2002). A minor outbreak of disease in seals occurred in 1998 along the Belgian and northern French coasts and morbillivirus antigen and nucleid acid were detected in tissues from sick animals. However, most of the viruses involved were genetically closely related to either CeMV or CDV (Jauniaux et al., 1998; El Mjiyad et al., 2003).
Phocine Distemper Virus Epizootic Investigation 2002/2003 8 Unfortunately, in 2002 a major European PDV epizootic recurred, again mainly affecting common seals. The epizootic followed an almost identical course to that of 1988, starting at the end of April again originating from the island of Anholt (population ~ 12,000 common seals). Through May the virus spread from the initial focus in the Kattegat through the Skagerrak and then into the Dutch Wadden Sea and the North Sea.
The small size and scattered nature of European seal populations makes it unlikely that they could maintain this virus in circulation as morbilliviruses need a constant supply of new susceptible hosts since, following recovery, infection induces life-long immunity to the virus. The curious course of the epizootic on both occasions (1988 and 2002), starting from the Danish coast, moving first to the Dutch and then on to English coasts and finally ending in Scotland, may be explained by the migratory and breeding habits of the seals. There is growing consensus among some seal biologists that grey seals may be key vectors in the transmission of PDV between common seal colonies in European waters, especially where large geographical jumps are made. Common seals usually return to the same haul- out whereas grey seals do not and move much greater distances between haul-out sites (McConnell et al., 1999). Since it is likely that most virus transmission occurs on land, their mixing haul-out sites may be the key factor. Another may be the relative resistance of this species to the virus enabling it to transmit without necessarily showing severe clinical disease.
The most likely source of the original infection for the European seals was contact with seal species from the Arctic. This has been proposed on the grounds that morbillivirus, and more specifically PDV antibodies, were found in archival sera obtained from Arctic seals long before the first known European outbreak in 1988 (Henderson et al., 1992; Ross et al., 1992). Arctic harp seals (Phoca groenlandica) were noticed to have migrated much further south to reach northern European waters in the year prior to the epizootic, probably as a result of climatic changes and overfishing around Greenland (Dietz et al., 1989). One possible scenario is that harp seals, at least in 1988, infected grey seals, which then introduced the virus into common seals at Anholt. Grey seals are known to haul-out in small numbers in Anholt alongside the large common seal population there. This may explain why both 1988 and 2002 epizootics started on Anholt. The full host range of PDV has not been fully determined but it can infect many species of seal (Duignan et al., 1997). The harp seal population is extremely large, with an estimated four million individuals in Canadian waters alone, and is sufficient to maintain PDV in circulation.
Control of wildlife diseases is extremely difficult and vaccination of wild animal populations, which in any case is logistically very problematic, would also raise ethical questions concerning uncontrolled spread of the vaccine virus. Protection of vulnerable animals in seal sanctuaries would be acceptable as the animals could be confined until the excretion of any vaccine virus had ceased. In any event, there is no currently licensed vaccine for use in seals. Because of the close antigenic relationship between morbilliviruses, strong cross-protection to infection is given by vaccines for other morbilliviruses and an experimental CDV-ISCOM vaccine has been shown to protect seals from PDV but the duration of the immunity induced remains uncertain (Visser et al., 1992). This, and also a live attenuated vaccine that is used to protect dogs from CDV, could also be used to protect seals in sanctuaries during virus epizootics. However, there are no commercial sources of the CDV-ISCOM vaccine and the commercially available CDV vaccines have not been tested for safety in seals and these vaccines have been shown to cause death in some wild species (Carpenter et al., 1976). Following the 1988 epizootic
Phocine Distemper Virus Epizootic Investigation 2002/2003 9 the affected seal populations recovered their normal (pre 1998) population levels within a few years and, it is hoped, the same will happen this time round.
See Bibliography for contemporary list of PDV and other marine mammal morbillivirus- related publications.
Phocine Distemper Virus Epizootic Investigation 2002/2003 10 • Aim of Investigation
To investigate the impact of the phocine distemper virus epizootic 2002/2003 on UK seal populations.
• Objectives of the Investigation
Objective 1: Opportunistic monitoring of dead seal reports collected through the National Seal Hotline.
Objective 2: Systematic monitoring of coastline for evidence of seal mortality by recruited volunteer network.
Objective 3: Post mortem examination of seal carcasses around the UK following standardised protocols.
Objective 4: Use of molecular diagnostic testing for confirmation of the presence of PDV infection.
Objective 5: Estimation of pre- and post-epizootic common and grey seal populations through aerial census surveys.
Objective 6: Dissemination of up-to-date information on the PDV epizootic to the public and media.
Objective 7: Provide advice to Government on the most appropriate response strategies to the emerging UK phocine distemper outbreak.
Details of the key collaborating institutions for the investigation are included in Appendix 1.1.
Timetable: The collaborative research project co-ordinated by the Institute of Zoology, London, ran from the 13th August 2002 until 31st August 2003.
Phocine Distemper Virus Epizootic Investigation 2002/2003 11 • Materials and Methods
Project Organisation and Response Plan
A scheme was devised for the reporting and recording of live sick and dead seals affected during the PDV epizootic. The scheme outlines responsibility for appropriate action in each scenario. A decision-making tree (See Appendix 2.1) was constructed with a series of questions to guide the user to the organisation able to deal with their query. Contact details for each group were provided within the flow diagram and this was made available from the outset of the PDV epizootic in the UK on the Defra website (http://www.defra.gov.uk).
The Sea Mammal Research Unit (SMRU) was the main responder to the first major phocine distemper outbreak among UK common (Phoca vitulina) and grey (Halichoerus grypus) seals in 1988 (Hall et al., 1992). It was therefore able to provide detailed information on where carcasses were recovered during this previous epizootic so that resources during the 2002 outbreak could be directed to the most likely locations, given the spatial similarity between the two outbreaks (e.g southeast England, particularly the coast of Norfolk, Suffolk and Essex). A copy of the complete 1988 SMRU database was sent to the co-ordinators of the response to the 2002 outbreak in England and Scotland (the Institute of Zoology and the Scottish Agricultural College (SAC), Inverness). Arcview GIS generated maps, showing the locations and numbers of animals found, were also created by SMRU and distributed for reference purposes.
Opportunistic Reporting of Dead Seals
Telephone Reporting
The National Seal Hotline came into operation on August 13, 2002 and was publicised with a press release issued by Defra (see Appendix 2.1). The single hotline number (T: 08712 447 999) for the UK provided straightforward access to a number of reporting options through an automated system. The phone line system was organised and operated by Greenland Interactive Limited.
Live sick seals
Callers with details of live sick seals in urgent need of attention were instructed to contact the RSPCA or Scottish SPCA as appropriate dependent on region. Operators on the 24- hour RSPCA Emergency Hotline were available to field these calls and collect relevant details. The inspectorate of the regional animal welfare organisation investigated reported cases. Members of the British Divers Marine Life Rescue organisation also assisted the RSPCA with this work. Where intervention was indicated on the basis of a number of factors, decisions would be made as to whether seals were taken into care for the purpose of rehabilitation or euthanased in the field. Rehabilitation centres vary in capacity and policy in the event of an outbreak of infectious disease. The RSPCA Norfolk Wildlife Hospital is the largest specialist facility for the treatment and rehabilitation of seals in England and is located close to the large common seal population in The Wash. Funding and resources for seal rescue and rehabilitation were not included as part of this contract.
Phocine Distemper Virus Epizootic Investigation 2002/2003 12 Dead seals
Callers wishing to report details of dead seals were automatically diverted to national co- ordinators (England: Institute of Zoology; Scotland: SAC Inverness; Wales: Marine Environmental Monitoring; Northern Ireland: Quoile Countryside Centre). Callers were requested to leave their name and telephone contact number along with details of the date, exact location and number of seals found. The message clearly explained that in order to assist with carcass disposal as quickly and effectively as possible, their name and contact details may be passed to the department of the Local Authority responsible for carcass disposal. Callers were requested to state if they did not wish their details to be passed on to a third party in accordance with the Data Protection Act 1998.
Due to the large volume of phone calls during the PDV epizootic in England, reports were logged through an answer phone service. Two machines with long tape memory were purchased to ensure capacity to deal with peak caller demand. Messages were checked regularly throughout each day and transcribed into the UK Seal Strandings Database. Similarly in Wales, calls were logged by answer phone and interrogated at regular intervals. In Scotland, SAC Inverness staff involved in the PDV investigation answered all calls reporting seals during office hours. An answer machine was used at the weekend for logging calls and the mobile phone numbers of staff were made available for members of the public to report direct out of hours.
The National Seal Hotline remained in full operation until March 13th 2003. From that date, the system was simplified from the automatic diverting system to a single message with details of the telephone numbers for contact organisations. This arrangement enabled continued monitoring of seal mortality through the same telephone contact number at a negotiated fee. Operation of the hotline in this format helped to maintain the compliance and ease of reporting for callers familiar with the telephone number and enabled collection of data with a comparable intensity of effort throughout the project.
Electronic Reporting
A dedicated e-mail account was used by each national co-ordinator for the project that provided an electronic means for reporting of dead seal sightings. (England: [email protected]; Northern Ireland: [email protected]; Scotland: [email protected]; Wales: [email protected]).
Systematic Reporting of Dead Seals
Volunteer Recruitment
An appeal for volunteer assistance with systematic coastal surveys was made in England, Scotland and Wales. In Northern Ireland, an existing network of individuals was able to follow up on dead seal reports, visiting the coast to examine all accessible carcasses, thereby providing high “quality” data. Consequently no similar volunteer scheme was instigated in the response plan for Northern Ireland. The volunteer appeal was made with the two-fold aim of 1. increasing the “quality” of dead seal reports (e.g. species identification, body length measurements) and 2. providing a systematic reporting scheme
Phocine Distemper Virus Epizootic Investigation 2002/2003 13 that would enable documentation of “negative sightings” data (i.e. stretches of beach which were surveyed on specified dates where no evidence of seal mortality was observed).
The appeal for volunteers in the UK occurred in three stages. In the first instance, specific marine groups, animal rescue related organisations and other parties likely to become directly involved were contacted. It was anticipated that members of these groups would be most likely to respond and participate in the systematic surveying following a scientific methodology. The second phase included dissemination of the volunteer guidelines to a wide range of UK based wildlife related organisations (See Appendix 1.2). Following these appeals for assistance, the decision was made to progress to a general press release to members of the public, targeting local coastal press in areas where volunteer assistance was sought. This appeal was organised in collaboration with the Zoological Society of London (ZSL) Public Relations department (See Appendix 5.1).
Within Wales, an established network of volunteers already exists as part of the “Collaborative UK Marine Mammal and Turtle Strandings Project” and many of these people assisted during the PDV outbreak. The appeal for new volunteers in England was terminated at the end of October (25/10/2002) when it was clear that the peak of the epizootic was over. All subsequent contacts in England were requested to continue to use the National Seal Hotline as opportunistic reporters. The appeal for volunteers in Scotland and Wales remained open throughout the investigation.
Volunteer Scheme
Volunteers were asked to survey the same local area of coastline on a once or twice weekly basis looking for evidence of dead seals. Survey areas were requested in increments of single kilometre stretches. Guidelines were produced that included detailed information on seal species identification and the key morphological features for discrimination of common and grey seals. Instructions were provided for taking of standard body length measurements and a subjective method of estimating degree of carcass decomposition was included. Volunteers willing to take images of dead seals were encouraged to send electronic or hard copy photographs to their national co-ordinator for collation.
The guidelines included a Health and Safety section with advice on selection of safe areas of coastline to survey, weather and tide conditions, etc. Members of the public were advised not to touch or attempt to move carcasses in any way as part of their survey but to record all results strictly through observation only (See Appendix 3). Consequently, no consistent method of carcass marking (e.g. flipper tagging) that required contact with the carcass was possible through the scheme.
A tailored set of guidelines was produced for British Divers Marine Life Rescue (BDMLR) members. Members of this organisation receive Marine Mammal Medic training with certification of course attendance and are covered by personal liability insurance for the potential hazards involved with the rescue of live sick marine mammals or handling of carcasses. Supplies of protective disposable gloves were offered to all BDMLR volunteers for carcass handling. Yellow plastic flipper tags were also made available to BDMLR volunteers to enable clear carcass marking. Marking was preferred, where possible, since identification of individual carcasses would reduce the likelihood of duplication of dead seal reports.
Phocine Distemper Virus Epizootic Investigation 2002/2003 14 Following an initial contact expressing interest in assisting with the scheme, copies of the appropriate guidelines and Microsoft Excel reporting template were distributed by e- mail, fax or post. Each individual volunteer was issued with a unique reference number. Volunteers were also given information about the free access Ordnance Survey (OS) “Get-a-Map” Website (http://www.getamap.co.uk) enabling them to identify the grid references for their survey area.
Each national co-ordinator mapped proposed volunteer survey areas in an effort to minimise duplication of effort through overlapping survey areas and the increase in likelihood of duplicate reports that could result. Volunteer reports could be made by e- mail, telephone, fax or post to each national co-ordinator. A Microsoft Excel volunteer survey pro forma was created for simple and convenient reporting of data. It was requested that reports be passed to the national co-ordinator on a regular weekly basis to allow integration of information as the epizootic progressed.
In England, the decision was made to close the systematic volunteer scheme in early December (06/12/2002). At this stage, the epizootic had reached its tail and the number of dead seal reports by members of the public and volunteers were at a low level. All volunteers were asked to continue to report any further sightings of dead seals via the National Seal Hotline. As far as possible, volunteers were contacted personally by telephone or e-mail in order to thank them for their assistance. This also provided a useful opportunity to identify volunteers who had been active with survey work but whom had not reported dates and locations for “negative survey” work. A similar approach was adopted with the Welsh team of volunteers. Scottish volunteers were sent a final letter that, in addition to thanking them for their assistance, contained summary information on the PDV epizootic in their area and included a pre-paid envelope for reporting of outstanding survey reports. In Wales and Scotland, volunteer reports were collected throughout the full six months of the early project period. After the end of the outbreak a number of the SAC Scottish volunteers were happy to continue surveying the stretches of coastline they had been allocated during the outbreak. SMRU then took over collating the reports from these volunteers, which acted as an early warning network, in case a secondary outbreak was to occur in Spring 2003. This scheme finished at the end of the summer 2003 when a Newsletter was sent to all those participating, thanking them for their help and summarizing the findings.
Data Recording
UK Seal Strandings Database
All dead seal reports for the UK during the period of the project were assigned a unique reference code in sequential numerical order according to when seal reports were received. A prefix code was used to indicate the country where the seal was found (England: E- PDV-0001…E-PDV-000n; Northern Ireland: NI-PDV-0001…NI-PDV-000n; Scotland: S- PDV-0001…S-PDV-000n; Wales: W-PDV-0001…W-PDV-000n). The use of “PDV” in these index systems indicated inclusion of the seal within the PDV project and not that PDV infection had been positively confirmed in that animal. For each dead seal report, available case details were entered into the database using a number of standardised data fields. Dead seal reports recorded through both opportunistic and systematic reporting methods were integrated in a single UK Seal Strandings Database. The UK Seal Strandings
Phocine Distemper Virus Epizootic Investigation 2002/2003 15 Database will be available as an electronic resource for consultation following publication of the final report.
Detailed grid references for the exact location of the seal carcass were used when supplied by the reporter although this information was only available in the minority of cases. In the absence of an exact location, the closest possible grid references were assigned on an individual basis. To help allocate and verify grid reference information Ordnance Survey (OS) Landranger Maps (1:50,000), the OS Interactive Atlas of Great Britain (5th edition) and the OS “Get-a-Map” website (http://www.getamap.co.uk) were used.
Seals that were taken into rehabilitation and died, or were euthanased, within seven days of admission were included within the project data set. Details of seals that died, or were euthanased, in rehabilitation after a period of more than one week were recorded but excluded from analysis.
Volunteer Report Database
Systematic survey volunteer reports were collected and transcribed into a regional volunteer database by each national co-ordinator. Information on all “positive sightings” during surveys was entered into the volunteer database and replicated in the main UK Seal Strandings Database to ensure that all information on dead seal reports was fully integrated. Information on “negative sightings” was included in the regional volunteer database with details of the date and area surveyed. OS map grid reference information and data fields were determined as for the main database. The volunteer databases will be available as an electronic resource for consultation following the final report.
Focal Area Reports
A number of wardens and land managers provided diaries of dead seals found within the area of coastline for which they were responsible during the PDV epizootic. Detailed information on the species and approximate size of the carcasses was often included. An assessment was made on an individual basis of the likelihood for duplication of reports from these databases with reports received through the National Seal Hotline and volunteer networks. A conservative approach was adopted with incorporation of reports considered unlikely to represent duplicate reports into the UK Seal Strandings Database.
A pre-existing strandings report scheme for cetaceans and seals operates around the Cornish coastline under the direction of the Cornwall Wildlife Trust. Dead seal reports for the South West of England were co-ordinated by this scheme and included within the UK Seal Strandings Database.
Pathological Investigations
Fresh carcasses in accessible locations were identified and retrieved for post mortem examination where possible. In England, the Natural History Museum was contracted for collection and delivery of seal carcasses. Additional assistance was given by the Peaceful Pets crematorium and E-Van Deliveries Ltd. Marine Environmental Monitoring, Quoile Countryside Centre, SAC Inverness and SMRU organised inspection of carcasses reported to be in fresh or slightly decomposed condition in Wales, Northern Ireland and Scotland
Phocine Distemper Virus Epizootic Investigation 2002/2003 16 respectively, and arranged transportation of bodies suitable for post mortem examination. SMRU also assisted the Scottish response by collecting samples for diagnostic testing from seals where the carcasses were too decomposed for full post mortem examination or were located in an irretrievable position (e.g. at the base of steep cliffs) along the coast of Fife.
In England, the majority of post mortem examinations were performed at pathology facilities at the Institute of Zoology. To facilitate examination of as many carcasses as possible during the peak of the epizootic, a temporary cold store facility was used to hold large numbers of refrigerated carcasses at the Peaceful Pets Crematorium, Norfolk. The staff at the centre organised carcass reception on delivery and dealt with disposal following post mortem examination using on-site incineration. Seals that died in rehabilitation at the RSPCA Norfolk Wildlife Hospital were examined by the resident veterinary surgeons or transported to the Institute of Zoology for necropsy. Information from post mortem examination of seals that died or were euthanased after less than, or equal to, one week in captivity were included within the pathology data set.
The pathology departments at Cambridge Veterinary School and the Royal Veterinary College, London, assisted with the post mortem examination work. Post-graduate veterinary students studying on the MSc in Wild Animal Health also performed a small number of necropsies. In rare instances, veterinary surgeons in private practice performed post mortem examinations and collected tissue samples for diagnostic testing.
Necropsy protocols
Post mortem examinations were performed according to a standardised protocol (see Appendix 4). Post mortem examination forms were forwarded to pathologists to ensure comparable procedure was used in all cases as far as possible. Species, sex, body measurements and weight were recorded as routine. Standard samples were taken for virology, bacteriology, parasitology, histopathology, genetics, age determination, serology and toxicological investigations. Bacteriological examination consisted of a routine tissue sample or swab taken aseptically for aerobic and anaerobic bacteriological analyses and any organisms recovered were identified using conventional identification methods. Tissue samples for histological examination were preserved in neutral buffered 10% formalin, embedded in paraffin, sectioned at 2-6µm and stained with haematoxylin and eosin (H&E). Carcasses examined at post mortem were disposed of as clinical waste.
Age categories were used to examine the age structure of seal carcasses examined. For common seals, the first age category (pups) comprised sexually immature animals considered by the pathologist to be <1year old or had a head-hind flipper length ≤119cm. The second age category (juveniles) comprised sexually immature seals considered to be > 1 year old and/or had a head-hind flipper length ≥120cm. The third category (adults) was common seals considered to be sexually mature following necropsy. For grey seals, the first age category (pups) comprised sexually immature animals that had a head-hind flipper length ≤130cm. The second age category (juveniles) comprised sexually immature seals that had a head-hind flipper length >130cm. The third category (adults) was all grey seals considered to be sexually mature following necropsy.
A range of tissue and serum samples from seal necropsies were archived (along with tissues from stranded cetaceans) within the National Marine Mammal Tissue archive held at IOZ and SAC. These tissues will be available to support further PDV and non-PDV-
Phocine Distemper Virus Epizootic Investigation 2002/2003 17 related scientific research in the future. These tissue samples include histopathological sections, parasite specimens, serum samples, tissues for toxicological testing, teeth for ageing, and skin samples for genetic analyses (see Appendix 4).
Morbillivirus Immunohistochemistry (IPX)
Immunoperoxidase testing (IPX) of seals from all parts of the UK was performed at the Veterinary Sciences Division, Department of Agriculture and Rural Development, Northern Ireland (see Kennedy 1988, 1990). Sections of unstained sections from formalin fixed tissues (including lung, bladder, lymph node, kidney, thymus, spleen, heart, liver, adrenal) were stained using the streptavidin-biotin-peroxidase method. A monoclonal antibody to PDV was used. This antibody has been shown to be a broad screen for morbilliviruses with cross-reaction to canine distemper virus, cetacean morbillivirus (porpoise and dolphin) and measles virus. Tissue samples from a small number of common seals from The Wash were tested at the Department of Veterinary Pathology, Royal Veterinary College (London) using similar methods for morbillivirus detection.
Positive stain reactions on IPX were used to confirm presence of a morbillivirus and taken as evidence for a positive confirmation of PDV infection during the investigation. Immunohistochemistry testing demonstrates not only the presence of phocine distemper virus in the sample but also the distribution of virus within the tissue.
Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)
Samples of lung, bronchial lymph node, spleen and brain were taken for RT-PCR examination and stored at –70 degrees centigrade. Tests were performed at the Institute of Animal Health and the SMRU using the same methodology and primer sets. Couriers were used for transfer of samples on dry ice (-70oC) shipment to the laboratories.
Total RNA was extracted from the tissue samples for each seal. RNA quality was determined by denaturing agarose gel analysis. Up to 5 µg of RNA was transcribed into cDNA using M-MLV reverse transcriptase with random primers. The success of cDNA synthesis was analysed by PCR with gene specific β- actin primers. β- actin positive cDNA was then tested for the presence of PDV with two rounds of PCR. The first PCR was carried out using the general morbillivirus primers P1 and P2 (Barrett et al., 1993). This reaction was then used as a template for a heminested reaction using P1 in combination with a gene specific primer for PDV. This confirmed both the presence of PDV and overcame some problems associated with non-specific annealing of P1 and P2 in some of the samples. A subset of heminested PDV positive samples was sequenced to confirm the identity of the amplified product.
Positive reactions on any of the above tissue samples were taken to indicate the presence of PDV virus infection in that individual. Positive RT-PCR reactions demonstrate presence of genetic material from the PDV virus but cannot be used in isolation to determine whether the seal was suffering from clinical disease caused by the virus or was asymptomatically carrying the virus at the time of death. False negative reactions on RT-PCR testing can result if samples are degraded or if the seal was in an early stage of viraemia with little virus present to amplify at the time of death. Where sample condition did not permit sufficient genetic material to be extracted for examination, the test results were classified as “inconclusive”.
Phocine Distemper Virus Epizootic Investigation 2002/2003 18 Confirmation of PDV infection
Where samples were available, positive reactions in either molecular technique (RT-PCR and/or IPX) were used to confirm the presence of PDV infection. Differentiation of PDV infection resulting in clinical disease from PDV infection associated with asymptomatic viral carriage requires consideration of the results of gross pathology, histopathology and immunohistochemistry testing in combination. This appraisal was made, wherever possible, for all seals confirmed as positive for PDV infection during the investigation.
Serological Investigations (Feline Herpesvirus and Toxoplasma)
During the 1988 PDV epizootic, European common seals were found to be infected with phocine herpesvirus-1 (PHV-1). Along with the protozoan parasite (Toxoplasma sp.), these pathogens can cause systemic disease in severely immuno-compromised animals, such as phocid seals with phocine distemper. However, prior to the 2002 PDV epizootic, large- scale serological surveys of UK seals for evidence of exposure to herpesviruses and Toxoplasma sp. have never been conducted.
Seventy-four whole blood samples were collected from seals admitted to rehabilitation centres or from carcasses found on the shore during the 2002 PDV epizootic. The samples had not been centrifuged before freezing at – 20°C and were centrifuged on arrival to remove cell debris. Samples were aliquoted into 3 x 80 µl eppendorfs and stored at +4°C until use. Throughout, fresh pipette tips were used for each different serum sample in every procedure. The analyses were conducted at the Department of Veterinary Pathology, University of Liverpool.
Indirect Immunofluorescent Assay (IFA) for antibodies to feline herpesvirus (FHV)
Feline herpesvirus (FHV) antibody assays used 96 well plates with Feline Embryo cell line A (FEA) cells infected with FHV and fixed using ethanol when plaques were visible in each well. These were then stored at +4°C until required. When required the plates were rinsed three times in a phosphate buffered saline (PBS) solution. 30µl of PBS was added to all rows of wells, a further 30µl added to the odd numbered rows. 3µl of serum sample was added to the odd number rows. 30µl was removed from the odd number rows after careful mixing and transferred to the even number rows, then mixed and 30µl discarded from the even number rows. This method enabled each sample to be tested at 1/20 and 1/40 dilution.
A number of negative controls were performed on each plate, including wells with no virus and wells with no sample. Due to the unavailability of a known seal positive control, serum from a cat known to be FHV positive was used. Two samples that where seen to be positive on the initial plate were repeated on every successive plate to show consistency between plates.
After the serum samples had been added, the plate was incubated in a rocking incubator at 56°C. Routine protocols suggested incubation at 36°C but this produced high background levels of fluorescence. At 56°C, this background was much reduced and the positive and negative controls remained consistently positive and negative respectively.
Phocine Distemper Virus Epizootic Investigation 2002/2003 19 After incubation the plates were washed three times in PBS, including vigorous shaking. Dr Stuart Carter, Department of Veterinary Pathology, University of Liverpool provided anti-grey seal antibody, raised in a rabbit and stored at –20°C until use. The anti-grey seal antibody was added to each well (30µl at a dilution of 1/2000), with the exception of the cat positive control, to which PBS was added. The plate was then incubated at 36°C for one hour.
After incubation the plate was washed three times in PBS. 30µl of 1/40 Fluorescein isothiocyanate (FITC) conjugated anti-rabbit antibody was then added to every well, except the cat positive control. To this well was added 30µl of 1/40 FITC conjugated anti- cat antibody. The plate was then incubated for a further hour at 36°C, after which it was rinsed three times in PBS. Glycerol was added to each well (30µl) and the plate viewed under a fluorescent microscope.
Samples were considered positive if there was a definite and characteristic nuclear fluorescence of plaques at either dilution. Any samples that showed no positive fluorescence were repeated on three occasions, for six wells, to ensure that they were truly negative. This was to ensure that they were not negative purely because there was no virus in the well.
Toxoplasma Direct Agglutination Test
Each serum sample was diluted with PBS buffer to give two dilutions, 1/20 and 1/2000. The positive and negative controls were diluted in the same way and were from cows of known antibody status, supplied by Dr Jon McGarry, Veterinary Parasitology group, Liverpool School of Tropical Medicine. Using a 96 well round bottomed plate, 25µl of each dilution of each sample, plus the controls, including a PBS control, were transferred to separate wells. 25 µl of 2-Mercaptoethanol was added to each well. The Toxoplasma gondii antigen (from Toxo-screen DA kit, manufactured by Biomerieux, France) was diluted 1/5 with the coloured diluent provided. 50 µl of diluted antigen was added to each well before the plate was sealed with a plate cover and tapped gently to mix. The samples were then incubated overnight at room temperature.
A positive result was seen as agglutination in a mat, covering half the well base. If it covered less than this it was taken to be borderline and repeated. A negative result showed sedimentation into a button or ring. All positive results were then confirmed by a quantitative test by titrating from the 1/20 dilution. 50µl of 2-Mercaptoethanol was added to four successive wells of the plate, repeated for the number of samples plus controls. 25 µl of the sample at 1/20 dilution was added to the first well and mixed by pipetting. 25 µl was then transferred from the first well to the second and mixed. This was repeated from the second to the third and the third to the fourth, with 25µl being discarded from the fourth well. The dilution series obtained is thus: 1/60, 1/180, 1/540, 1/1620. The plate was then incubated overnight and read as above. Titres are expressed as an inverse dilution.
Carcass Disposal
Phocine Distemper Virus Epizootic Investigation 2002/2003 20 Project co-ordinators established contact with the department of the Local Authority responsible for disposal of carcasses on the beach in areas where seal colonies occur. Defra compiled guidance notes entitled “Phocine Distemper Virus in seals: Suggested disposal options for seal carcasses” (See Appendix 2.3) and “Seals and Phocine Distemper Virus (PDV): Do you own land along the coast? Letter providing guidance to private landowners along the coast” (See Appendix 2.4) and co-ordinated their distribution. Throughout the investigation, local authorities and private landowners were directed to these documents for advice on their responsibilities and recommended methods for carcass disposal.
In England, arrangements were made for the Institute of Zoology to relay to the Local Authority information received from callers regarding seal carcasses in need of disposal in their area. During the peak of the epizootic where large numbers of reports were received, faxing print outs of Microsoft Excel™ worksheets for each county proved the most efficient means of communication. Telephone and e-mail were also used to transfer information on dead seal reports to local councils. Similarly, in Scotland, Wales and Northern Ireland contacts were made with the Local Authority departments and information on carcasses in need of disposal were relayed as required.
Information Distribution
Provision of up-to-date information available in the public domain was a major priority during the investigation. Status reports detailing the geographical distribution and number of dead seal reports, post mortem examinations and diagnostic test results were issued on a regular basis. The status reports were posted in a dedicated section on the SMRU website (http://smub.st-and.ac.uk). In addition, reports were circulated electronically through e- mail lists to governmental contacts, volunteer networks and local authority officials. UK status reports were incorporated into European updates under the co-ordination of the Common Wadden Sea Secretariat. These documents were also distributed by electronic e- mail list and made available for public access on the web (http://cwss.www.de/).
The National Seal Hotline also included a short and up-to-date message regarding the PDV epizootic that could be easily accessed using the automated touch-tone system. These messages were used by callers reporting live sick or dead seals on the hotline and by parties without Internet access. Callers with specific enquiries were contacted and given advice as appropriate. The most frequently expressed concerns related to the risks of PDV transmission virus between seals and dogs following direct or indirect contact.
During the peak of the PDV epizootic in the UK, weekly video conferences were chaired by Defra with colleagues in attendance from the Countryside Division of the National Assembly for Wales, Institute of Zoology, Scottish Executive Environment and Rural Affairs Department and SMRU. These provided a forum for exchange of information on the epizootic and dynamic discussion regarding strategies for management of the investigation.
Staff at the Institute of Zoology liaised closely with the press and media, supplying regional updates to ensure accurate information was made available. Interviews for television and radio pieces and newspaper articles were performed on request through liaison with The Zoological Society of London Public Relations department. A record was kept of all media activity relating to the PDV investigation conducted by the Institute of
Phocine Distemper Virus Epizootic Investigation 2002/2003 21 Zoology (see Appendix 5.2-5.3). Media enquires in Scotland were fielded by staff at SAC Inverness and SMRU.
Aerial Census Surveys and Population Estimates
Under the Conservation of Seals Act, 1970, the Natural Environment Research Council (NERC) has the responsibility to report to the Special Committee on Seals (SCOS) information about the status of the UK seal population. This statutory obligation is devolved to the Sea Mammal Research Unit, which now has a time series of population estimates for both species of UK seal. Due to the differences in the timing of the breeding season and other life history and behavioural traits the abundance and distribution of the two species are monitored using different methods.
Grey seals
The focus of the advice to SCOS has largely been focussed on the grey seal population, whose numbers have been increasing exponentially. Grey seal females give birth to a single white-coated pup each autumn/winter (September to January depending on the region). Most of the colonies around the UK (largely in Scotland) can be photographed using fixed wing aerial surveys. The number of pups is then counted from large format photographs and 4-6 surveys of each of the major breeding sites are taken each year. From these counts a population model is fitted and an accurate estimate of the population abundance is obtained (see SMRU Reports to SCOS at http://smub.st.and.ac.uk/CurrentResearch.htm/scos.htm for more details on this method and the population trends over the past 30 years). However, grey seals are ‘central place foragers’, in which the central place or haul-out from where they travel to the feeding area can vary. This means population estimates associated with areas outside the breeding season are very difficult to determine. For example, animals using the Farne Islands on one occasion may then move to the Tay, Orkney or Shetland within a matter of a few days to forage from these new haul-out sites. It is therefore not possible to estimate ‘populations’ associated with different haul-out sites in order to estimate site-specific mortality rates.
Common seals
Following the 1988 outbreak the population monitoring series was expanded to include the common seals in the UK. Sporadic surveys had been carried out in the years prior to this but since 1989 the abundance of this species has been monitored annually using two methods. Fixed wing aerial surveys using large-format film (the same technique as was developed for the grey seals) is used for counting seals on sandbanks (such as the populations found in The Wash, Tay and Moray Firth). On rocky shore haul-out sites however, animals are too well camouflaged for this system therefore counts are made using a thermal image camera mounted in a helicopter. The seals can then be distinguished on a black and white monitor in which the hot seals are clearly visible as white shapes against the cold black rocks.
Surveys are usually carried out during August when the maximum number of seals are hauled out (Thompson and Rothery, 1987) and this allows a minimum population size to be estimated. However, research carried out by the University of Aberdeen, Lighthouse
Phocine Distemper Virus Epizootic Investigation 2002/2003 22 Field Station, indicates that counts in the Moray Firth are higher during the breeding season in July than the moult (Thompson, P.M. personal communication). These counts are therefore used to estimate population size in this area. From studies on the haul-out behaviour of common seals a ‘true’ population size can be estimated, since approximately 65% of animals will be hauled out at any one time.
(A) (B)
Fig. 1. Photograph of common seal rocky haul- out site (A). Thermal image of same haul- out site (B). Seals are now clearly visible and not camouflaged by the terrain.
Quantification of Regional Seal Mortality
The investigation employed two techniques for estimation of regional seal mortality. Estimates based on seal carcass reports were calculated as the first method (pending data derived from aerial surveys). Figures on total seal carcass counts and the proportion of grey and common seals within the subset of carcasses identified to species level were extrapolated to predict overall species mortality levels. The second (more robust) technique uses comparison of pre and post-epizootic population estimates obtained from the aerial census surveys as described above.
Phocine Distemper Virus Epizootic Investigation 2002/2003 23 • Results
Monitoring of UK seal mortality (via the National Seal Hotline)
In total 4361 reports of dead seals were received between the 14th August 2002 and 18th August 2003 for the UK. The total numbers of dead seal reports recorded (including species proportions) in each country are shown in Table 1 and Figure 2. The vast majority of these seal reports were obtained from The Wash, England between mid-August and the end-October 2002 (see Figures 3-5). It should be noted that these data refer to seals reports received, and should not be considered synonymous with the actual number of seals that died. Several reports may be received for any individual seal, and some degree of duplication of individual seals reports is therefore inevitable within the dataset. It is also likely that many dead seals were either not found or were found but were not reported.
Table 1: Number of Dead Seal Reports by Region and Species
England Scotland Wales Northern Ireland UK Phoca vitulina 491 103 0 57 651 Halichoerus grypus 113 480 181 26 800 Unidentified 2464 412 3 31 2910 Total 3068 995 184 114 4361
Fig. 2: Regional distribution of dead seal reports (Aug 2002-Aug 2003)
3500 3000 2500 2000 1500
Frequency 1000 500 0 England Scotland Wales Northern Ireland
Phoca vitulina Halichoerus grypus Unidentified
Figures 3 and 4 illustrate the rapid increase in dead seal reports for England to a peak value in mid-September 2002 and the subsequent gradual decline to a low level from December 2002. Figures 5-8 show the temporal distribution of dead seal reports received within England, Scotland, Wales and Northern Ireland.
Phocine Distemper Virus Epizootic Investigation 2002/2003 24 Fig. 3: Weekly total of dead seal reports in the UK
500 ENGLAND 400 SCOTLAND 300
200 WALES
seal reports 100 NORTHERN Weekly total of dead 0 IRELAND 1 5 9 1317212529333741454953 Week of epidemic (start 14.08.02)
Fig. 4: Cumulative total of dead seal reports in the UK 3500 ENGLA ND 3000 2500 SCOTLAND 2000 1500 1000 WALES 500 dead seal reports seal dead Cumulative total of 0 NORTHERN 1 5 9 1317212529333741454953 IRELA ND Week of epidemic (start 14.08.02)
Fig. 5: Temporal distribution of dead seal reports in England (Aug 2002 - Jul 2003)
3000 2500 2000 1500 1000 Frequency 500 0 Aug-Oct Nov-Jan Feb-Apr May-Jul
Phocine Distemper Virus Epizootic Investigation 2002/2003 25 Fig. 6: Temporal distribution of dead seal reports in Scotland (Aug 2002 - Jul 2003)
700 600 500 400 300
Frequency 200 100 0 Aug-Oct Nov-Jan Feb-Apr May-Jul
Fig. 7: Temporal distribution of dead seal reports in Wales (Aug 2002 - Jul 2003)
120 100 80 60 40 Frequency 20 0 Aug-Oct Nov-Jan Feb-Apr May-Jul
Fig. 8: Temporal distribution of dead seal reports in Northern Ireland (Aug 2002 - Jul 2003)
60 50 40 30 20 Frequency 10 0 Aug-Oct Nov-Jan Feb-Apr May-Jul
Phocine Distemper Virus Epizootic Investigation 2002/2003 26 Pathological Investigations
A total of 257 seal carcasses were examined or sampled in the UK between August 2002 and August 2003 consisting of 164 common seals and 93 grey seals (Table 2). Post mortem examinations of dead seals were conducted using standardised protocols (see Appendix 4).
Table 2: Total number of post mortem examinations performed during the investigation (Aug 2002-Aug 2003)
Country England Scotland Wales Northern Ireland UK Phoca vitulina 109 37 0 18 164 Halichoerus grypus 13 57 19 4 93 Total 122 94 19 22 257
In England, 42% (51/122) of necropsies were performed at the Institute of Zoology (IoZ), 29% (35/122) at the Norfolk RSPCA Wildlife Hospital, 19% (24/122) by veterinary schools and 10% (12/122) by others. All necropsies in Scotland were performed at SAC Inverness, in Northern Ireland at the Veterinary Sciences Division, Department of Agriculture and Rural Development, and in Wales by Liverpool University Veterinary Pathology Department (15/19) and the IOZ (4/19).
Age categories used for these analyses are defined in the Methods section. Using these age categories, common seal pups (considered in their first year of life) weighed 6.6-24.0kg, juveniles (probably > 1 year old) 19.1-40.0kg, and adults 37.0-92.0kg. For grey seals, pups weighed 10.5-42.0kg, juveniles 36.5-120.0kg, and adults 66.5-163.0kg. Of the 164 common seals examined or sampled in total, 82 were pups, 41 were juveniles/subadults, 34 were adults and 7 had undetermined age category. Of the 93 grey seals examined, 62 were pups, 12 were juveniles/subadults, 18 were adults and 1 had undetermined age category.
PDV infection and phocine distemper
From the outset, it is important to make the distinction between infection with PDV, and phocine distemper. A seal can be infected with PDV but still be in either good health or die of disease or trauma unrelated to PDV infection. Phocine distemper is the potentially fatal disease that can result from PDV infection. A range of factors probably help to determine whether PDV infection results in a severe or fatal case of phocine distemper. Susceptibility to PDV-induced disease can be highly species-specific, as is seen with the highly resistant grey seals compared to the more susceptible common seals (at least in some parts of Europe). Other possible factors influencing susceptibility to PDV include whether the seal has had any previous exposure (i.e. acquired immunity) to PDV, how immunocompetent the seal is when exposed to the virus, and whether other stressors (such as poor nutritional status or concurrent parasitic infestation) can help to compromise the resistance of the seal to the virus. If a seal becomes infected with PDV then mounts an immune response and survives, it is likely that the seal will have lifelong immunity to future infection. It is
Phocine Distemper Virus Epizootic Investigation 2002/2003 27 therefore important not to assume that all seals that are PDV positive (i.e. infected with PDV) will necessarily die (or have died) as a result of infection with the virus.
The distinction between PDV infection and phocine distemper is particularly important in areas where common seal abundance and density are high but epizootic mortality was not observed (e.g. Scotland). It is possible that seals in these regions could have increased resistance to PDV, resulting in lower levels of mortality due to phocine distemper. It is also important in seal species (such as grey seals) that are known to be highly resistant to PDV as a species-specific phenomenon.
Criteria for diagnosis of death due to phocine distemper
In order to attribute the cause of death of a seal to phocine distemper, the pathologist must demonstrate gross and microscopic lesions characteristic of, or at least consistent with, phocine distemper (e.g. acute interstitial pneumonia, lymphodepletion, non-suppurative meningoencephalitis, eosinophilic inclusion bodies in epithelia or CNS tissue) (e.g. Kennedy 1998) in conjunction with the demonstration of PDV infection in tissues using a standard diagnostic test (e.g. immunoperoxidase test or RT-PCR).
In some common seals infected with PDV, gross or histological lesions consistent with phocine distemper were mild or absent. Many of these cases had severe conditions (e.g. heavy lungworm infections, cellulitis, emaciation, etc.) that could have caused the death of the seal even in the absence of PDV infection. Although the role of PDV cannot be excluded from the cause of death in these PDV-infected cases, the parasitic and/or bacterial diseases (or loss of nutritional status) were considered more significant. Consequently, the cause of death in these cases was attributed to a combination of the principal (e.g. parasitic/bacterial) lesions and/or starvation in combination with PDV infection, rather than death directly due to phocine distemper.
Gross pathology of common seals with phocine distemper
Using the criteria described above, phocine distemper was attributed as the cause of death of 72 of the 164 common seals necropsied in the UK. Another 8 common seals found in The Wash during the peak of the epizootic were suspected to have died of phocine distemper but either histopathological and/or molecular diagnostic tests were not conducted to identify distemper-like lesions or confirm the presence of PDV. Another 12 common seals were infected with PDV but had other conditions (e.g. heavy parasitic infections) considered the most probable cause of death. Although 10 grey seal carcasses were confirmed to be infected with PDV, none were considered to have died due to phocine distemper.
The 72 common seals diagnosed to have died of phocine distemper were found in a range of nutritive conditions from good to poor/emaciated. All age categories (pups, juveniles and adults) were affected consistent with epizootic-type mortality. Externally, conjunctivitis (bilateral), corneal ulceration, (mucopurulent) nasal discharge, and ulcers of the tongue, buccal mucosa or hard palate were common findings. Some carcasses appeared severely dehydrated.
Gross lesions were most frequently and consistently found in the lungs including pulmonary congestion/hyperaemia and oedema. Copious serous, sero-mucoid, sero-
Phocine Distemper Virus Epizootic Investigation 2002/2003 28 purulent or sero-sanguinous (often frothy) fluid was commonly found within the trachea and bronchi. Pulmonary interstitial (intra- and inter-lobular) emphysema was virtually ubiquitous and frequently extended into sub-pleural, mediastinal, pericardial and subcutaneous locations. Subpleural bullous emphysema was occasionally noted but unilateral (tension) pneumothorax was seen in at least 3 cases. In some seals with phocine distemper, areas of gross pulmonary consolidation were identified.
Other common gross findings included marked thymic atrophy, enlarged or normal-sized lymph nodes and these often appeared oedematous or had haemorrhagic foci on cross section. Diarrhoea or gross lesions consistent with enteritis were infrequently seen. Petechial haemorrhages in multiple organs were also common in seals with phocine distemper associated with concurrent generalised secondary bacterial infections.
Other gross lesions included a range of typical parasitic lesions normally found in common seals (especially in pups/yearlings). These included nematodes in bronchi, alveoli, pulmonary blood vessels, heart, stomach, intestine and small cestodes within the small intestine. Numerous ectoparasites (lice) were found on the skin of one seal.
Histopathology of common seals with phocine distemper
The most consistent and severe lesion associated with phocine distemper virus infection was severe, diffuse and acute (sometimes necro-haemorrhagic) (broncho-)interstitial pneumonia. Alveolar and interstitial (intra- and inter-lobular) emphysema was frequently associated with these lesions. Areas of bronchial epithelial necrosis were seen, but these were often difficult to differentiate from post-mortem epithelial sloughing. Intra-cytoplasmic bronchial inclusion bodies were rarely, if ever, identified with confidence. In a few (possibly very early-stage) cases there was multifocal acute broncho-interstitial pneumonia characterised by areas of intense hyperaemia, marked interstitial and intra-alveolar oedema and haemorrhage distributed in a distinctly bronchial pattern. In most cases, however, the interstitial pneumonia was severe and diffuse. In some cases, subacute (broncho-)interstitial pneumonia was found characterised by marked type II pneumocytosis and abundant intra-alveolar foamy macrophages. Syncytial cells and eosinophilic inclusions were possibly seen, but these were extremely rare and therefore difficult to identify with confidence.
In many cases, the only pulmonary lesions seen microscopically were acute interstitial pneumonia and (often marked) interstitial emphysema. In other cases, mild to severe secondary (necro)suppurative bronchopneumonias were identified, and these were often associated with basophilic bacterial aggregates.
Apparent lymphodepletion was consistently seen in the spleen, bronchial, mesenteric (or other) lymph nodes, and the thymus. Very rare foci of lymphocytolysis within lymph node or spleen were seen but syncytia or inclusion bodies were generally absent. Sinus hyperplasia of lymph nodes and extramedullary haematopoiesis in the spleen (and sometimes in the liver) were also common findings. Acute necro-ulcerative dermatitis associated with eosinophilic intracytoplasmic inclusion bodies and bacterial aggregates were infrequently seen. Many seals also had ulcers in the mouth suggestive of necrotising ulcerative stomatitis, but few were examined histologically. A few seals had microscopic evidence of a haemorrhagic gastritis.
Phocine Distemper Virus Epizootic Investigation 2002/2003 29 Intracytoplasmic eosinophilic/amphophilic inclusion bodies were rarely seen in the transitional epithelium of the bladder, sometimes associated with hydropic-type swelling and eccentrically located nuclei within epithelial cells. A haemorrhagic cystitis was also found in at least one case. Intracytoplasmic eosinophilic inclusion bodies were very rarely seen within the transitional epithelium of the renal pelvis or the biliary epithelium in a few seals. Occasional seals also had microscopic evidence of renal tubular necrosis, glomerular fibrin thrombi or larger foci of renal coagulative necrosis (infarcts?). The pathogenesis of these lesions was probably related to renal hypotension or shock rather than directly due to viral infection.
In general, most seals that died of phocine distemper perished before lesions in internal tissues other than the lungs and lymphoid tissue were found. However, in a small number of cases a non-suppurative meningoencephalitis was associated with eosinophilic intracytoplasmic and intranuclear inclusion bodies in neurones (especially the cerebrum) and intracytoplasmic inclusion bodies in glia (cerebrum/cerebellum). The brain was the only organ where eosinophilic intranuclear inclusion bodies were ever found. Congestion and perivascular oedema within parenchyma and meninges, gliosis, neuronophagia, neuronal degeneration/necrosis, mild mononuclear cell perivascular cuffing and mild multifocal demyelination within the cerebellar folia were other CNS lesions considered consistent with phocine distemper.
Necropurulent or haemorrhagic microfoci in multiple organs were frequent findings in seals with systemic (secondary) bacterial infections. Suppurative meningitis or meningoencephalitis was occasionally associated with generalised bacterial infections. Other lesions of probable bacterial origin seen in seals with phocine distemper included occasional cases of septic arthritis (probably as a sequel to bite marks on the flippers), septic peritonitis (some cases associated with an umbilical abscess), and cellulitis. Cultures of some of these lesions yielded Streptococcus spp. among other bacterial organisms.
Apart from rare inclusion bodies in the biliary epithelium, non-specific hepatic lesions including multifocal-diffuse (often perivenular) hepatocellular degeneration and necrosis (sometimes associated with large, spherical, weakly eosinophilic and slightly granular intracytoplasmic inclusions), and may have been anoxic changes secondary to hypotension. Multifocal massive acute coagulative hepatocellular necrosis, or non-zonal scattered foci of acute hepatic necrosis (both without inclusion bodies) were seen in some liver sections and were considered consistent with possible systemic (secondary) phocine herpesvirus-1 (PHV- 1) or toxoplasma infection (pending immunohistochemical investigations). A significant proportion of common seals tested for antibodies to both herpesvirus and toxoplasma (T. gondii) were found to be seropositive (see Serological investigations).
Alongside the pulmonary lesions considered to be of viral and (secondary bacterial) origin, multifocal, granulomatous interstitial pneumonia (of probable verminous aetiology) was also commonly seen in seals with parasitic lung infections. One seal also had a subacute-chronic eosinophilic-lymphocytic pneumonia (possibly due to aberrant microfilarid migrants). In rare cases a predominantly non-suppurative or eosinophilic meningoencephalitis was characterised by perivascular cuffs of either eosinophils or eosinophils, neutrophils and mononuclear cells. The cause of these lesions was not identified, although they were suggestive of systemic (secondary) toxoplasmosis (tachyzoites were not conclusively seen) or aberrant nematode larval migration.
Phocine Distemper Virus Epizootic Investigation 2002/2003 30 PDV immunohistochemistry (IPX) staining
A range of tissues demonstrated positive labelling of antigen on PDV immunoperoxidase (IPX) test. The tissues included: lungs, liver (bile duct epithelium), thyroid gland, spleen, bronchial/mesenteric lymph node, ovary, kidney (epithelium of renal pelvis).
Bacteriological findings
Secondary pulmonary or generalised bacterial infections were very common findings in seals with phocine distemper. The most common bacterial pathogens isolated were Streptococcus phocae, Streptococcus canis, Escherichia coli, and Bordetella bronchiseptica. Other less frequently isolated pathogens causing generalised bacterial infections included Proteus mirabilis, Vibrio vulnificus and Pasteurella haemolytica. Brucella species (including Brucella pinnipediae) were also isolated from 4 common seals from Northern Ireland, 6 common seals from Scotland and a grey seal from Cornwall, England.
Mycological findings
Secondary pulmonary or systemic mycotic infections were quite rare although at least one common seal with phocine distemper had a generalised Aspergillus fumigatus infection.
Serological investigations
Serum from 61 common seals and 4 grey seals from England (North Sea coast), and 5 grey seals from Wales were tested for antibodies to feline herpesvirus (FHV) and Toxoplasma gondii.
Common seals
Antibodies to feline herpesvirus (FHV)
Positive antibodies titres to feline herpesvirus were found in 25/61 (41%) common seals comprising 3/21 (14%) pups, 9/22 (41%) juveniles, 1/2 (sub)adults (50%), and 12/16 (75%) adults tested.
Antibodies to Toxoplasma gondii
For the 61 common seals tested, one sample was unreadable. Of the remaining 60 common seals, positive antibodies titres to Toxoplasma gondii were found in 35/60 (58.3%) common seals comprising 11/21 (52%) pups, 13/22 (59%) juveniles, 2/2 (sub)adults (100%), and 9/15 (60%) adults tested.
Grey seals
Antibodies to FHV
Positive antibodies titres to feline herpesvirus were found in 5/9 (55.5%) grey seals comprising 3/6 (50%) pups, 2/2 (100%) juveniles and 0/1 (sub)adults (0%) tested.
Phocine Distemper Virus Epizootic Investigation 2002/2003 31 Antibodies to T. gondii
Positive antibodies titres to T. gondii were found in 3/9 (33%) grey seals comprising 3/6 (50%) pups, 0/2 (0%) juveniles and 0/1 (0%) (sub)adults tested.
Patterns of PDV exposure in UK seals
During the course of the investigation 142 common seal and 72 grey seal carcasses were tested for presence of PDV within tissue samples using molecular diagnostic techniques (RT-PCR and/or PDV immunoperoxidase test). These diagnostic tests were essential for confirming the presence of PDV in dead seals. Of the seals tested by one or both methods, 97 common and 10 grey seals were PDV-positive comprising 83 common and 1 grey seal from England, 12 common and 9 grey seals from Scotland, and 2 common seals from Northern Ireland. No seals were found to be PDV-positive in Wales.
There were 45 common seals and 62 grey seals found to be negative for PDV using molecular diagnostic tests. These consisted of 14 common and 9 grey seals from England, 15 common and 33 grey seals from Scotland and 16 common and 4 grey seals from Northern Ireland. All 16 grey seals tested from Wales were found to be negative. Within England, all 3 grey seals from Cornwall and one common seal from the small population near Chichester Harbour were negative. In Scotland, all 4 seals (2 common; 2 grey) tested from Shetland were also negative.
Due to the state of decomposition or other factors, 22 common seals and 21 grey seals were examined but were not tested for the presence of PDV by molecular diagnostic methods.
The abundance and spatial distribution of common and grey seals positive and negative for PDV (plus those examined but not tested) from July 2002-January 2003 in the UK are shown in Figures 9-10.
Details of the first, or index, case and last confirmed case by species for each region are shown in Table 3.
Table 3: Dates found of index and last confirmed cases of PDV infection by region and species
Country Date of index case Date found of last confirmed case Phoca vitulina Halichoerus grypus Phoca vitulina Halichoerus grypus England 18 July 2002 4 September 2002 29 October 2002 4 September 2002 Scotland 11 September 2002 13 September 2002 23 January 2003 6 January 2003 N. Ireland 8 October 2002 --- 12 October 2002 --- Wales ------UK 18 July 2002 4 September 2002 23 January 2003 6 January 2003
Phocine Distemper Virus Epizootic Investigation 2002/2003 32 Figure 9: Spatial distribution of PDV-positive, PDV-negative and non-tested common seals necropsied in UK (Jul 2002-Jan 2003)
Figure 10: Spatial distribution of PDV-positive, PDV-negative and non-tested grey seals necropsied in UK (Jul 2002-Jan 2003)
Phocine Distemper Virus Epizootic Investigation 2002/2003 33 The proportions of PDV-positive and PDV-negatives within common seals from The Wash (Figure 11), common seals from Northern Ireland (Figure 12), and common (Figure 13) and grey seals from Scotland (Figure 14) are also illustrated. The temporal and spatial spread of positive PDV case confirmations throughout 2002 in the UK are illustrated in Figure 15.
Common seals - The Wash (Jul-Oct 2002) Common seals - N Ireland Oct-Dec 2002
PDV POSITIVE PDV POSITIVE PDV NEGATIVE PDV NEGATIVE
Figure 11: Proportion of PDV-positive and Figure 12: Proportion of PDV-positive and PDV-negative common seals from The Wash PDV-negative common seals from Northern (based on molecular diagnostic tests) (Jul-Oct Ireland (based on molecular diagnostic tests) 2002) (Oct-Dec 2002)
Common seals - Scotland Aug 02-Jan 03 Grey seals - Scotland Aug 02-Jan 03
PDV POSITIVE PDV POSITIVE PDV NEGATIVE PDV NEGATIVE
Figure 13: Proportion of PDV-positive and Figure 14: Proportion of PDV-positive and PDV-negative common seals from Scotland PDV-negative grey seals from Scotland (based on molecular diagnostic tests) (Aug (based on molecular diagnostic tests) (Aug 2002-Jan 2003) 2002-Jan 2003)
Age and sex structure of PDV-positive seals
Common seals
Of the 94 PDV-positive common seals examined after death in the UK during this investigation, 37 were pups, 31 juveniles and 26 adults. Of these, 45 were male and 48 were female.
This age distribution was mirrored for common seals from England where roughly equal proportions of PDV-positive pups (n=29), juveniles (n=31) and adults (n=22) were identified. This age distribution was also mirrored for common seals from The Wash (Norfolk and Lincolnshire) where roughly equal proportions of pups (n=26), juveniles (n=23) and adults (n=18) were infected.
Phocine Distemper Virus Epizootic Investigation 2002/2003 34 July 2002 August 2002 September 2002
October 2002 November 2002 December 2002
January 2003
Fig. 15: The geographical and temporal spread of PDV in UK common and grey seals July 2002-January 2003
In Scotland, 7 pups, 1 juvenile and 4 adult common seals were found to be PDV-positive. In Northern Ireland, one common seal pup and one (sub)adult were PDV positive.
Phocine Distemper Virus Epizootic Investigation 2002/2003 35 Grey seals
Of the 10 grey seal carcasses (4 male, 6 female) found in the UK (9 from Scotland) that tested positive for PDV, 6 were pups, 3 were juveniles, and 1 was an adult.
Patterns of UK seal mortality
A total of 257 carcasses (comprising 164 common and 93 grey seals) were examined or sampled in the UK between August 2002 and August 2003 (Table 2). The spatial distribution of the location that these carcasses were found is shown in Figure 16.
Detailed post mortem findings following standardised protocols (see Appendix 4) were available for 142 common seals and 87 grey seals examined between August 2002 and August 2003 inclusive. The frequencies of these causes of death for common and grey seals are shown in Table 4.
Table 4: Frequencies of causes of death of 142 common seals and 87 grey seals examined in detail at post mortem between August 2002 and August 2003
Cause of death Common seal Grey seal Total
Phocine distemper (incl. 8 suspected) 80 0 80 Starvation 15 13 28 Physical trauma 8 21 29 Pneumonia (parasitic/bacterial) 14 7 21 Cellulitis/peritonitis 3 5 8 Heavy parasitic infections 4 3 7 Euthanased 0 7 7 Generalised bacterial infection 2 3 5 By-catch 1 1 2 Meningoencephalitis 2 0 2 Others 4 5 14 Not established 9 22 31
Total 142 87 229
Phocine Distemper Virus Epizootic Investigation 2002/2003 36 Common seals
Phocine distemper
Phocine distemper was the most common cause of death of UK common seals during the 2002 PDV epizootic. Based on the previously defined criteria, 72 common seal carcasses found in the UK were diagnosed to have died due to phocine distemper. Another 8 common seals found in The Wash during the peak of the epizootic were suspected to have died of phocine distemper, but histopathological and/or molecular diagnostic tests were not conducted to identify distemper-like lesions or to confirm the presence of PDV.
The first fatal case of phocine distemper in the UK was diagnosed in a common seal from The Wash that was found on 18/07/02. The last fatal case of phocine distemper in The Wash was diagnosed in a common seal found on 29/10/02. The first fatal case of distemper in Scotland was in a common seal in Highland on 11/09/02. The last fatal case of phocine distemper in the UK was in a common seal in East Highland, Scotland on 21/01/03. Although two common seals were infected with PDV in Northern Ireland in October 2002, it is not known if the infection caused the death of the seals.
Most fatal phocine distemper cases occurred in The Wash common seal population, and very few cases of phocine distemper were diagnosed in other regions (see Figure 16). A comparison of the frequencies of phocine distemper and non-phocine distemper mortality in common seals found in The Wash and in Scotland between July 2002 and January 2003 are shown in Figures 17 and 18.
Figure 16: Distribution of common seals that died of phocine distemper
Phocine Distemper Virus Epizootic Investigation 2002/2003 37 Temporal distribution of necropsied common seal Temporal distribution of necropsied common seal deaths due to phocine distemper and other deaths due to phocine distemper and other causes from The Wash Aug 2002-Jul 2003 causes in Scotland Aug 02-Jul 03
60 20 50 15 40 30 10 20 5 Frequency Frequency 10 0 0 Aug-Oct Nov-Jan Feb-Apr May-Jul Aug-Oct Nov-Jan Feb-Apr May-Jul phocine distemper other causes phocine distemper other causes Figure 17 Figure 18
The age and sex structure of all common seals in the UK diagnosed to have died due to phocine distemper is shown in Figure 19. As is the case with PDV exposure, fatal cases of phocine distemper were relatively evenly distributed across all ages, although the proportion of male and females varied between age categories.
Age and sex structure of all necropsied UK common seals that died of phocine distemper (Jul 2002-Jan 2003) 25
20
15 Male 10 Female Frequency 5
0 pup juvenile adult
Figure 19
The proportion of all PDV-positive common seals necropsied from The Wash that died of phocine distemper was very high (63/69 = 91%). Only 9% of PDV-positive necropsied common seals from The Wash died of other causes (Figure 20) during the investigation. In contrast, a lower proportion of confirmed PDV-positive common seals from Scotland were considered to have died of phocine distemper (6/12 = 50%) (Figure 21).
Proportion of PDV-positive common seals from Proportion of Scottish PDV-positive common The Wash that died of phocine distemper and seals that died of phocine distemper and other other causes causes
other causes other causes
phocine phocine distemper distemper
Figure 20 Figure 21
Phocine Distemper Virus Epizootic Investigation 2002/2003 38 Other causes of mortality
A range of other causes of death were identified in common seals during the investigation (see Table 4). Within these other cause of death categories, 3 common seals that died of heavy parasitic infections, 2 that died of cellulitis/peritonitis, and single cases of fatal parasitic/bacterial pneumonia, (eosinophilic) meningoencephalitis and combined meningitis/generalised bacterial infection were also infected with PDV. The role (if any) of PDV infection in the death of these latter cases is not known. Of the 8 fatal cases of acute physical trauma, 2 (Scottish seals) were shot, one was considered storm damage and one was probably hit by a boat’s propeller.
Grey seal mortality
Although 10 grey seal carcasses were confirmed to be infected with PDV, none were considered to have died due to phocine distemper. A range of causes of death were identified in grey seals (see Table 4). Of the 21 cases of acute physical trauma, 11 were attributed to storm damage, 2 to being shot, 1 to a severe blow to the head, and one to a ligature from a net. No significant gross pathology was detected on post mortem examination of seven pups that were euthanased.
Phocine Distemper Virus Epizootic Investigation 2002/2003 39 Quantification of UK Seal Mortality
Post-Epizootic Air Survey Counts
Common seals
Two populations of common seals occur on the east coast of the Scottish mainland (Tay and Moray Firth) however, the largest populations are found in Shetland and Orkney. In England most of the common seals occur in the southeast of England (see Figure 22)
Figure 22: Locations of major common seal populations (moulting/haulout sites) on the east coast of the UK.
The results of the common seal air surveys carried out in early August 2002 and 2003 are given in Table 5. For some areas counts were repeated on consecutive days to estimate variability. Bad weather prevented a planned survey of Orkney in 2003.
Phocine Distemper Virus Epizootic Investigation 2002/2003 40 Table 5. Numbers of common seals counted ashore at major east coast haul-out sites during their August moult in 2002 and 2003 (pre and post the PDV epizootic)
Location Area Counts 2002 (pre- Counts 2003 epizootic) (post- epizootic) First Second First Second count count count count Dornoch, Beauly, Cromarty 438 759 Moray Firths and Ardersier (Inner Firth Moray Firth) Findhorn 144 167 Dornoch to Loch Fleet 62 56 52
644 982 Total
Abertay, Tentsmuir, Tay Broughty Ferry and estuary Buddoness and the Upper 327 368 Tay Eden Estuary 341 93
668 461 Total
Wash 2916 3037 2529 2496 Wash Blakeney point 631 346 400 Donna Nook 231 341
3778 3270 Total
SE Thames, Essex, Kent, 75 101 England Suffolk
Moray Firth
The number of animals counted in the Inner Moray Firth in 2002 was significantly lower than counts in previous years (1141 in 1997 and 838 in 2000). In contrast there had been a slight increase in the numbers of seals at haulout sites adjacent to the Inner Moray Firth (particularly at Findhorn and on the coast from Dornoch to Dunbeath). However, the count in 2003 recorded a substantial increase in numbers moulting in the Phocine Distemper Virus Epizootic Investigation 2002/2003 41 Inner Moray Firth (approximately 1.5 times the 2002 count), with numbers of animals outside this region remaining very similar. These results may suggest some changes in the movements of animals between sites in different years, although we have no movement data from tracking studies that can substantiate this.
There is clearly no significant drop in the numbers of common seals in this area that could be attributed to PDV related mortality. This corresponds with the very small number of common seal carcasses found in this area during the course of the outbreak.
Tay Estuary
The number of animals in the Tay estuary itself was about the same in 2002 and 2003. However, the number found in the Eden estuary was substantially lower in 2003, after the epizootic (approximately one third of the 2002 count). This has reduced the total counted in the region by about 30%. The Eden estuary is a haulout very prone to human disturbance so it is difficult to interpret a single count. It is very possible that the low number recorded was indeed due to disturbance and not because the population size has been reduced by PDV. Again, very few dead seals were reported in this region or along the surrounding coastline (approximately 46). Further boat counts in this area will enable us to determine if this is a true reduction.
The Wash
The number of animals counted in The Wash in 2003, post- epizootic was surprisingly high. Compared to the 2002 pre- epizootic count the numbers were reduced by only 13 - 18%. This indicates that the impact of the epizootic on The Wash population was very much less than expected, particularly following the high number of dead seal reports through the National Seal Hotline along the coast of Norfolk and SE England. By comparison an approximately 50% reduction in numbers was recorded following the 1988 outbreak.
Interestingly the number of seals recorded in the Thames estuary was also similar to that found in 2002. A discreet group of seals is also now found on Goodwin Sands where 79 were counted in 2003.
Grey seals
As explained above, it is not possible to estimate site-specific mortality rates in grey seals. However, the number of dead grey seals found overall during 2002 was very low compared to the estimated UK population size (<500 carcasses were identified as grey seals between July and end October. This compares with a current population estimate of around 120,000). A similar finding was reported after the 1988 outbreak, although there was some reduction in pup production during that year, which may have been attributable to the outbreak.
Phocine Distemper Virus Epizootic Investigation 2002/2003 42 Comparative epidemiology of the 1988 and 2002 UK PDV epizootics
In 1988, first exposure to PDV occurred in The Wash common seal population. Figure 23 shows the population trajectory for common seals in The Wash based on minimum population counts from aerial surveys. The impact of the 1988 epizootic can clearly be seen. The number of animals counted was reduced by 51% between 1988 and 1989. The population appeared to have just returned to its 1988 level when the second epizootic occurred (Thompson, D. and Duck, C. et al., Unpublished data).
4000
3000
1988 epidemic
2000
1000
0 1965 1970 1975 1980 1985 1990 1995 2000 2005 year Figure 23: Population trajectory for common seals in The Wash (based on minimum population counts from aerial surveys)
The second UK PDV epizootic in 2002 was also precipitated by initial PDV infection within The Wash common seal population. However the proportional impacts of the 1988 and 2002 PDV epizootics differed (Figure 24). In 1988 approximately 40-50% of the total Wash common seal population died, whereas the proportional mortality for this population was only 13-18% during the 2002 epizootic. Although the common seal mortality was much lower in all Scottish common seal colonies than in The Wash population in both 1988 and 2002, there was still a detectable decline in 1998 in common seal population size of 13% and 16% in the Tay and Moray Firth respectively (Figure 24). In contrast, there appeared to be no perceptible increase in common or grey seal mortality in any parts of the UK other than in The Wash in 2002 (although aerial census data for Orkney are still pending).
A comparison of the temporal distribution of dead seal reports for The Wash, Moray Firth and the Tay (using Julian dates) in the 1988 and 2002 PDV epizootics are shown in Figures 25-27. These data show that there is a lag of a few weeks in the timing of the epizootic comparison of 1988 & 2002 dead seal reports.
Phocine Distemper Virus Epizootic Investigation 2002/2003 43 1988 2002
Figure 24: Proportional common seal mortality due to 1988 and 2002 PDV epizootics (using available SMRU aerial survey data)
100
80
%
e 60
v
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t
a
l
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m 40
u
C
20
WASH2002 0 WASH88 100 200 300 400 Julian Date
Figure 25: Comparative epizootic curves (for 1988 and 2002) based on dead seal report data for England (The Wash)
Phocine Distemper Virus Epizootic Investigation 2002/2003 44 100
80
%
e 60
v
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a
l
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m 40
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MF2002 0 MFIRTH88 100 200 300 400 Julian Date
Figure 26: Comparative epizootic curves (for 1988 and 2002) based on dead seal report data for the Moray Firth – Scotland
100
80
%
e 60
v
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TAY2002 0 TAY88 100 200 300 400 Julian Date
Figure 27: Comparative epizootic curves (for 1988 and 2002) based on dead seal report data for the Tay Estuary (Scotland)
Phocine Distemper Virus Epizootic Investigation 2002/2003 45 Opportunistic Reporting of Dead Seals (National Seal Hotline)
Telephone Reporting
Greenland Interactive registered a total number of 4355 calls to the National Seal Hotline during the period 13th August 2002 to 28th July 2003. The greatest weekly call number of 510 was experienced in the middle of September 2002 (see Figure 28), corresponding to the peak of the epizootic in The Wash population. See Appendix 5.4 for a detailed breakdown of call frequency and duration during the investigation.
Representatives from Local Authorities, HM Coastguard, regional police and RSPCA call centres frequently forwarded details of dead seal reports they received directly from members of the public to the hotline.
Fig. 28: Number of calls registered by the National Seal Hotline on a weekly basis for the UK
600
500
400
300
200
registered calls 100 Weekly number of 0 1 3 5 7 9 111315171921232527293133353739414345474951 Week of investigation (start 14.08.02)
Electronic Reporting
The number of opportunistic dead seal reports from the public made by e-mail was small in comparison with those received by telephone. Nevertheless, electronic communication was the preferred means of contact of some reporters. In addition, the quality of information supplied by e-mail was often greater than that left as a message by callers on the telephone.
Systematic Reporting of Dead Seals
A detailed analysis of each stage of the volunteer appeal and survey response is included (see Appendix 7). This is intended to provide a guide for the future should volunteer schemes for the investigation of wildlife disease outbreaks be considered in
Phocine Distemper Virus Epizootic Investigation 2002/2003 46 the UK. A summary of the information pertinent to the appraisal of the scheme and consequently its application in the future are included in this section.
Volunteer Recruitment
For England, a total number of 152 individuals contacted the Institute of Zoology as “potential” volunteers (i.e. individuals who made contact expressing interest in participating in the volunteer scheme following the appeal). The peak response occurred during late September, approximately 4-5 weeks after the investigation was launched, with a modal date of 26th September 2002. For Wales, a total number of 14 individuals contacted Marine Environmental Monitoring as “potential” volunteers. The peak response occurred during early October 2002. No data is available for the initial date of contact of the Scottish volunteer network.
In retrospect, the peak of the PDV epizootic occurred in mid September 2002 and so the bulk of the volunteer team were not recruited until after this point. Individuals who responded to the appeal in the early stages were often those involved with animal rescue organisations (e.g. BDMLR) or land wardens. However the total number of respondents to phases one and two of the appeal were insufficient to provide the anticipated range of coastal coverage therefore the decision was made to appeal to the general public for assistance. The peak response to the targeted press release from the public occurred after a short lag period and this method proved effective for rapidly contacting larger numbers of individuals. The national co-ordinators noted variable regional attitudes and concern regarding the PDV epizootic that also affected the success of volunteer recruitment. The small number of volunteers recruited in Wales is probably due to the fact that PDV was not confirmed in the area and had not affected the grey seal population in 1988. There are no large common seal colonies in Wales.
The 152 “potential” volunteer contacts for England came from a wide range of geographical regions. Approximately 28% of “potential” volunteers came from The Wash region (i.e. Norfolk and Lincolnshire) and 15% from Cornwall. In Scotland, a stronger response to the volunteer appeal was experienced on the east than west coast despite the populations of seals being greater in the latter. In Wales, volunteers came from a fairly wide area of coast although half were from Gwynedd.
Of the 152 “potential” volunteer contacts for England, approximately half reported at least one survey result. Stated reasons for deciding not to participate in the scheme included time commitments, ill health, travel abroad, moving job or home and risk of transmission to dogs. Similarly, in Wales half of the 14 “potential” volunteer contacts continued to report at least one survey result.
Volunteer Surveys
In all regions, the majority of first survey reports were not received until October 2002. Considerable variation was noted in the duration (i.e. interval between the first and last survey), and the total number, of surveys that volunteers contributed during the scheme. However, the number of individuals who participated throughout the entire duration of the study period was relatively small.
Phocine Distemper Virus Epizootic Investigation 2002/2003 47 Approximately half of active volunteers saw at least one dead seal during their surveys with values of 47% (N=29), 45% (N=29) and 43% (N=3) for England, Scotland and Wales respectively. The total number of dead seals observed by the entire volunteer network was 128, 231 and 10 carcasses for England, Scotland and Wales respectively. The majority of individuals saw less than five dead seals in total during all of their surveys.
In England and Scotland, approximately 80% of volunteers that saw dead seals identified the species of at least one carcass. Of dead seals identified to species level from: England, 82% were common seals and 18% were grey seals, The Wash (i.e. Norfolk and Lincolnshire), 94% were common and 6% grey seals, Scotland, 93% were grey seals and 7% were common seals. In Wales, all volunteers gave information on species identification. The situation in Wales is markedly different to that in England and Wales where the seal population is almost entirely grey, apart from rare exceptions in the north.
The quality of information retrieved on the dead seal reports from volunteers was variable. In England, approximately 70% of active volunteers gave an exact body length measurement on at least one carcass and over 90% gave some information on the estimated size or age of the seal. In Scotland, approximately 83% of active volunteers gave an exact body length measurement and almost 95% gave some information on the estimated size or age of the seal. None of the Welsh volunteers gave exact information on body length measurements although approximately half gave some details of estimated size or age of the seal.
Information Distribution and Media Management
The availability of accessible and up-to-date information on the status of the PDV epizootic helped an open exchange of information with the public and provided a useful tool for dealing with media enquiries.
Electronic information proved the most convenient and effective method of distribution during the epizootic. The speed and ease of electronic communication was noted in contrast to the situation in 1988 where this was not available and rapid dissemination of information was more problematic. Information for each status report was integrated by the Institute of Zoology and passed to the Sea Mammal Research Unit for formatting and posting on their Web page (See Appendix 5.5). Between 14th August 2002 and 6th May 2003 a total of 24 reports were posted, giving a summary of the numbers of carcasses found by species (where known) in England, Scotland, Wales and Northern Ireland separately. In addition maps were created with the numbers found in each county. When laboratory results indicating the numbers of PDV positive and negative animals, by species, were known these were also included in the reports. A standard layout for status reports was developed during the first weeks of the outbreak to allow easy consultation and comparison between updates. Status reports were also disseminated by list serves to local authority representatives and systematic volunteer networks around the UK on a regular basis. It was felt that this helped to maintain the Phocine Distemper Virus Epizootic Investigation 2002/2003 48 profile of the project and the individuals’ interest as part of the investigation. Electronic reports provided a useful reference to field press and media enquiries where detailed numerical information was required.
Integration of the UK status reports into European reports by the Common Wadden Sea Secretariat enabled rapid dissemination of information about the entire epizootic. Pan European communication throughout the epizootic was optimal and played an important role in enabling the UK to prepare for the outbreak reaching its waters.
Members of the public and media were often directed to the “Frequently Asked Questions” (see Appendix 2.5) sections and others available on the Defra website. These documents provided a useful source of information providing answers to the majority of caller concerns relating to responsibility and methods for carcass disposal and health and safety issues.
Video conferences during the early stages of the epizootic enabled the exchange of information and discussion of management options between governmental representatives and the project co-ordinators. The flexible and dynamic approach taken was valuable and allowed rapid response and resolution to issues as they arose.
The Public Relations department at the Zoological Society of London provided invaluable assistance with preparation and distribution of the volunteer appeal press release at short notice. The department was also responsible for fielding enquiries from radio and television interviews during the epizootic. Pre-recorded radio interviews to regional stations were most commonly requested and undertaken. At the outset of the PDV epizootic, national media interest was at its height. Subsequently, the outbreak became a rolling news piece through regional media as presence of the virus was confirmed in new areas of coastline.
See Appendix 5.2-5.3 for details of the interview and coverage log of media pieces regarding the PDV epizootic. A collection of media pieces and articles relating to the 2002 PDV epizootic have been archived and will be available on file as a reference source.
The SMRU also dealt with a number of press enquiries between August 2002 and October 2002 although these were far fewer than expected from the experience of 1988. Many factors may have accounted for this difference; other major news stories were happening in 2002; in contrast to 1988 the cause of the outbreak was known and there were many more parties and research groups involved in the response which enabled specific and local enquiries to be dealt with by the most appropriate group.
SAC Inverness staff gave interviews and supplied detailed local information for BBC Radio Scotland, Grampian television, The Daily Mail, The Orcadian (Orkney newspaper) and The Shetland Times. Marine Environmental Monitoring representatives in Wales gave no interviews during the PDV epizootic. In the absence of confirmed cases of PDV in Wales, the local media interest was not as intense as in the remainder of the UK. In Northern Ireland, Dr. Seamus Kennedy of the Department of Agriculture and Rural Development, gave several radio and TV interviews and dealt with a number
Phocine Distemper Virus Epizootic Investigation 2002/2003 49 of media enquiries. The majority of enquiries received from both the press and public were very supportive of the overall response to the outbreak.
Provision of up-to-date information on the PDV epizootic via the National Seal Hotline was also thought to have been worthwhile and used by a number of callers on a regular basis. However quantification of the proportion of callers who accessed electronic versus telephone information is not possible. National co-ordinators responded to requests for information and articles from wildlife organisations with articles for their readers (e.g. Mammals Trust UK, Lifewatch, BDMLR). NERC published an article in their magazine Planet Earth (Hall and Stephenson, 2002), reporting on the status of the epizootic at the time and publicising the National Seal Hotline number.
Phocine Distemper Virus Epizootic Investigation 2002/2003 50 • Discussion
Firstly, it must be stressed that the 2002 PDV epizootic represented a relatively straightforward wildlife disease investigation in many respects. This is principally due to a number of factors:
1) a prior knowledge of the aetiology of the disease. 2) the ability to make predictions on the onset and pattern of mortality from the 1988 epizootic. 3) the three month period for planning between first confirmed case in Europe and the first case in the UK. Nonetheless, funding for the PDV investigation was not confirmed until mid-August 2002 (about the same time that the first UK case of PDV infection was diagnosed), which caused a considerable delay in the ability to implement these plans. 4) large and easily identified carcasses of a species perceived favourably in the majority of instances by members of the public. 5) the experience that organisations such as the Institute of Zoology have developed over a 10-year period investigating endemic and epizootic wildlife disease in UK. This experience includes establishing or developing investigation protocols, developing diagnostic and reporting networks, establishing links to other organisations, database management and managing public appeals. 6) widespread co-operation and assistance provided by voluntary organisations (particularly RSPCA and BDMLR) prior to and throughout the investigation.
Despite these obvious advantages, the investigation of the epizootic presented a number of anticipated and novel challenges. For example, the inability (due to Health and Safety concerns) to ask volunteers or members of the public to handle carcasses resulted in a relative paucity of good quality data on the species and sex or dead carcasses compared to during the 1988 PDV epizootic. Also, the priority given to cetacean post mortem investigations and strandings research in recent years led to a lack of good quality data on baseline stranded seal mortality to compare with that seen during the epizootic.
It should be stated from the outset that the contribution of voluntary organisations played a major role in the overall success of this investigation. In particular, the RSPCA (and Scottish SPCA in Scotland), and the British Divers Marine Life Rescue (BDMLR) throughout the UK, while by no means the only voluntary organisations assisting with the investigation, warrant particular acknowledgement for their respective contributions. In addition to the key welfare role involving the rescue and rehabilitation of sick seals (predominantly within The Wash region), the RSPCA also forwarded calls from the RSPCA 24hr hotline, provided advice on establishing and maintaining a national hotline (including the offer to host the National Seal Hotline from the outset of the investigation if necessary), assisted with carcass collection, and provided Defra with useful briefing materials at the beginning of the investigation. The team of RSPCA veterinarians based at the RSPCA Wildlife Hospital in Norfolk also diagnosed the first (index) case of PDV in the UK shortly before the Defra-funded investigation was underway, and contributed all data and tissue samples derived from their own Phocine Distemper Virus Epizootic Investigation 2002/2003 51 investigations of sick and dead seals admitted to the Norfolk Wildlife Hospital. The professionalism and dedication of these RSPCA inspectors, veterinarians, veterinary nurses and support staff was undoubtedly a critical component of the UK response to the PDV epizootic. As a reciprocal arrangement, a full set of all centralised data derived from the Defra-funded PDV investigation, including full post mortem reports, results of diagnostic tests and other pathological data will be made available to the RSPCA for future reference.
In addition to the RSPCA, the BDMLR also provided considerable assistance with carcass reporting and collection, and members of BDMLR provided a significant proportion of the volunteers used to monitor stranded seal mortality during this investigation. Veterinarians from BDMLR also assisted with post mortem examinations of seal carcasses, and many BDMLR members assisted the work of the RSPCA in a seamless manner. The overall benefit to this investigation of these voluntary organisations working closely together and, wherever possible, assisting scientists involved in the Defra-funded investigation cannot be understated.
Epidemiology of the 2002 UK PDV Epizootic
The recorded UK dead seal counts during the 2002 epizootic, together with aerial census data obtained for east coast common seal colonies in 2002 and 2003, demonstrated that the impact of the UK PDV epizootic was greatest within The Wash common seal population where 13-18% of the population was estimated to have died due to the virus. A common seal from The Wash population that presented as the first (index) case of PDV infection in UK seals was found dead in mid-July. The number of dead seal reports from The Wash increased significantly thereafter reaching a peak in mid-September of 425 dead seal reports per week. By the end of December 2002 the numbers of dead seals reported within The Wash had returned to background (non- epizootic) levels.
In other large common and grey seal colonies/populations within Scotland, Northern Ireland and Wales, no epizootic-type mortality was detected based on the monitoring and quantification of dead seal reports accompanied, in some areas, by aerial census data. A number of PDV-positive seals were identified in Western and Eastern Scotland, Orkney and in Northern Ireland, and so this absence of mortality cannot be due to exclusion of PDV from these regions. However, no cases of PDV were identified in Shetland, or in the predominantly grey seal colonies within Pembrokeshire, Wales and in Cornwall, England, suggesting that these areas may be the beyond the geographical limits of PDV transmission during the 2002/2003 PDV epizootic.
The timing of the UK PDV epizootic during 2002 is likely to be a significant factor influencing both PDV exposure and associated mortality rates. Since peak haul-out densities in UK common seal colonies occur in June and July, and then again in September for the moult, maximum viral transmission of PDV between individuals is likely to occur during these periods. In The Wash, where the UK epizootic started, the first case of PDV infection was identified in mid-July (during pupping/breeding), and the peak of the epizootic mortality occurred during September (the moult) in this region. The epizootic in The Wash quickly burnt-out during October when the last cases
Phocine Distemper Virus Epizootic Investigation 2002/2003 52 of PDV infection and phocine distemper were identified. In contrast, the first case of PDV infection in Scotland was not identified until much later in mid-September and subsequent numbers of Scottish dead reports, common seals infected with PDV, and common seals dying of phocine distemper (between September 2002 and January 2003) were much lower than had occurred in The Wash. Since the average common seal haul- out densities would have been much lower between October and January in Scotland than they were in The Wash between July and September, it likely that the (density dependent) rates of viral transfer between individuals were lower in Scotland despite the fact that Scotland accounts for approximately 90% of the total UK common seal population.
As was the case in 1988, grey seals appeared resistant to the effect of the PDV virus. Of the 72 UK grey seal carcasses tested during the epizootic, only 10 were positive suggesting that only a proportion of UK grey seals became infected with PDV during the epizootic. Of these 10 positives, none were considered to have died due to PDV. The confirmation of PDV infection in UK grey seals combined with their high resistance to PDV-induced disease and mortality and their greater geographic range for foraging including the use of multiple haul-out sites (McConnell et al. 1999), has led many scientists to suspect that they have a major role to play as vectors in the dissemination of PDV between common seal colonies.
Comparative Epidemiology of the 1988 and 2002 PDV Epizootics
There are a number of similarities between the 1988 and 2002 epizootics, both on a European and UK scale. The timing of the two European epizootics were similar, although the 2002 epizootic started a few weeks later in the year (end April/early May) than the 1988 epizootic. Maximum viral transfer is likely to occur during periods of peak haul-out densities, which in UK common seals occurs in June/July (for pupping/breeding) and again in September (for moulting). This delay, even by a few weeks, in the arrival and subsequent dispersal of PDV in UK seals in 2002 may have had a role to play in the lower levels of PDV-related common seal mortality observed in 2002 compared to 1988.
Curiously, both 1988 and 2002 PDV epizootics began on Anholt Island in the Danish Kattegat. The spatial and temporal progression of the epizootic into the Skaggerak, North Sea, Waddensea and Southern Baltic were also similar in 1988 and 2002. Common seals distributed within the most northerly part of their range (Northern Norway and Iceland) appeared resistant to PDV-associated epizootic-type mortality in both 1988 and 2002. Within the UK, the index cases in both 1988 and 2002 epizootics were located within The Wash population of common seals that suffered epizootic mortality in both years. Within the UK and across Europe, grey seals appeared to be resistant to phocine distemper, although many were infected with the virus. No grey seals were considered to have died due to phocine distemper during this investigation. Since grey seals are known to range over much greater distances and use a number of different haul-out sites, many scientists now suspect grey seals may play a major role in the transmission and epidemiology of PDV in European seals.
Phocine Distemper Virus Epizootic Investigation 2002/2003 53 One apparent difference between 1988 and 2002 was in the level of population decline in some common seal populations in Scotland. In 1988 common seals suffered significantly lower mortality in Scotland, compared to The Wash and other parts of Europe, with the more northerly common seal colonies experiencing the lowest overall levels (as a percentage of the total estimated population size). In 2002, based on aerial surveys and dead seal counts, there was no detectable increase in mortality within any Scottish common or grey seal colonies. The reasons for these differential rates of mortality in UK common seals from different regions are incompletely understood. It is not known whether they relate to different levels of PDV exposure, or whether some (more northerly) common seal populations have a greater innate immunity to PDV resulting in lower levels of mortality in PDV infected seals, or a combination of both. As already discussed, a possible factor influencing lower levels of PDV exposure could include seasonal variations in seal-haulout densities during periods of PDV presence within specific colonies. Possible factors influencing spatial variation in common seal resistance to PDV-induced mortality could include regional variation in immunosuppressive and environmentally persistent pollutant levels (such as PCBs and organochlorine pesticides), or spatially explicit variation in levels of innate (rather than acquired) immunity to PDV resulting from differences in historical or evolutionary PDV exposure. Further research is necessary to investigate these areas of scientific uncertainty, and to predict the likely frequencies and impacts of future PDV epizootics in European seals.
Pathological Investigations
Necropsies were performed by a number of veterinary pathologists around the UK during the course of the epizootic, maximising the number of carcasses that it was possible to examine. The creation of a standardised examination and sampling protocol (essentially a standard pinniped protocol already in use within the UK) and electronic reporting pro forma facilitated simple integration of information and test results from multiple sources.
In general, the lesions found in common seals that died of phocine distemper were remarkably similar to those described during the 1988 epizootic (see Kennedy 1998). This includes not just the gross and histopathological findings, but also the range of typical secondary bacterial and fungal pathogens identified in affected seals. This is perhaps not surprising, since the strains of PDV involved in both 1988 and 2002 epizootics were very similar on molecular (genetic) characterisation (Jensen et al. 2002). In both 1988 and 2002 epizootics, grey seals appeared remarkable resistant to PDV and, even though infection was confirmed in a number of grey seal carcasses, no definitive cases of fatal phocine distemper were confirmed in UK grey seals in either 1988 or 2002.
A point of note is that many seals, and particularly those at the very beginning of the epizootic in The Wash had acute interstitial pneumonia (usually accompanied with interstitial/mediastinal emphysema) and possibly lymphodepletion as the principal and most consistent lesions. Inclusion bodies and syncytia were usually absent in these tissues. The majority of cases of fatal distemper therefore did not have the “classical” suite of lesions associated with canine distemper in seals (Kennedy et al. 2000) or
Phocine Distemper Virus Epizootic Investigation 2002/2003 54 domestic dogs (Dungworth 1993) including widespread syncytia, eosinophilic inclusions bodies within epithelia and lymphoid tissue, and demyelinating non- suppurative meningoencephalitis. Without the back-up of diagnostic testing for presence of PDV in tissue samples, the diagnosis of phocine distemper would be difficult to ascribe with certainty in many cases. The frequency and severity of interstitial and mediastinal emphysema in cases of phocine distemper without evidence of secondary bacterial or mycotic bronchopneumonia confirms that the primary viral (interstitial) pneumonia was sufficient to induce these emphysematous lesions.
In common seals from The Wash, around 90% or more of common seal carcasses infected with PDV were diagnosed to have died of phocine distemper. Of the 27 common seals tested for PDV in Scotland, only 12 (44%) were determined to be infected with PDV in Scotland and only 6 (50%) died of PDV infection (i.e. fatal phocine distemper). Although this apparent lower susceptibility to fatal disease from PDV infection in Scottish common seals is consistent with the suggestion that Scottish common seals could have a higher innate (possibly immunogenetic) resistance to phocine distemper, a much larger sample size would be needed to test this hypothesis robustly. Post-epizootic serological studies to evaluate the proportions of common seals in different colonies that were exposed to PDV and survived would be a useful tool to investigate whether differential rates of common seal mortality were predominantly due to differences in PDV exposure or PDV-induced mortality.
Positive antibody titres to feline herpesvirus were found in 25/61 (41%) common seals comprising 3/21 (14%) pups, 9/22 (41%) juveniles, 1/2 (sub)adults (50%), and 12/16 (75%) adults tested. The results are consistent with an endemic herpesvirus infection within common seals in the North Sea. The increasing prevalence of antibodies with age suggests that horizontal transmission is important in the epidemiology of phocine herpesvirus in common seals. Both phocine herpesvirus-1 (PHV-1) and toxoplasma (T. gondii) are potential secondary pathogens in phocine distemper (e.g. Kennedy 1998) and some hepatic and CNS lesions seen in fatal phocine distemper cases were consistent with systemic PHV-1 and Toxoplasma sp. infections.
The pathological investigation of seal carcasses was an integral and essential part of the investigation. These examinations not only permitted the identification and progression of the virus within specific common and grey seal colonies, but also facilitated a greater understanding of the nature of the disease itself. Furthermore, the extensive range of frozen and formalin-fixed samples taken during seal carcass examinations, forms part of a valuable and extensive National Marine Mammal Tissue Archive permitting a range of parallel research activity into other aspects of seal biology. The collaborative approach adopted between the research institutions and animal welfare organisations greatly added to the volume and quality of material collected during the epizootic, the exchange being beneficial to both parties. Collaboration between the Institute of Zoology and the RSPCA Norfolk Wildlife Hospital was particularly close and productive during the epizootic. The opportunity for teaching wildlife pathology to veterinary undergraduates and post-graduates on wildlife pathology was an additional and valuable output of the project.
Phocine Distemper Virus Epizootic Investigation 2002/2003 55 The use of temporary cold store facilities at the Peaceful Pets Crematorium provided a highly successful, cost effective and convenient method for collection, examination and on-site disposal of a large number of carcasses from The Wash. Pathologists from the Institute of Zoology were able to visit the facility for necropsies on large numbers of seals, taking of biometric measurements and sampling for genetics studies. The use of large-scale freezer facilities for temporary storage of seal carcasses was adopted in The Netherlands and other parts of Europe. Representatives from the Institute of Zoology assisted with the necropsy of over two hundred seals in Texel, Netherlands, and were able to appraise this approach to an investigation. Organisation of a mass necropsy session increased the volume and quality of information that could be collected for both demographic data and pathological investigations. The operation of a series of strategically located temporary cold store and freezer facilities is highly recommended for the investigation of future wildlife epizootics in the UK.
Molecular Diagnostic Testing
The availability of sophisticated molecular diagnostic testing represents a significant advance in technologies since the 1988 PDV epizootic. During the 1988 epizootic diagnosis of PDV infection was based on the results of gross pathology and histopathological examination. The use of these contemporary molecular diagnostic tools such as RT-PCR and immunohistochemistry greatly improved the reliability of viral identification in tissue samples collected during post mortem investigations. Nonetheless, logistical problems with throughput of sample testing occurred as a consequence of limited staffing levels and reagent availability at the laboratories involved during the project.
Future research investigations need to address capacities for bulk sample testing under epizootic conditions and should explore whether resources, particularly staffing levels, can be increased to deal with the demand. The practicality of arranging short-term increases in highly trained laboratory staff however remains problematic and may need to be addressed separately.
Opportunistic Dead Seal Reporting (National Seal Hotline)
The use of the National Seal Hotline during the 2002 PDV epizootic was a relative success and a similar arrangement is recommended for the management of reporting during future wildlife disease outbreaks. Provision of a single number for all seal related concerns gave a simple and straightforward system for use by members of the public. Callers were able to use the automated touch-tone system with only a very small number of messages mistakenly being transferred to the incorrect organisation as a consequence of user error. High caller compliance was experienced from those using the system with the project receiving a minimal number of complaints about the contact process. Even at the height of the epizootic, the system had capacity to deal with call volume. Employment of Greenland Interactive Ltd., as a commercial organisation, to manage the telecommunications system provided efficient, rapid and reliable service.
In England, publicity of the National Seal Hotline was effective and the vast majority of callers used this number. In Scotland, Wales and Northern Ireland a greater proportion
Phocine Distemper Virus Epizootic Investigation 2002/2003 56 of calls were received by the organisation direct and not through diversion from the National Seal Hotline. In many instances, this was because pre-existing direct telephone numbers were already familiar to a proportion of callers, particularly land wardens, etc. Nevertheless, the National Seal Hotline was advertised in the press in all regions and was used by the public around the UK. The high call volume experienced during the PDV epizootic reflects the high level of concern within the general public for wildlife population health, environmental and animal welfare issues in the UK.
It is clear that the number of dead seal reports in The Wash (North Norfolk and Lincolnshire) acquired through the National Seal Hotline overestimated common seal mortality during the epizootic in The Wash population. Although a number of causes may explain this discrepancy, it is hard to ignore the likelihood of considerable duplication in Seal Hotline reports at the height of the epizootic. Whilst every effort was made to exclude obvious duplicate reports at the time of recording, differentiation between seal carcass location descriptions, often based on features of local geography, was difficult during the peak of mortality in The Wash. The lack of carcass marking, due to health and safety concerns, also exacerbated the likelihood of duplicate seal reports. In contrast, mulitple reports of individual seal carcasses in areas of low overall mortality were relatively straightforward to detect. The quality of data on dead seal reports retrieved by the National Seal Hotline was also variable and sometimes low in quality. The majority of callers left information on the approximate location of the dead seal, the date found and their contact details. However, information on species identification, size and carcass condition was often unavailable. Therefore, although the National Seal Hotline worked very efficiently for receiving seal reports and disseminating information to the general public, it was not useful for accurately quantifying seal deaths in areas experiencing epizootic mortality.
Systematic Dead Seal Reporting (Volunteer Appeal)
It was generally considered that the attempt to recruit and deploy volunteers from interested members of the public and wildlife-associated organisations to improve upon the quality of data derived from the National Seal Hotline met with limited success. Specifically, there was a relatively low-uptake of initial respondents to the volunteer appeal, which translated into an even lower number of “active” volunteers. There was a clear lag between the onset and peak of seal mortality and the recruitment of some volunteers, and the methodology and quality of data derived from active volunteers varied considerably. The recruitment, maintenance and administration of the systematic volunteer programme proved very labour intensive.
The extent of the “drop off” experienced through stages of recruitment was considerable; approximately 50% of initial volunteer contacts went on to participate in at least one active survey; of these, approximately half saw at least one dead seal; of these; species identification was provided in approximately 80% of cases.
Members of the public may have been dissuaded from volunteering or from continuing with active reports because (a) of the long term commitment and frequency of surveys required; (b) the appeal involved monitoring of dead seals and not live seals, which would have been more charismatic; and (c) of the low probability of finding a dead seal
Phocine Distemper Virus Epizootic Investigation 2002/2003 57 dependent on date and region. Considerable emphasis was placed on maintaining communication with the volunteer networks in an effort to foster enthusiasm and interest in survey work and to stress its importance. Electronic list serves proved the most effective means of updating volunteers on a regular basis and the dedicated e-mail accounts were a popular and successful method for receiving reports.
It is important to recognise the lag period between the outset of the appeal for volunteers and (1) contacts from those interested in participating in the scheme and, (2) receiving first surveys from active volunteers. This underlines the urgent need for a pre- existing strategy (e.g. guidelines and organisation contacts) and identified responsibility for co-ordinating organisation(s) during wildlife mass mortality events in the future. Such a situation could be achieved if a network of volunteers (wildlife health wardens) was established for the reporting of diseased or dead wild animals on a continuous basis. This would have the added advantage of building up a picture of “background” levels and types of disease with a known degree of observer effort.
Difficulties arose with some volunteers in conveying the importance of systematic data reporting, particularly for the reporting of both positive and negative findings. A number of volunteers in effect gave high quality “opportunistic” reports, using the information within the guidelines to identify species and obtain measurements, rather than systematic coast surveys.
The volunteer scheme was useful for increasing the “quality” of dead seal reports and for provision of “negative” sightings information for mathematical modelling of the PDV epizootic. However the quantity (and in some cases quality) of data obtained by the volunteer networks was less than originally anticipated, although the overall seal mortality was also considerably lower in 2002 than had occurred in 1988. If possible, an analysis of the relative worth of recognised volunteer reports and Seal Hotline reports will be conducted in the future to better evaluate this type of reporting activity. It is recommended that in the future, this method of collecting data (using volunteers) during a wildlife epizootic would be replaced or complemented with a scheme likely to provide higher quality and quantity of data relative to the administrative effort its implementation would require (See Recommendations for Investigation of Future Wildlife Epizootics).
Nevertheless, the scheme demonstrated that many members of the public were concerned and willing to donate their time and effort to assist during the outbreak. Volunteer appeals for assistance with future wildlife health study should be considered and appraised on an individual basis. Appeals that require reporting of positive observations only (e.g. sighting of live or dead animal of particular species), relatively infrequent recording of observations, and that can be organised in advance, rather than during an outbreak, may be most appropriate.
Carcass Disposal
Following the experience of the recent UK foot and mouth virus epizootic, Defra rapidly developed guidelines for seal carcass disposal to Local Authorities and private landowners. These guidelines were also accessible through the Defra website. The
Phocine Distemper Virus Epizootic Investigation 2002/2003 58 National Seal Hotline was very effective for rapid reporting of seal carcasses, which at the height of The Wash epizootic accounted for several hundred seal reports per week. This placed enormous pressure on national strandings co-ordinators, particularly within England, to find and contact the relevant Department for beach cleaning/environmental health in order to dispose of the large numbers of carcasses reported. Initially, a period of time was needed to develop a database for appropriate contact persons within each Local Authority so that stranded seal reports could be disseminated quickly. With so many seals in such a short period of time, there was an inevitable delay in the process of carcass disposal within the early period of the epizootic. Other factors including variable resources, land access and position, the number of carcasses, public/private land ownership etc. would also undoubtedly have affected the efficiency of carcass disposal.
In general, however, the disposal of carcasses was successful. This was facilitated by the peak of the seal mortality being confined to The Wash area which benefits from good beach access and proximity to high-quality incineration facilities. Had a similar scale of seal mortality occurred in the larger and more remote seal colonies within Scotland, with associated lack of suitable incineration or rendering facilities, the scale of the problem of carcass disposal would have been considerably greater. Integral to contingency planning for future disease epizootics/mass mortality events should be the provision of adequate resources for carcass disposal across all UK regions.
Phocine Distemper Virus Epizootic Investigation 2002/2003 59 • Recommendations for the Investigation of Future Wildlife Epizootics
The success of the investigation to date is largely due to strong collaboration between government, welfare organisations (RSPCA and BDMLR), non- governmental organisations and research institutions. An effective response was achieved since the organisations involved have a history of working together on the long-term Defra-funded UK Cetacean Strandings project. The exchange of information, samples and diagnostic support benefits both research institutions and animal welfare organisations and should be an integral part of similar wildlife disease investigations in the future.
The National Seal Hotline proved a relative success for the collection of opportunistic dead seal reports. The use of a single hotline number is recommended for investigating and managing future wildlife disease epizootics, in particular for locating carcasses for examination and/or disposal, but not for obtaining quantitative and reliable seal mortality data. Guidelines could be distributed to wildlife and rescue organisations describing the information required from seal carcasses and appeals should be made for details from all opportunistic seal sightings.
The systematic collection of data through the volunteer appeal had more limited success. Schemes for data collection using systematic volunteer surveys would either not be repeated during a future epizootic, or would be refined to improve both data quality and quantity. The use of recognised volunteers may have the potential to provide improved quality of data reporting and a better estimation of overall seal mortality, but the scheme used here clearly needs to be improved upon to achieve these goals. This approach could possibly be improved with a longer lead-in time and through establishing or maintaining long-term wardens. Appeals for volunteer assistance with investigations of wild animal health and disease in the future should be assessed on an individual basis.
Recommend the use of regional cold store or freezer facilities in the future, particularly in key areas close to high seal densities. In some areas of Europe a greater proportion of seal carcasses were collected and examined as part of the investigation. A proportion of fresh carcasses were examined immediately in each area and the remainder were stored in freezer facilities for mass sampling or necropsy at a later date.
This approach increased the volume and quality of data that could be collected for both demographic and pathological investigations. In addition, the use of multiple cold store or freezer facilities would provide Local Authorities and private landowners with a simple option for carcass disposal, thereby perhaps increasing the speed and efficiency of removal from the beach. This would have the additional benefit of reducing the likelihood of duplicate dead seal reports. Responsibility for Phocine Distemper Virus Epizootic Investigation 2002/2003 60 the costs of disposal would need to be clarified. Costs could be met as part of the project, or a charge could be made per unit weight for disposal invoiced to the Local Authority. Further research is required to explore resource availability for this type of arrangement in advance of another wildlife disease outbreak.
The need exists for a defined UK strategy for the investigation of UK wildlife epizootics in the future. The creation of a long-term monitoring programme to determine background levels of disease and mortality would facilitate the optimal response during an epizootic and maximise the benefit of such investigations by providing high quality baseline data for comparison with findings acquired during an epizootic. The absence of a co-ordinated dead seal reporting structure, in contrast to that for cetaceans, meant that reporting systems (e.g. volunteer network) and contacts (e.g. Local Authorities) had to be developed at the time of the epizootic. A preferable system would have lower level funding for background monitoring of seal mortality in non-epizootic years (maintaining the dedicated seal hotline) and facilitating post mortem examinations of small numbers of seal carcasses. Optimal response for the investigation of epizootics would best be achieved by creation of a pre-existing network. Agreement as to the availability of higher level funding would be in place should an epizootic occur. Consequently protocols, guidelines and contacts with local councils and organisations etc. would already be in place at the outset of a mass mortality event. Permanent skilled staff would be available for initial site visits and assessment, contingency plans ready for implementation as necessary. As part of this process, centralised and co-ordinated wildlife disease investigation centre(s) should be appointed or developed with expertise to cover all wildlife species within the UK.
The epidemiological factors influencing lower levels of common seal mortality in Scotland (and other parts of Northern Europe), despite having some of Europe’s largest common and grey seal populations, are incompletely understood. Future research activities should seek to address the factors influencing differential rates of PDV-induced mortality in UK and European seals, including possible (immuno)genetic and toxicological factors. For example, post-epizootic serological monitoring of common seal survivors would help to address whether different mortality rates between some common seal colonies were predominantly due to differences in the level of PDV exposure, or level of PDV-induced mortality, or a combination of both. These avenues of research are also fundamental to predictions about the frequencies and impacts of future European PDV epizootics.
The long-term impacts of future PDV epizootics on European seal populations are difficult to predict. It is recommended that adaptive epidemiological models, increasing in sophistication as the latest biological data becomes available, continue to be developed to enable accurate predictions of the likely frequencies and impacts of future PDV epizootics on European seal populations.
Phocine Distemper Virus Epizootic Investigation 2002/2003 61 • Investigation Outputs
Conference / Workshop Attendance
• Attendance of the International symposium on the management of North Sea common and grey seal populations, EcoMare Wadden Sea Information Center, 29 - 30 November 2002, Texel, The Netherlands. • Attendance of mass seal necropsy session, 17–19 February 2003, Texel, The Netherlands, to assist with sample collection according to protocol and foster international contacts and collaboration. • Attendance of Phocine Distemper Virus Epidemic March 2003 workshop at the European Cetacean Society, Gran Canaria, and presentation of findings to date from the UK. “The 2002 Phocine Distemper Virus Epidemic in the United Kingdom”. • Poster presentation for the 17th Annual Conference of the European Cetacean Society, Gran Canaria, March 2003. "A spatial investigation of the 2002 Phocine Distemper Virus outbreak affecting seals in Scottish waters.” • Presentation titled “The UK 2002 Phocine Distemper Virus (PDV) Epizootic” at the British Veterinary Zoological Society Autumn Meeting, Infectious Diseases of Exotics, November 2003. • Presentation titled “The UK Phocine Distemper Epizootic 2002” at the RVC Zoological Society Symposium, The Role of Vets in International Zoo and Wildlife Conservation, November 2003. • Poster presentation at the 15th Biennial Conference on the Biology of Marine Mammals Greensboro, North Carolina, December 2003. “Investigating the Impact of the 2002 Phocine Distemper Epizootic in the United Kingdom.”
• Parallel Research
• Serosurvey of seal sera by Veterinary Conservation Medicine student (Hannah Leyland) under the direction of Professor Malcolm Bennett. Screen for antibody to orthopoxvirus, herpesvirus, parapoxvirus, toxoplasma and neospora. (Liverpool University Veterinary School). • NERC funded epidemiological modelling of 2002 PDV epizootic in Europe (Institute of Zoology/SMRU-St Andrews University/ Cambridge University).
• Future Research
• Relationships between intra- and inter-population microsatellite/MHC variation and PDV susceptibility (Institute of Zoology/Gothenburg University, Sheffield University, Cambridge University). Funding application in process. • Participation in seal serosurvey investigation with the Institute of Zoology and Erasmus University, Rotterdam, The Netherlands. • Participation in multi-author European perspective paper on the PDV epizootic 2002 organised by Dr Tero Harkenon at the Swedish Museum of Natural History. Phocine Distemper Virus Epizootic Investigation 2002/2003 62 • Contribution of samples to research on ageing techniques and teeth composition by Dr Beth Mackey, University of Aberdeen and Tero Harkenon at the Swedish Museum of Natural History. • Contribution of samples to Dr David Williams, University of Cambridge for ophthalmological research. • Contribution of samples to Andy Rutson-Edwards, Anglia Polytechnic University, for his research on “The Place of ‘Red’ Seals in the Ecology of Walton Backwaters”.
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Phocine Distemper Virus Epizootic Investigation 2002/2003 76 Phocine Distemper Virus Epizootic Investigation 2002/2003 77 Appendix 1 – Organisation Contact Directory
1.1 Collaborators and Participating Organisations
Institute of Zoology, Zoological Society of London, Regent’s Park, London, NW1 4RY T: +44 (0)20 7449 6672 F: +44 (0)20 7584 1457 E-mail: [email protected] Website: http://www.zoo.cam.ac.uk/ioz
Dr John Baker, Department of Veterinary Pathology, University of Liverpool, Leahurst, Neston, Wirral, CH64 7TE
Institute of Animal Health, Ash Road, Pirbright, Surrey, GU24 ONF T: +44 (0)1483 232441 F: +44 (0)1483 232448 E-mail: [email protected] Website: http://www.iah.bbsrc.ac.uk
Marine Environmental Monitoring, Penwalk, Llechryd, Cardigan, SA43 2PS T: +44 (0)1348 875000 F: -- E-mail: [email protected] Website: http://www.strandings.com
Natural History Museum, Cromwell Road, London, SW7 5BD T: +44 (0)20 7942 5011 (Information) T: +44 (0)20 7942 5000 (Switchboard) E-mail: http://www.nhm.ac.uk/info/email.html Website: http://www.nhm.ac.uk
Quoile Countryside Centre, Environment and Heritage Service, 5 Quay Road, Downpatrick, County Down, BT30 7JB T: +44 (0)28 4461 5520 F: +44 (0)28 4461 2380 E-mail: [email protected] Website: http://www.doeni.gov.uk
Scotland SAC Inverness, Wildlife Unit, SAC Veterinary Science Division, Drummondhill, Stratherrick Road, Inverness, IV2 4JZ T: +44 (0)1463 243030 F: +44 (0)1463 711103 E-mail: [email protected] Website: http://www.sac.ac.uk
Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, St Andrews, Fife, KY16 8LB T: +44 (0)1334 462631 F: +44 (0)1334 462632 E-mail: [email protected] Website: http://www.smru.st-and.ac.uk
Veterinary Sciences Division, Department of Agriculture and Rural Development, Stormont, Belfast, BT4 3SD, Northern Ireland T: +44 (0)28 9052 5701 F: +44 (0)28 9052 5767 E-mail: [email protected] Website: http://www.dardni.gov.uk
Phocine Distemper Virus Epizootic Investigation 2002/2003 1 1.2 Other Related Organisations
British Divers Marine Life Rescue, Lime House, Regency Close, Uckfield, East Sussex, TN22 1DS, T: +44 (0)1825 765546 F: +44 (0)1825 768012 E-mail: [email protected] Website: http://www.bdmlr.org.uk
BBC Wildlife Magazine, Broadcasting House, Whiteladies Road, Bristol, BS8 2LR T: +44 (0)117 973 8402 F: +44 (0)117 946 7075 E-mail: [email protected] Website: http://www.bbc.co.uk
British Wildlife Rehabilitation Council, c/o RSPCA Wildlife Department, Wilberforce Way, Southwater, Horsham, West Sussex, RH13 9RS T: -- F: -- E-mail: General information [email protected] Website: http://www.bwrc.org.uk
U.K. Cetacean Network [email protected]
Chartered Institute of Environmental Health (CIEH), Chadwick Court, 15 Hatfields, London SE1 8DJ, United Kingdom T: +44 (0)20 7928 6006 F: +44 (0)20 7828 5866 E-mail: [email protected] http://www.cieh.org
Cornwall Wildlife Trust, Five Acres, Allet, Truro, Cornwall, TR4 9DJ T: +44 (0)1872 273939 F: +44 (0)1872 225476 E-mail: [email protected] Website: http://www.cornwallwildlifetrust.org.uk
Countryside Council for Wales, Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd LL57 2DW T: +44 (0)845 1306229 (Enquiry line) F: +44 (0)1248 355782 E-mail: [email protected] Website: http://www.cieh.org
Devon Wildlife Trust, Shirehampton House 35-37 St David's Hill Exeter EX4 4DA T: +44 (0)1392 279244 F: +44 (0)1392 433221 E-mail: [email protected] Website: http://www.devonwildlifetrust.org
Earthkind, Town Quay, Poole, Dorset, BH15 1HJ T: +44 (0)1202 682344 F: +44 (0)1202 682366 E-mail: [email protected] Website: http://www.earthkind.org.uk
English Nature, Northminster House, Peterborough, PE1 1UA, T: +44 (0)1733 455000 F: +44 (0)1733 568834 (Main Switchboard) T: +44 (0)1733 455101 F: +44 (0)1733 455103 (Enquiries Service)
Phocine Distemper Virus Epizootic Investigation 2002/2003 2 E-mail: [email protected] Website: http://www.english-nature.org.uk
Environment Agency, Rio House, Waterside drive, Aztec West, Almondsbury, Bristol, BS32 4UD T: +44 (0)845 9333111 (General Enquiry Line) T: +44 (0)800 807060 (Emergency Hotline) F: +44 (0)1454 624409 E-mail: [email protected] Website: http://www.environment-agency.gov.uk
E-Van Deliveries Ltd., C/o Thompson Packing & Mailing, Lancaster Road, Carnaby Industrial Estate, Bridlington, YO15 3QY T: +44 (0)1262 408505 F: +44 (0)1262 408506 E-mail: [email protected] Website: --
Greenland Interactive Limited, 4 Greenland Place, London NW1 0AP T: +44 (0)20 7428 4472 F: +44 (0)20 7428 4455 E-mail: http://www.greenland.co.uk/contact/index.cfm Website: http://www.greenland.co.uk
Hunstanton Marine Sanctuary, Southern Promenade, Hunstanton, Norfolk, PE36 5BH T: +44 (0)1485 522 576 F: +44 (0)1485 533 531 E-mail: [email protected] Website: http://www.sealsanctuary.co.uk
Mammals Trust UK, 15 Cloisters House, 8 Battersea Park Road, London SW8 4BG T: +44 (0)20 7498 5262 F: +44 (0)20 7498 4459 E-mail: [email protected] Website: http://www.mtuk.org
Marine Conservation Society, 9 Gloucester Road, Ross-on-Wye, Herefordshire, HR9 5BU T: +44 (0)1989 566017 F: +44 (0)1989 567815 E-mail: [email protected] Website: http://www.mcsuk.org
National Seal Sanctuary, Gweek, Cornwall, TR12 6UG T: +44 (0)1326 221 361 F: +44 (0)1326 221 210 E-mail: [email protected] Website: http://www.sealsanctuary.co.uk
Ordnance Survey, Customer Service Centre, Ordnance Survey, Romsey Road, Southampton, SO16 4GU T: +44 (0)8456 050505 Customer Services F: +44 (0)23 8079 2615 Customer Services E-mail: [email protected] Website: http://www.ordsurvey.gov.uk and http://www.getamap.co.uk
Ramblers Association, 2nd Floor Camelford House, 87-90 Albert Embankment, London SE1 7TW T: +44 (0)20 7339 8500 F: +44 (0)20 7339 8501 E-mail: [email protected] Website: www.ramblers.org.uk Phocine Distemper Virus Epizootic Investigation 2002/2003 3
Royal Society for Protection of Birds, UK Headquarters, The RSPB, The Lodge, Sandy, Bedfordshire, SG19 2DL T: +44 (0)1767 680551 F: +44 (0)1767 692365 E-mail: [email protected] Website: http://www.rspb.org.uk
Royal Veterinary College, Department of Pathology and Infectious Diseases, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA T: +44 (0)1707 666596 F: +44 (0)1707 652090 E-mail: -- Website: http://www.rvc.ac.uk
RSPCA Headquarters, Wilberforce Way, Southwater, Horsham, West Sussex, RH13 9RS T: +44 (0)870 3335 999 (Enquiries) +44 (0)870 55 55 999 (Emergency and Cruelty Helpline) F: +44 (0)870 7530 284 E-mail: [email protected] Website: http://www.rspca.org.uk
RSPCA Norfolk Wildlife Hospital, East Winch, Kings Lynn, Norfolk, PE32 1NR T: +44 (0)1553 842336 F: +44 (0)1553 842543 E-mail: [email protected] Website: http://www.rvc.ac.uk
Seal Conservation Society, 7 Millin Bay Road, Tara, Portaferry, County Down, BT22 1QD T: (0)28-4272-8600 F: (0)28-4272-8600 E-mail: [email protected] Website: http://www.pinnipeds.org
Sea Watch Foundation, 36 Windmill Road, Headington, Oxford, 0X3 7BX. United Kingdom. T: +44 (0)1865 764794 F: +44 (0)1865 764757 E-mail: [email protected] Website: http://www.seawatchfoundation.org.uk
Scottish National Heritage, 12 Hope Terrace, Edinburgh, EH9 2AS T: +44 (0)131 447 4784 F: +44 (0)131 446 2277 E-mail: [email protected] Website: http://www.snh.org.uk
Scottish SPCA, Braehead Mains, 603 Queensferry Road, Edinburgh, EH4 6EA T: +44 (0)131 339 0222 F: +44 (0)131 339 4777 E-mail: [email protected] Website: http://www.scottishspca.org
The Grange, Peaceful Pets crematorium, West Rudham, King’s Lynn, Norfolk, PE31 8SY T: +44 (0)1485 528 141 F: +44 (0)1485 528444 E-mail: [email protected] Website: http://www.peacefulpets.co.uk
The Hebridean Whale and Dolphin Trust, 28 Main Street, Tobermory, Isle of Mull, Argyll, PA75 6NU T: +44 (0)1688 302620 Phocine Distemper Virus Epizootic Investigation 2002/2003 4 F: +44 (0)1688 302728 E-mail: [email protected] Website: http://whales.gn.apc.org
The Mammal Society, 2B, Inworth Street, London SW11 3EP T: +44 (0)20 7350 2200 F: +44 (0)20 7350 2211 E-mail: [email protected] Website: http://www.abdn.ac.uk/mammal
The Maritime and Coastguard Agency, Tutt Head, Mumbles, Swansea, West Glamorgan, SA3 4HW T: +44 (0)870 6006505 (MCA Infoline) F: -- E-mail: [email protected] Website: http://www.mcga.gov.uk
The National Trust, London Central Office, 36 Queen Anne's Gate, London, SW1H 9AS T: +44 (0)870 609 5380 F: +44 (0)20 7222 5097 E-mail: [email protected] Website: http://www.nationaltrust.org.uk
The Trilateral Cooperation on the protection of the Wadden Sea, Common Wadden Sea Secretariat, Virchowstr. 1, D 26382, Wilhelmshaven, Germany T: +49 4421 9108 0 F:-- E-mail: [email protected] Website: http://cwss.www.de/
The Wildlife Trusts National Office, The Kiln, Waterside, Mather Road, Newark, Nottinghamshire, NG24 1WT T: +44 (0)870 0367711 F: +44 (0)870 0360101 E-mail: [email protected] Website: http://www.wildlifetrusts.org
University of Cambridge Veterinary School, Department of Clinical Veterinary Medicine, Madingley Road, Cambridge CB3 OES T: +44 (0)1223 337694 F: +44 (0)1223 337610 E-mail: [email protected] Website: http://www.vet.cam.ac.uk
Wildlife Information Network, House of Stratus, Thirsk Industrial Park, York Road, Thirsk, YO7 3BX T: +44 (0)20 7388 7003 F: +44 (0)20 7388 7110 E-mail: [email protected] Website: http://www.wildlifeinformation.org
Whale and Dolphin Conservation Society, Brookfield House, 38 St Paul Street, Chippenham, Wiltshire, UK SN15 1LY T: +44 (0)870 870 0027 F: +44 (0)870 870 0028 E-mail: [email protected] Website: http://www.dolphinsightings.org
WWF-UK, Panda House, Weyside Park, Godalming, Surrey GU7 1XR T: +44 (0)1483 426444 F: +44 (0)1483 426409 Phocine Distemper Virus Epizootic Investigation 2002/2003 5 E-mail: http://www.wwf-uk.org/sitehelp/feedback.asp Website: http://www.wwf-uk.org
1.3 English East Coast Local Authority Details
NORTHUMBERLAND
Berwick upon Tweed Borough Council Health Unit, Environment Directorate, Berwick upon Tweed Borough Council T: +44 (0)1289 301821 F: +44 (0)1289 330540 E-mail: -- Website: http://www.berwick-upon-tweed.gov.uk
Alnwick District Council Technical Services, Alnwick District Council T: +44 (0)1665 510505 F: +44 (0)1665 605099 E-mail: -- Website: http://www.alnwick.gov.uk/
Castle Morpeth Borough Council Environmental Services, Castle Morpeth Borough Council T: +44 (0)1670 535 000 F: +44 (0)1670 535 060 E-mail: -- Website: http://www.castlemorpeth.gov.uk/
Wansbeck District Council Environmental Health, Wansbeck District Council T: +44 (0)1670 843 402 F: +44 (0)1670 843 484 E-mail: [email protected] Website: http://www.wansbeck.gov.uk/
Blyth Valley Borough Council Planning and Environmental Protection Unit, Blyth Valley Borough Council T: +44 (0)1670 542 325 F: +44 (0)1670 542 390 E-mail: [email protected] Website: http://www.blythvalley.gov.uk/
TYNE AND WEAR
North Tyneside Council Environment Regeneration and Housing Directorate, Cleansing Services, North Tyneside Council T: +44 (0)191 200 88 99 F: +44 (0)191 219 24 55 E-mail: [email protected] Website: http://www.northtyneside.gov.uk/
South Tyneside Council Cultural and Community Services Department, South Tyneside Council T: +44 (0)191 427 1717 F: +44 (0)191 427 0469 E-mail: [email protected] Website: http://www.s-tyneside-mbc.gov.uk/
Phocine Distemper Virus Epizootic Investigation 2002/2003 6 City of Sunderland City of Sunderland, Community and Cultural Services, Culture and Tourism, Resorts T: +44 (0)191 553 2828 F: +44 (0)191 553 2831 E-mail: [email protected] Website: http://www.sunderland.gov.uk/
CLEVELAND
Hartlepool Borough Council Environment Section, Refuse and Cleansing, Hartlepool Borough Council T: +44 (0)1429 523333 F: +44 (0)1429 523663 E-mail: [email protected] Website: http://www.hartlepool.gov.uk/
Stockton-on-Tees Borough Council To arrange disposal of dead seals Care for our Area, Service Stockton, Stockton-on-Tees Borough Council T: +44 (0)1642 391959
Issues relating to Animal Welfare Environmental Health Unit, Service Stockton, Stockton-on-Tees Borough Council T: +44 (0)1642 391116 Website: http://www.stockton.gov.uk
Redcar and Cleveland Borough Council Neighbourhood Services, Redcar and Cleveland Borough Council T: +44 (0)1642 477 800 F: +44 (0)1642 494541 E-mail: -- Website: http://www.redcar-cleveland.gov.uk
DURHAM
District of Easington Council Environmental Services, District of Easington Council T: +44 (0)191 527 0501 F: +44 (0)191 527 2416 E-mail: -- Website: http://www.easington.gov.uk
NORTH YORKS
Scarborough Borough Council Department of Technical Services, Scarborough Borough Council T: +44 (0)1723 232 459 F: +44 (0)1723 385 698 E-mail: [email protected] Website: http://www.e-sbc.co.uk
HUMBERSIDE
East Riding of Yorkshire Council Environmental Services, East Riding of Yorkshire Council T: +44 (0)1482 887700 F: +44 (0)1482 395055 E-mail: -- Website: http://www.eastriding.gov.uk Phocine Distemper Virus Epizootic Investigation 2002/2003 7
North Lincolnshire Council Environmental Public Protection, North Lincolnshire Council T: +44 (0)1724 297 602 F: +44 (0)1704 297899 E-mail: -- Website: http://www.northlincs.gov.uk
North East Lincolnshire Environmental Services, North East Lincolnshire T: +44 (0)1472 323423 F: +44 (0)1472 324302 E-mail: -- Website: http://www.nelincs.gov.uk
LINCOLNSHIRE
East Lindsey District Council Environmental Services Department, East Lindsey District Council T: +44 (0)1507 601 111 F: +44 (0)1507 329 026 E-mail: -- Website: http://www.e-lindsey.gov.uk
Boston Borough Council Community Services, Environmental Health , Boston Borough Council T: +44 (0)1205 314200 F: +44 (0)1205 314247 E-mail: [email protected] Website: http://www.boston.gov.uk
South Holland District Council Environmental and Leisure Services, South Holland District Council South Holland T: +44 (0)1775 761161 F: +44 (0)1775 711 054 E-mail: [email protected] Website: http://www.sholland.gov.uk
NORFOLK
Borough Council of King’s Lynn and West Norfolk Leisure and Public Space, Street Cleansing, T: +44 (0)500 253 2687 F: +44 (0)1553 771657 E-mail: [email protected] Website: http://www.west-norfolk.gov.uk
North Norfolk District Council Contracts Division, Community Services Directorate, North Norfolk District Council T: +44 (0)1263 513811 F: +44 (0)1263 516212 E-mail: -- Website: http://www.northnorfolk.org
Great Yarmouth Borough Council Operational Services, Great Yarmouth Borough Council T: +44 (0)1493 857500 Phocine Distemper Virus Epizootic Investigation 2002/2003 8 F: +44 (0)1493 846 462 Website: http://www.great-yarmouth.gov.uk
SUFFOLK Waveney District Council Street Cleansing Department, Waveney District Council T: +44 (0)1502 523468 F: +44 (0)1502 523580 E-mail: -- Website: http://www.waveney.gov.uk
Suffolk Coastal District Council Environmental Services Department, Suffolk Coastal District Council T: +44 (0)1394 444306 F: +44 (0)1394 444354 E-mail: [email protected] Website: http://www.suffolkcoastal.gov.uk
ESSEX
Tendring District Council Conservation Department, Leisure Services T: +44 (0)1255 425501 F: +44 (0)1255 253200 E-mail:-- Website: http://www.tendringdc.gov.uk/
Colchester Borough Council Planning and Protection, Environmental Health, Colchester Borough Council T: +44 (0)1206 292590 F: +44 (0) 1206 282598 E-mail: [email protected] Website: http://www.colchester.gov.uk
Maldon District Council Environment Services, Maldon District Council T: +44 (0)1621 854 4 77 F: +44 (0)1621 852 575 E-mail: -- Website: http://www.maldon.gov.uk
Rochford District Council Housing, Health and Community Care, Rochford District Council T: +44 (0)1702 318 047 F: +44 (0)1702 545 737 E-mail: [email protected] Website: http://www.rochford.gov.uk
Southend-on-Sea Borough Council Emergency Planning Officer, Chief Executive and Town Clerks Department, Southend-on-Sea Borough Council T: +44 (0)1702 215 000 F: +44 (0)1702 215 110 E-mail: -- Website: http://www.southend.gov.uk
KENT
Medway Council Phocine Distemper Virus Epizootic Investigation 2002/2003 9 Front Line Task Force, Development and Environment Directorate, Medway Council T: +44 (0)1634 333 333 (Customer Services) F: +44 (0)1634 333 188 (Customer Services) E-mail: [email protected] Website: http://www.medway.gov.uk
Swale Borough Council Environmental Services, Swale Borough Council T: +44 (0)1795 417 850 F: +44 (0)1795 417 141 E-mail: [email protected] Website: http://www.swale.gov.uk
Canterbury City Council Street Scene Section, Environment and Street Scene Division, Community Services Department, Canterbury City Council T: +44 (0)1227 862 211 F: +44 (0)1227 785 705 E-mail: -- Website: http://www.canterbury.gov.uk
Thanet District Council Foreshore Department, Thanet District Council T: +44 (0)1843 577 000 F: +44 (0)1843 290 906 E-mail: -- Website: http://www.thanet.gov.uk
Dover District Council Environmental Health Department, Dover District Council T: +44 (0)1304 872 412 F: +44 (0)1304 872 086 E-mail: [email protected] Website: http://www.dover.gov.uk/ddc
Shepway District Council Environment and Street Scene, Shepway District Council T: +44 (0)1303 247 360 F: +44 (0)1303 247 396 E-mail: [email protected] Website: http://www.shepway.gov.uk
Phocine Distemper Virus Epizootic Investigation 2002/2003 10 Appendix 2.1
NEWS RELEASE
Department for Environment, Food and Rural Affairs Nobel House, 17 Smith Square, London, SW1P 3JR Out of hours: 020 7270 8960
Up to index
331/02 13 August 2002
GOVERNMENT FUNDS RESEARCH INTO DEADLY SEAL VIRUS NATIONAL HELPLINE SET UP TO COPE WITH HIGH VOLUME OF CALLS
A national helpline has been set up as part of a £250,000 Government funded project to find out more about a deadly seal virus which returned to the UK coast today.
The Department for Environment, Food and Rural Affairs, Scottish Executive and Welsh Assembly are funding the nine-month research project which is being led by the Institute of Zoology.
Its aim is to find out more about Phocine Distemper Virus (PDV) which killed about 18,000 common seals and about 400 grey seals when it last struck in 1988. At that time nobody knew what was causing the deaths - this was a new disease in seals.
Now the disease has again struck the UK coastline. Post mortem tests on some seals washed up on east coast beaches have tested positive for PDV. The disease has already struck the Dutch, Belgian, Norwegian and French coasts.
Animal Welfare Minister Elliot Morley said:
"This is a particularly nasty virus for which there is no known cure. Even if a vaccine had been tested and approved, the practicalities of injecting what are essentially wild animals, especially during the breeding season, could prove dangerous not only to humans but also to the very seals we would be trying to help.
"Some research has been done, but more is needed. This outbreak, as terrible as it is, does provide us with a chance to learn more about the virus and hopefully find a way of stopping it in the future. The new national helpline number should help the public and researchers by providing a simple way to get information where it can be best used as quickly as possible.
"The virus is not dangerous to humans, but it is important that the general public do not touch any seals washed ashore and contact the relevant rescue organisations as quickly as possible using the helpline. If the seals are alive they may bite, and it is always wise to stay away from animal carcuses. It is also important for people to keep their dogs away from any seals washed ashore as they could be susceptible to the virus."
The helpline will be the single contact point for the public to report seals washed up on beaches and will automatically direct callers to the appropriate organisation.
The RSPCA and the SSPCA are taking the lead on trying to help seals that are found washed up on beaches still alive. But the public has also been contacting them about dead seals - calls that need to be dealt with by the Institute of Zoology and local authorities. The new number should streamline the system and be more able to deal with the expected volume of calls.
No single body is responsible for the overall management of an outbreak of PDV in seals. But the Department
Page 1 for Environment Food and Rural Affairs has been working closely with a core group of bodies involved in the 1988 outbreak to co-ordinate preparation plans to deal with the virus and its impact on the seal community and coastal communities.
Mr Morley said:
"This is a naturally occurring disease affecting animals in the wild. But this does not mean that we can do nothing. We are working hard with top people in key fields of science and animal welfare, as well as our colleagues in the devolved administrations, tourism bodies and local authorities, to monitor and manage the situation from an animal health and welfare angle."
Notes for editors
If a member of the public finds a seal washed up on a beach they should call the helpline number 08712 447999.
The Institute of Zoology has been commissioned by DEFRA to:
z establish systematic survey and reporting of stranded seals nation-wide, referring reports of live animals to welfare organisations; z carry out post mortem and sampling of dead seals to establish levels of PDV infection; z estimate the current susceptibility of UK seals to the disease, and, with the assistance of the Sea Mammal Research Unit in St. Andrews, predict the impact of the outbreak as it develops; z monitor progress of the disease and produce information updates and forecasts of seal mortality to the Government and the public; and, z provide a source of scientific information to help with enquiries.
The new system will operate for England, Wales and Scotland. A similar system with a different number is being set up to deal with the situation in Northern Ireland. A response team has been set up to deal with reports of sick or dead seals and a network of volunteers to scan the County Down coast which is likely to be a badly affected area. Information will be shared between Northern Ireland, Wales, Scotland and England.
The core group of organisations involved in this co-ordinated project are:
The Royal Society for the Prevention of Cruelty to Animals The Scottish Society for the Prevention of Cruelty to Animals The Institute of Zoology Scottish Executive Environment Rural Affairs Department National Assembly of Wales Agriculture Department The Department for Environment Food and Rural Affairs The Department of Environment (Northern Ireland) The Sea Mammal Research Unit
In 1988, an outbreak of Phocine Distemper Virus (PDV) caused the death of 17-18000 common seals (Phoca vitulina) and 300-400 grey seals (Halichoerus grypus). The disease was first recorded in infected seals located around the island of Anholt (Denmark) and spread over several months to infect seals in the North Sea, Wadden Sea, Baltic and Irish Sea. Considerable scientific research was conducted to establish the cause of the outbreak and its impact on UK and European seals. Within the UK, the greatest declines in common seal populations occurred in the Wash and the Moray Firth.
Over the last couple of months, a virus virtually identical to the 1988 strain of PDV has again been associated with the deaths of common seals, starting in the same place, Anholt. If the spread of the disease follows the same pattern, it is expected to appear in the UK during August.
Further information on seals and PDV can be found at www.defra.gov.uk/wildlife- countryside/ewd/seals/index.htm
The RSPCA Press Office can be contacted on 0870 7540244. The Institute of Zoology can be contacted
Page 2 on 020 7449 6363.
Public Enquiries: 08459 335577
Press Notices available via DEFRA website
http://www.defra.gov.uk
END
Top of page
Page 3 If a Sick or dead seal is discovered by General Public, RSPCA or Land Owner please refer to the following decision tree.
IN THE INTERESTS OF HEALTH AND SAFETY NEVER APPROACH A SICK SEAL AND KEEP DOGS WELL AWAY
Hotline 08712447999
Is the seal alive?
Yes No
RSPCA/SSPCA Where is the seal?(Precise location, time date, condition and contact details)
England Scotland Wales Northern Ireland
Institute of MEM – Zoology Marine Environmental Monitoring SAC Inverness Quiole Countryside Centre
Data Collection
Post-mortem if appropriate
Yes NO Inform Local Authority and arrange for Data entered on UK central database disposal following the guidance note. (IoZ) (hyperlink to www.defra.gov.uk/wildlife- countryside/ewd/seals/disposal.pdf)
STATUS REPORTS
IF YOU FIND A SEAL WASHED ASHORE PLEASE RING THE DEDICATED REPORTING HELPLINE – 0871 2447999. IF YOU WOULD LIKE FURTHER INFORMATION ON THE PDV OUTBREAK IN YOUR AREA PLEASE CONTACT THE RELEVANT ORGANISATION BELOW. THESE ARE NOT GENERAL HELPLINES.
Institute of Zoology Institute of Zoology Regent`s Park London NW1 4RY tel: 020 7449 6672 fax: 020 7586 1457 email: [email protected]
SAC Inverness Wildlife Unit SAC Veterinary Science Division (Inverness) Drummondhill Stratherrick Road Inverness IV2 4JZ tel: 01463 243030 fax: 01463 711103 email: [email protected]
Marine Environmental Monitoring Marine Environmental Monitoring Penwalk Llechryd Cardigan SA43 2PS Tel: 01348 875000 Email: [email protected]
Quiole Countryside Centre Quiole Countryside Centre 5 Quay Road Downpatrick County Down BT30 7JB Tel: 028 4461 5520 Appendix 2.2
Wildlife and Countryside
Home | Contact Defra | About Defra | News | Access to information | Links | Search | Site A-Z
Homepage > Wildlife & Countryside > English & European Wildlife > Seals & Phocine Distemper Virus (PDV)
Seals and Phocine Distemper Virus (PDV)
PDV in seals was identified in 1988 when an outbreak (first detected near the island of Anholt in Denmark) proceeded to result in the death of over 18,000 common seals in Europe. It took about 4 months for the disease to travel from Denmark to the UK. In the UK, the disease was first reported from the Wash and then spread to the east coast of Scotland - in total about 1,500 seals were washed onto UK beaches. The population of common seals in the Wash declined by about half.
During June and July 2002 a virus virtually identical to the 1988 strain of PDV was again detected in the Kattegat and Dutch Waddensea areas. The current outbreak shows similarities to the last one: same original location, similar time of year (start of the breeding season) and a similar level of population density.
Since the 14th of August 2002 1794 seals have now been reported in the UK since the beginning of the PDV outbreak. These have mainly been located in the Norfolk/Wash area although cases of the disease have now been found in Yorkshire and Kent. The Institute of Zoology (Zoological Society of London) are currently carrying out Defra funded research into the virus, regular updates of this research can be found the Sea Mammal Research Unit Website: Sea Mammal Research Unit
These pages contain further information about the disease including what to do if you discover a sick or dead seal. Information may also be found on the co-ordination between Defra and other organisations in response to the current outbreak.
z Seals and Phocine Distemper Virus - information includes what to do if you spot an affected seal
z Do you own land along the coast? Letter providing guidance to private landowners along the coast
z Frequently asked questions about Phocine Distemper Virus (PDV)
z Phocine Distemper Virus in seals: suggested disposal options for seal carcasses (200 KB - updated 18/09/02) This guidance note lays out the options available to local authorities and private landowners of coastline where sick or dead seals have been discovered. It aims to give advice on the most appropriate methods of removal / disposal of such carcases and gives details of rendering and incineration facilities. It does not purport to give definitive advice to landowners on which disposal option they should adopt as local circumstances will need to be considered before final decisions are made.
z The options for a vaccination programme of Seals against Phocine Distemper Virus (PDV) in response to predicted PDV outbreak in UK in 2002 - This paper is a discussion note which explores the options to vaccinate seals against Phocine Distemper Virus (PDV) in the United Kingdom. It is a collaborative document and includes expert contributions from Animal Health, Defra, International Zoo Veterinary Group and RSPCA however it is not intended to be a scientific paper.
z Options for vaccination of seals in seal sanctuaries for protection against PDV - This paper is a discussion note which explores the options of vaccinating seals in sanctuaries against Phocine Distemper Virus (PDV) in the United Kingdom. It as a collaborative document and includes expert contributions from Animal Health, Defra, Sea Mammal Research Unit,
Page 6 Institute of Zoology, International Zoo Veterinary Group and RSPCA however it is not intended to be a scientific paper.
z Public health guidance note issued by the Scottish Centre for Infection and Environmental Health
z News release 331/02 of 13 August 2002
Other web links
Further more detailed information can be found at:
z Sea Mammal Research Unit - news page on the current outbreak and maps showing the distribution of seal populations in the UK.
z Common Wadden Sea Secretariat - for the wider European picture
z RSPCA page
If you require further general information please contact the Wildlife Management Branch (Defra) on 0117 372 8746
Page last modified: 27 November 2002
Page 7 Appendix 2.3
PHOCINE DISTEMPER VIRUS IN SEALS : SUGGESTED DISPOSAL OPTIONS FOR SEAL CARCASSES
Aim
This note provides guidance to private landowners and local authorities about the disposal of seal carcasses in England and Wales.
Background
1. Phocine distemper virus (“PDV”) was identified in 1988 when an outbreak (first detected near the island of Anholt in Denmark) proceeded to result in the death of over 18,000 common seals in Europe. It took about 4 months for the disease to travel from Denmark to the UK. In the UK, the disease was first reported from the Wash and then spread to the east coast of Scotland – in total about 1,500 seals were washed onto UK beaches. The population of common seals in the Wash declined by about half.
2. PDV has now been confirmed in Denmark, Sweden, Holland and Norway. On Tuesday 13 August the first case of PDV was confirmed in the UK. The current outbreak shows similarities to the last one: same original location, similar time of year (start of the breeding season) and a similar level of population density. On the available information, the possibility that this could result in mortality on a similar scale to 1988 cannot be ruled out.
3. This paper offers guidance to private landowners of beaches onto which seal carcasses are washed-up; and to local authorities in cases where there is no private landowner. (Subsequent references are to “the landowner”.) In each case the landowner will need to consider:-
• Health and Safety issues for personnel dealing with carcasses; • Disposal options including associated costs; and • Transport protocol for disposal.
4. The paper does not purport to give definitive advice to landowners on which disposal option they should adopt as local circumstances will need to be considered before final decisions are made.
Page 8 Health and Safety Issues
5 The disease is caused by a virus similar to distemper virus caught by dogs, but distinct from it. It is not dangerous to man but dogs (and possibly foxes) might be susceptible if they have not been inoculated against distemper. However, as with any animal carcass, dead seals may harbour zoonoses, so as a precaution the general public will be advised by the rescue organisations and DEFRA to keep away from any seals that are washed ashore and given details of who to contact. Landowners should support these initiatives as much as they are able.
6. Landowners are advised to remove any seal carcasses from the beach and dispose of them in an appropriate manner. Staff or contractors who have direct contact with the carcass are advised to wear the normal personal protective equipment appropriate for any cadaver disposal including face and eye protection to guard against splashes and gloves. Disposable coveralls or coveralls and footwear which can be cleaned and disinfected are equally effective. Records of staff and contractors carrying out disposal duties should be maintained, and appropriate health screening should be provided in consultation with the health authorities.
Disposal
7. Notification: Landowners will usually be alerted of a seal carcass in their area by either the Institute of Zoology, the RSPCA or local representative depending on whether the animal has been found dead or killed to end undue stress or suffering. The animal will be killed by the RSPCA according to the relevant welfare legislation and with due regard to the interests of the general public that may be present near the diseased seal (for example by erecting screens). Methods used for euthanasia will include lethal injection by pentobarbitone sodium @ 20% mainly for pups and some adults or a free bullet for adults. The RSPCA will remove all injected seals (Grade A environmentally contaminated waste) for incineration. The landowner should as soon as is practicable, dispose of seals which have been dispatched with a free bullet. Each local landowner should provide relevant contact details to the RSPCA and Institute of Zoology. It would be helpful if each landowner would supply the European Wildlife Division in DEFRA (telephone: 0117 372 8746) of the total number of carcasses that have been disposed on a weekly basis. The attached “decision tree” (Annex A) should help landowners understand the notification process. If landowners are notified directly by the general public of a seal washed ashore they should divert the call to the appropriate contact number as indicated in Annex A. Under no circumstances should they dispose of the carcass before notifying the RSPCA, the Institute of Zoology or regional representative.
8. Waste Disposal: A substance or object is waste within the terms of the Waste Framework Directive when its holder discards, intends to discard or is required to discard it. When a seal carcass is washed-up on a beach it
Page 9 becomes, under common law, the property of the landowner. The landowner is, therefore, “the holder” for the purposes of the Waste Framework Directive. (Similar considerations apply where a seal is killed on a beach to end undue stress or suffering – see paragraph 7.) This means that a seal carcass is classified as waste when the landowner discards it (ie disposes of it) or is required to discard it.
9. A landowner may be required to remove (ie to discard) a seal carcass where it is causing a nuisance either under common law or under the statutory nuisance provisions of sections 79 and 80 the Environmental Protection Act 1990 (“the 1990 Act”). Sections 79 and 80 of the 1990 Act require local authorities to serve a notice requiring a landowner to abate1 any nuisance caused by seal carcasses. The matters which may constitute a “statutory nuisance” for these purposes include:-
• Any accumulation or deposit which is prejudicial to health or a nuisance; • Any animal kept in such a place or manner as to be prejudicial to health or a nuisance; • Any other matter declared by any enactment to be a statutory nuisance.
10. The purpose of the Waste Framework Directive is to ensure that waste is managed2 and disposed of in ways which protect the environment and human health. In essence, this means the landowner’s ensuring that seal carcasses discarded as waste are consigned to someone who is either (a) properly authorised to collect and transport them (see paragraphs 19-24 below) or (b) properly authorised to dispose of them.
11. Disposal Options: Authorised incineration and approved rendering plants are the preferred options for the disposal of seal carcasses although licensed landfill sites may be considered under extenuating circumstances. Rendering should be undertaken in plants approved under article 7 of the Animal By- Products Order 19993 (“the 1999 Order”) to dispose of high-risk mammalian waste. If a significant number of carcasses needs to be disposed of then rendering may be the preferred option in view of the larger capacity these plants can offer. Annex B gives the relative advantages and disadvantages for each disposal option.
12. No additional costs are anticipated for clean down in renderers, as only routine cleaning will be required. This should, however, be confirmed with the individual renderers. However, staff that have handled seals should make sure that they change their clothing and thoroughly wash their hands before going home.
1 For example, by removing the carcasses and so discarding or disposing of them. 2 “Management” under the Waste Framework Directive includes the collection and transport of waste. 3 S.I. 1999 No. 646.
Page 10 13. There has been some concern about the capacity of authorised incinerators. Most large carcass incinerators are able to take animals up to 1.5 tonnes in weight and, as an average common seal weighs 130 kg, it is feasible to fit 10 seals into an incinerator at any one time. Costs of incineration vary with individual incinerators.
14. Annex C gives the locations and contact details of authorised incinerators and renderers who have indicated that they are willing to accept carcasses. The list also contains contact details for knackers. As a matter of urgency, landowners should consider what facilities are within a reasonable distance from the coastlines within their area. Many facilities are located in the west of the country (where most of the UK’s livestock reside) and, as seals are likely to be washed onto the east coast, transport costs (including the use of knackers) should be factored into the disposal plans.
15. Use Of Licensed Landfills: The protocol for accepting and disposing of carcasses at licensed landfill sites is much more complicated than for incineration or rendering. This option should only be used if approved rendering or authorised incineration capacity is not available. If landowners consider licensed landfill is the only option for the disposal of seal carcasses then they should liaise directly with the Environment Agency as soon as possible (Annex D, separate attachment – useful contact numbers).
16. Beach Disposal: There may be exceptional circumstances where the in- situ burial of carcasses may be considered. For example, where there is no vehicle access or where the beach is so remote that off-site disposal is impractical. However, this option should be adopted only after the Environment Agency has undertaken a risk assessment4 on an individual basis to assess the risks posed to the environment by the in-situ disposal of carcasses. Landowners should note that it is very unlikely that these risk assessments will conclude that beach burial is a permissible option in any but the most remote and inaccessible places.
17. However, if vehicle and human access is impossible then the only sensible course of action may be to leave the carcass to decompose. As the carcass will no longer be infectious a few hours after death then the carcass is unlikely to infect other seals and, given the isolated location, is unlikely to compromise public health.
18. Disposal Costs: The effect of Article 15 of the Waste Framework Directive is to require that the cost of disposing of waste must be borne by the holder. There are, therefore, no provisions for any compensation to be payable by Government or local authorities. Landowners will therefore need to bear the disposal costs and may wish to check whether this situation is covered by any personal insurance.
4 In consultation, as necessary, with the public health authorities.
Page 11 Transport
19. Where landowners themselves do not take seal carcasses to the preferred disposal options then they should consign them only to someone who is authorised to transport waste. Those who are authorised for this purpose include a person who is:-
• Approved to operate a rendering plant under article 7 of the 1999 Order; • Approved to operate a knackers’ yard under article 14 of the 1999 Order; or • Registered with the Environment Agency as a waste carrier.
20. Renderers And Knackers: Approved rendering plants are a preferred disposal option and many have their own transport facilities. Landowners may find it helpful, therefore, to contact a renderer in the first instance. Rendering plants which do not operate their own transport facilities may be able to contact a knackers’ yard which does. Depending on workload knackers are often able to pick up carcasses within one hour of notification. Carcasses will be taken either to the knackers’ yard and appropriately stored until collected by renderers as soon as possible or taken directly to an authorised incineration plant.
21. Knackers’ charges vary. For example, in Lincolnshire the charges are £70 per animal plus £10 per extra animal. Landowners should contact their local knackers’ yard for an indication of cost.
22. All vehicles and/or containers used by rendering plants and knackers’ yards to transport “animal by-products” should comply with article 6 of the 1999 Order. These requirements include the use of adequately covered leak- proof containers or vehicles. Vehicles must also undergo thorough cleaning and disinfection procedures. Disinfectants approved by DEFRA for use under General Orders under the Animal Health Act 1981 may be used for this purpose. A list of DEFRA approved disinfectants along with details of manufacturers names and addresses can be obtained from DEFRA, Animal Disease Control Division, Area 104, 1A Page Street, LONDON, SW1P 4PQ.
23. Registered Waste Carriers: The local office of the Environment Agency holds a list of registered waste carriers which may be inspected free of charge. However, inclusion on the Agency’s register is not a recommendation of an individual carrier’s suitability.
Page 12 24. Local Authorities: Local authorities and/or their waste collection contractors should be registered as waste carriers. Private landowners may wish, therefore, to consult their local authority to determine if the authority is willing to arrange collection and disposal of seal carcasses. The local authority may charge for this service.
Page 13 IN THE INTERESTS OF HEALTH AND SAFETY NEVER APPROACH A SICK SEAL AND KEEP DOGS WELL AWAY Annex A Hotline 08712447999
Is the seal alive?
Yes No
RSPCA/SSPCA Where is the seal? (Precise location, time date, condition and contact details)
England Scotland Wales Northern Ireland
Institute of MEM – Zoology Marine Environmental Monitoring SAC Inverness Quiole Countryside Centre
Data Collection
Post-mortem if appropriate
Yes NO
Data entered on UK central database (IoZ)
STATUS REPORTS Inform Local Authority and arrange for disposal following the guidance note.
Page 14 Annex B Disposal Option Advantages Disadvantages Approx. cost per tonne (TBC) Rendering 1. Suitable for all carcasses. 1. Time consuming and costly clean down procedure although this may £ 100 2. Able to provide own transport fleet not be necessary, as the disease is not communicable to humans. 3. Relatively large capacity 2. Poor geographical spread of plants across England and Wales, though 4. Less public opposition than most other disposal there is one rendering plant in Lincolnshire, close to the Wash. options 3.
Commercial 1. Short and inexpensive clean down procedure 1. Very limited capacity although likely to be sufficient for the number £125 Incineration (approx 2 hours). of predicted seal carcasses. 2. Able to deal with carcasses at very short notice 3. This is a total destruction method
Licensed landfill 1. Sites already engineered and licensed to receive 1. Possible contravention of legislation shortly due to come in force (EU £ TBA waste Animal By-products Regulation) 2. Many potential sites across country, wide 2. Possible reluctance of some site owners to assist although at least coverage three waste management companies, with at least eight sites have 3. Subject to terms of direction, any indicated they are willing to help. environmental liability arising from the 3. Possibility of challenge under the Human Rights Act from local disposal falls to landfill operators residents 4. Opposition from local public, authorities, MPs, pressure groups 5. Sites would have to meet EA criteria for carcass disposal – may eliminate some potential sites 6. Possible restriction on capacity (EA stipulated during FMD 2001 that only 5% of all waste can be animal carcasses).
Page 15 Figure 1:Map of renderers and incinerators in the UK
Page 16 Annex C
List of Animal Carcass Incineration Plants Co.Name Address Telephone/Fax ENGLAND Harry Atkinson Mayfield House, Malton Road, Pickering, Tel: 01751 472885 North Yorkshire, YO18 8EA Fax: 01751 471599 Cremtor Greycote Lane, Forches Cross, Tel: 01626 353990 Newton Abbott, TQ12 6PQ Fax: 01626 353990 The Cambridge Pet Crematorium. A505 Main Road, Thriplow Heath, Tel: 01763 208863 Nr. Royston, Herts, SG8 7RR. Fax: 01763 208885 Goodman’s Incineration Warwick Road, Ettington, Tel: 01789 740240 Stratford-on-Avon, CV37 7PN Fax: 01789 740868 Harry Hawkins & Partners Chates Farm, Cowfold, Horesham, Tel: 01403 864361 West Sussex, RH13 8DU Fax: 01403 812954 Ottery Abattoir Ltd Raxhayes Farm, Ottery St. Mary, Tel: 01404 812954 Honiton, Devon, EX11 1PQ Fax: 01404 812954 Incineration South West Ltd. Stoneybridge, Pengover Road, Tel: 01579 343243 Liskeard, Cornwall, PL14 3NH. Fax: 01579 344520 A. Lawton Birch House, Birch Vale, High Peak, Tel: 01663 744154 Derbyshire, SK22 1DH Fax: 01663 741553 Wessex Incineration Roewood, West Woodlands, Tel: 01373 465707 Nr. Frome, Somerset, BA11 5EN. Fax: 01373 451114 Tellams Incineration Valley View, Woodlands, Tel: 01647 24472 Cheriton Bishop, Exeter,Devon, EX6 6HH. Fax: 01647 24678
Page 17 Co.Name Address Telephone/Fax F Redfern & Sons Ltd 9 Green Lane, Buxton, Tel: 01298 24114 Derbyshire, SK17 9DP Fax: 01298 24511 John Warren (ABP) Ltd Eden Hall, Hamsterley, Bishop Auckland, Durham, DL13 3QG Tel: 01388 488215 Fax: 01388 488599 Peaceful Pets Ltd The Grange, West Rudham, Kings Lynn, Norfolk. PE31 8SY Tel: 01485 528 141 Fax: 01485 528 444 WALES Animal Waste Services Ltd Tyddyn Daniel, Marchwiel, Tel: 01978 661871 Wrexham, Clwyd. LL13 0TS. Fax: 01978 661756 Tom Goddard & Sons, Camrose Incineration Causeway Factory, Camrose, Haverfordwest, Pembrokeshire, Dyfed, SA62 Tel: 01437 710339 6HG. Fax: 01437 710839
Page 18 Knacker Yards – UK
Company Address1 Address2 City County Post Code WorkPhone David Abbott Dewey Lane Farm Brackenfield Alfreton Derbyshire DE55 6DB 01629 534271 01629 534412 Harry Atkinson Lillac House Thorpe Bassett Malton North Yorkshire YO17 8LU 01944 758316
J.R.H. Baxter & 6 Bell Lane Moulton Spalding Lincs PE12 6PQ 01485 601275 Son
R. Bennetts & Fal Valley Tannery Grampound Truro Cornwall TR2 4RX 01726 882417 Sons (Grampound) A & D. Biles Somerton Farm Cowes Isle of Wight PO31 8PT 01983 522351
Boon Bros The Mill House Allscott Telford Shropshire TF6 5EE 01743 821215 01743 821322 (Fax) Brassington & Easing Moor Farm Thorncliffe Leek Staffs ST13 7LW 01538 300243 Co
Brewers Redmoor Callington Cornwall
F M Caine & Seifton Villa Culmington Ludlow Shropshire SY8 2DF 01584 861206 Sons Ltd 01584 861687 (Fax)
Chetwynd Llwyncelyn Mydroilyn Lampeter Dyfed SA48 7RP 01545 580532 Animal Products Ltd J P Clarke The Knacker Yard, Valley Melton Woodbridge Suffolk IP12 1LL 01394 382592 (Clarkes of Farm Road Melton) E. Clutton & Tyddyn Daniel Marchwiel Wrexham Clwyd 01978 661871 Sons 01978 661756 (Marchwiel) Ltd T C & B J Tolney Lane Newark Notts NG24 1LE 01636 704601 Crowden
Page 19 Company Address1 Address2 City County Post Code WorkPhone Charles Bishops Lane Ringmer Sussex BN8 5JT 01273 812313 Diplock 01273 814478 (Fax) Jim Douglas & The Factory Yard Cwmann Lampeter Dyfed SA48 8ES 01570 422310 Sons
George Eaton Howarth Cross Mill Smallbridge Rochdale Lancs 01706 45950 Ltd
Frome Vale Greenwood Acres Chantmarle Dorchester Dorset DT2 0HD 01935 83264 Animal Products Green Bros Willow Grove Murton York YO3 9XE 01904 489329 01904 489505 (FAX) Tom Goddard Causeway Factory Camrose, Pembrokeshire Dyfed SA62 6HG 01437 710339 & Sons Haverfordwest 01437 710524 (E) D.& J. Goff. Hook Mills Chardston Nr. Axminster Devon
H.R. Hawkins Chates Farm Cowfold Horsham Sussex 01403 864927
J. Hodson & Lodge Road Donnington Telford Shropshire 01952 613915 Son
A Holt The Knackers yard Marsh Lane Stanstead Abbotts Herts SG12 8HH 01920 870002 A. Hughes Jerusalem Farm Skellingthorpe Lincs 01522 682626 (Skellingthorpe ) Ltd Peake Bros. Stoneybridge Pengover Road Liskeard Cornwall PL14 3NH 01579 342212 01579 344520 (Fax) W H James & Astwood Bank Redditch Worcs B96 6DL 01527 892458 Son
A. Lawton Birch House Birch Vale Stockport Cheshire SK12 5DH 01663 744154 01663 741553 G.W. Lord Westwinds Walkerith Road Morton Gainsborough, DN21 3DE 01427 3321
J.W. Martland Bartons Farm Moss Lane, Nr. Ormskirk Lancs L40 4AU 01704 893161
Page 20 Company Address1 Address2 City County Post Code WorkPhone & Sons Burscough
Maslins Greenfield Mardenhill Crowborough East Sussex TN6 1XL 01892 661282 01293 882812 William Martin Rowlands, Bakers Lane Black Notley Braintree Essex CM77 8QS 01376 331136 & Son
Mitchell By- Hurstfield Farm, Black Thornton Bradford West Yorkshire BD13 3RR 01274 833084 Products Ltd Dyke Kane T. Newman Ltd Portfields Buckingham Bucks MK18 1EW 01280 813344 01280 813344 (Fax) J.E. Noddings Stable House Charltons Saltburn-on-Sea Cleveland 01287 610181 & Son 01287 630530 (Fax)
A. Parker Power Station Road Rugeley Staffs WS15 2HS 01889 582167 01889 583830 (Fax) Passey & Son 5 Sherrard Mead Church Road Shaw, Newbury Berks
H. Pawson & Station Road Donington-on- Louth Lincs 01507 343237 Son Bain
D.H. Payne & Bridge House Semington Trowbridge Wilts BA14 6LN 01225 703281 Sons
T.H. Robinson Over Raygill Farm Ingleton Via Carnforth Lancs 01524 261144 & Son
SB & Co. Unit 12 Charlesfield St. Boswells Melrose TD6 0HH Industrial Estate F D Statton & Green Trees Davidstow Camelford Cornwall PL32 9XU Son
John Warman The Paddocks Shotesham Norwich Norfolk NR15 1YT 01508 550238
John Warren Eden Hall Hamsterley Bishop Auckland Co. Durham DL13 3QG 01388 488215/488225 Animal By- 01388 488599 (Fax)
Page 21 Company Address1 Address2 City County Post Code WorkPhone Products Ltd B. Webster & Eastrington Goole North DN14 7XL 01430 440336 Sons Humberside (Eastrington) Ltd
Page 22 Renderers approved to process High-risk Mammalian material (Updated 08/08/2002)
Renderer Type of Material Address Postcode Phone Processed No.
Fats & Proteins UK Ltd SRM, Nightingale Hall LA1 3JT (01524) High/Low-risk ABPs Quernmore Road 64251 Lancaster
Forrest (W) & Son SRM Omoa Works ML1 5LY (01698) Biggar Road 860149 Newarthill Motherwell Hughes (A) & Son (Skellingthorpe) Ltd High/Low-risk Jerusalem Farm LN6 4RL (01522) Skellingthorpe 682626 Lincoln
Omega Proteins Ltd High-risk Mammalian & Erling Works BD13 3SQ (01422) Poultry Half Acre Road 362734 Thornton Bradford Pears (J G) (Newark) Ltd Low-risk/High-risk Poultry The Bonemeal Factory NG23 6FL (01226) & SRM Low Marnham 762175 Newark Nottinghamshire Peninsular Proteins Ltd SRM School Lane EX38 7AJ (01805) Torrington 623656 North Devon
Pointon Processing SRM Felthouse Lane ST13 7BT (01782) Cheddleton 550115 Leek Staffordshire Waddington SRM The Refinery BD3 9LP (01274) 54 Buck Street 734271 Bradford
Page 23 Appendix 2.4
Department for Environment, Food and Rural Affairs Seals and Phocine Distemper Virus (PDV): Do you own land along the coast? Letter providing guidance to private landowners along the coast
I am writing to alert you to the possible spread of Phocine Distemper Virus (PDV) in seals that reside in UK waters and the possible knock on effects this may have for you, as a coastal landowner.
Background
PDV was identified in 1988 when an outbreak (first identified near the island of Anholt in Denmark) proceeded to result in the death of over 18,000 common seals in Europe. It took about 4 months for the disease to travel from Denmark to the UK. In the UK, the disease was first reported from the Wash and then spread to the east coast of Scotland - in total about 1,500 seals were washed onto UK beaches. The population of common seals in the Wash declined by about half.
PDV has now been confirmed in Denmark, Sweden, possibly Norway and Holland and, on Tuesday 13 August, was confirmed in 5 seals washed onto a beach in Norfolk.
The current outbreak shows similarities to the last one: same original location, similar time of year (start of the breeding season) and a similar level of population density. On the available information, the possibility that this could result in mortality on a similar scale to 1988 cannot be ruled out.
Who is liable?
If a seal carcass is washed up on land that you own and is considered by the local authority to be a statutory nuisance then you, as a private landowner and the 'occupier' of that land, will be liable for arranging for its disposal and for paying the associated costs (whether you make the necessary disposal arrangements yourself or ask your local authority to do so for you - see the paragraph below on disposal of carcasses). Local authorities are NOT liable to meet the costs of 'nuisance' such as this on land that is owned by a private individual or organisation; they are only liable for (and are regarded as 'occupiers' of) land within their boundary that is not in private ownership. Under the relevant legislation - the Environmental Protection Act 1990 - it is clear that occupiers (whether private landowners or local authorities) are liable for 'nuisance' on their property, even if it was caused by others or is due to natural causes. The relevant sections of the Environmental Protection Act 1990 are Sections 79, 80 and 82.
How will you know a carcass has been washed onto your land?
Page 24 You will probably be alerted that a seal has been washed onto your land from your local authority. Most seal sightings will either be reported by the general public using the reporting "hotline" number (08712 447999) which diverts callers to the relevant rescue or reporting organizations such as the Institute of Zoology or the RSPCA. The Institute of Zoology has been contracted by DEFRA to monitor the progress of the outbreak particularly in recording numbers of dead seals. They will co-ordinate with local authorities in England and also collate information from reporting organisations in Scotland, Wales and Northern Ireland to provide a UK wide information source. The RSPCA will monitor numbers of live sick seals, rescue and treat sick seals in treatment centers, euthanase seals when necessary and co-ordinate with local authorities. The Institute of zoology and RSPCA will work closely together.
The four reporting organisations for dead seals in the UK depending on whether seals are found in England, Scotland, Northern Ireland and Wales will routinely report their findings to the relevant Local Authority. The Local Authority will hold a list of landowners, including your contact details, so they can alert you as soon as possible. Clearly, if you or your representatives find a seal then it is important that you use the national reporting number immediately.
Disposal of carcasses
It is important that seal carcasses are removed from a beach and disposed in an appropriate way to ensure there is no risk to the environment or public health. A guidance note sets out health and safety issues, transport considerations and the preferred disposal routes along with a number of useful contacts.
It is important that you read this guidance and formulate your own disposal plan for seal carcasses. If you decide that you do not want responsibility for disposal then you should contact your local authority who will be able to help - this will probably be a chargeable service.
Further Information
Finally, you will find further information about the PDV outbreak on the following websites:
Sea Mammal Research Unit - news page on the current outbreak http://smub.st-and.ac.uk/pdvgen.htm
Common Wadden Sea Secretariat - for the wider European picture http://cwss.www.de/news/news/Seals/01-seal-news.html
RSPCA page (for children) - http://www.rspca.org.uk/
If you require further information please do not hesitate to contact me.
Tanya Arkle DEFRA Wildlife Management Branch Zone 1/14d
Page 25 Appendix 2.5
Wildlife and Countryside
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Homepage > Wildlife & Countryside > English & European Wildlife > Seals & PDV > Frequently asked questions about PDV
Frequently asked questions about Phocine Distemper Virus (PDV)
Nature of the virus and its effects Risk of infection to humans and animals Action being taken Vaccination and Exclusion Communications
The Nature of the Disease and its Effects
What types of seals the virus is affecting?
COMMON SEAL: Phoca vitulina Males grow up to 185cm, 130kg: females are generally smaller GREY SEAL: Halichoerus grypus Males grow up to 230cm, 310kg: females are generally considerably smaller
How many seals are there?
Both common seals and grey seals are found around the UK coast. There are currently over 3,000 common seals in the area of the Wash, with small groups further up the east coast and a few along the south coast of England. There are large populations around Scotland.
What causes the disease?
The disease is caused by a virus similar to distemper virus caught by dogs, but distinct from it. It is called the Phocine Distemper Virus (PDV) because it was first found in phocid seals. The virus incubation period is 10 to 14 days. The virus is infectious.
What are the symptoms?
Symptoms - None of the symptoms listed are specific or diagnostic for this virus. Symptoms include respiratory problems - coughing, nasal discharge, discharge from the eyes. Also, a reluctance to move, subcutaneous emphysema (air bubbles under the skin) of the head and neck and occasional problems of the nervous system causing disorientation. Possible vomiting/diarrhoea. Animals become unable to dive to feed themselves. The disease is confirmed by blood testing diseased animals or tissue sampling dead animals (which is why the diagnosis of the UK outbreak took a while). PDV affects the immune system of the seal, leaving it susceptible to other infections such as pneumonia.
How does the disease spread?
The disease spreads as infected animals moved around. It spreads between animals in close contact in the same way a cold spreads in humans - by inhalation of the virus or through contact with secretions such as mucus, or faeces. In 1988 the disease spread from Scandinavia. It took 2-3 months to reach the UK from the original outbreak in the eastern coastal areas of Denmark. It first spread to the Waddensea around Germany and the Netherlands and from there it reached the UK, first appearing around July and leading to high mortalities in August in the Wash.
How many seals died in 1988?
Page 26 Common seals are far more susceptible to the disease - over 50% of common seals may die whereas around 10% of grey seals. Around Europe over 18,000 seals died. Around the UK reported counts were:
Scotland: about 1,300 Irish Sea: about 330 South west England: around 50 North east England: around 60 South east England (Suffolk, Kent, Sussex): about 24 East Anglia (The Wash): around 1,300 Estimates were higher, with over 1,500 disappearing from the Wash alone.
What proportion of seals wash up on the shore dead?
In areas such as the Wash where seals haul out on sandbanks away from shore, sick animals will not appear on the beaches immediately. Most animals that wash in to the beaches will be dead already. The sick animals will remain out on the sandbanks and possibly be in extremely poor condition when they turn up on beaches.
Have there been any cases reported in British waters during this recent outbreak?
Tissue samples taken from dead seals at the end of July by the RSPCA, returned positive on 13th August 2002, confirming our fear that the highly infectious virus is now spreading through the common seal population in the UK.
What effect will the virus have on our seal population, especially as it is the breeding season?
In 1988 up to 60% of seals were killed by PDV around Denmark, Sweden and the Netherlands. The major population of common seals in the Wash was hit very hard, about 50% or around 1,500 animals died in this area alone. The scale of deaths in Denmark and Sweden - the estimate on 11 July is over 1,400 animals dead [updates of these numbers obtainable from Wildlife Department: 0870 7540 205, or from website www.waddensea-secretariat.org] - suggests that immunity to the disease is low. The seals in the UK may also be susceptible. The virus kills adults and pups, and it causes pregnant females to lose their pups. The recovery rate of infected adults can be as low as 20%. England could once again lose up to half of its common seal population. The Wash population was slower to recover than other populations in Europe though after 14 years it is back up to its pre-PDV 1988 level. There have been small pockets of the disease in common seal groups since 1988. This may mean that some residual resistance exists and animals may not be as susceptible as in 1988.
What about grey seals?
Grey seals were far less susceptible to the disease in the last outbreak. Pregnant females lost their pups and over 100 adults died, but this was nothing like the scale of the common seal deaths. It would be impossible to vaccinate the grey seal population.
Is this the first time the virus has threatened the UK seal population since the 1988 outbreak?
This is the first time the disease has reappeared on this scale since the 1988 outbreak, however it has been present in small pockets in the European seal population.
Does it threaten seals anywhere else in the world?
It has been suggested that this disease poses a threat to the endangered Monk Seal. A remaining population on the Mauritanian coast of Africa suffered high mortalities a few years ago and PDV was suggested as one of the causes. However it was not confirmed that PDV caused the mortalities. The virus also affected the Lake Baikal Seal, a seal unique to this lake in Russia, in 1988. A similar disease has been found in dead porpoises from the North Sea.
Is this the worst virus to affect seals (in the UK/worldwide)?
Page 27 Yes, as far as we know.
What is the worst case/best case scenario when the virus hits?
The disease may kill as many seals as last time - there could be 1500 dead seals in the Wash alone. The animals that survived in 1988 and bred may have passed on some immunity to later generations however deaths in Scandinavia suggest that the population has not maintained much immunity. However seals closer to the UK, e.g. in Belgium, have been more recently exposed to the virus so there may be sufficient immunity in local North Sea animals to limit the spread of the disease.
They are wild animals, shouldn't we let nature take its course?
If we let nature take its course it would ensure that the animals that survived were naturally the strongest. However, large numbers of seals will be washed up alive and we should act in the interests of their welfare. This could mean either putting them to sleep, or rehabilitating them.
Does the spread/introduction of the virus have anything to do with man?
Impossible to say. There is no evidence that the disease came from canine distemper virus. However there is circumstantial evidence that links the spread of the disease with pollution.
Is pollution to blame?
There was some scientific research done after the last outbreak that suggested that there might have been higher mortality rates in areas where seals were more contaminated with pollutants but a full-scale comprehensive study was not carried out and results were inconclusive.
Risk of Infection to Humans and Animals
How does the virus spread?
It spreads between seals mainly through coughing whereby other seals inhale the virus. Dung, mucus and food waste can also harbour residues of the virus.
Is the virus dangerous to humans?
The virus itself does not present a danger to public health. However, pathogens such as bacterial infections can develop in the carcasses of the seals as in other animals, which present a risk to health. It is therefore advisable not to touch dead seals.
Can I still go to the beach?
There is no reason to avoid the beach as long as you steer clear of any dead or dying animals on the beach. If the animal is still alive, do not approach it as it could bite or carry pathogens (other than the virus) which could be harmful to your health. You should never touch a dead animal - ring the helpline 08712 447999.
What do I do if I've touched a sick or dying seal?
The virus itself is not dangerous to people, but the seal could be harbouring other bacterial or viral infections which are transmittable to people. If you do contract certain symptoms, it is important to tell your doctor you have been in contact with a sick or dying seal.
How sick can an infected person get? Do drugs exist to treat the disease in humans?
The virus itself does not transmit to humans. But a seal might be carrying other bacterial or viral pathogens, which could make you sick. How sick someone becomes will depend upon the nature of the infection, sometimes drugs will be prescribed to combat an infection.
Is the virus dangerous to animals?
Page 28
The virus may infect dogs. Pet owners need to be aware of this. Dogs inoculated against canine diseases are not at risk.
Do dogs die of the virus?
The virus may be fatal to infected dogs, which have not been inoculated. As with the seals, some dogs will survive the virus, but they may suffer brain damage.
Is there a risk of an epidemic among fish or birds?
No, the virus is not transmitted to fish or birds.
Are fishermen or people walking on the mud flats at risk?
The virus does not present a risk to public health. However, like everyone else, fishermen and walkers should stay away from dead or sick seals because they may harbour other pathogens.
Is a dead seal a greater threat to health than a sick seal?
It makes no difference. In any case, do not touch, but call the helpline - 08712 447999. Bear in mind that a live seal can inflict quite a serious wound on a human.
Action being taken
What is Defra doing?
Drawing on the lessons that have been learned during the last outbreak, DEFRA is helping voluntary organisations prepare and cope with the PDV outbreak as it hits UK waters. Discussions have been held about the disposal and vaccinations options for seal carcasses and a resulting guidance note can be seen on the website.
Defra have commissioned the Institute of Zoology (Zoological Society of London) to monitor, report and produce information about the progress of the virus. The helpline is funded by DEFRA and the devolved administrations (NAWAD, SEERAD and DoE NI)
We are working closely with voluntary organisations and other government departments these include; The Royal Society for the Prevention of Cruelty to Animals (RSPCA), The Scottish Society for the Prevention of Cruelty to Animals (SSPCA), The Institute of Zoology (IOZ), Scottish Executive Environment Rural Affairs Department (SEERAD), National Assembly of Wales Agriculture Department (NAWAD), The Department of Environment (Northern Ireland) (DoE NI), The Sea Mammal Research Unit (SMRU).
What is the Institute of Zoology doing?
As part of a £250,000 project The Institute of Zoology (IoZ) have been commissioned to:
z Establish systematic survey and reporting of stranded seals nation-wide, referring reports of live animals to the welfare organisations z Carry out post-mortem and sampling of dead seals to establish levels of PDV infection z Estimate the current susceptibility of UK seals to the disease, and, with the assistance of SMRU, predict the impact of the outbreak as it develops z Monitor progress of the disease and produce information updates and forecasts of seal mortality to Government and the public z Provide a source of scientific information to assist with media enquiries. Work has now started. Volunteers are rapidly being recruited for the systematic surveying of seals around the UK and it is hoped that the systematic surveying will begin next week.
What is the RSPCA doing?
The RSPCA Norfolk Wildlife Hospital, which is the focal point for treatment of affected seals, is still waiting for results of samples taken from a further 20 sick seal pups currently in care in its
Page 29 isolation unit. The Society has already scaled down normal operations and prioritised manpower to the affected areas on the English coastline to deal with the high number of seals that could be seriously taken ill or die as a result of the virus. Over the last few weeks, the hospital has seen a higher than average mortality rate among pups. The RSPCA Norfolk Wildlife Hospital is currently the only facility in the country taking in sick, potentially infected seals, which RSPCA staff are collecting from beaches. The RSPCA is also collaborating closely with the voluntary group, British Divers Marine Life Rescue, to survey the seals in the Wash for widespread signs of sick or suffering animals.
Can sick seals be brought in for treatment?
It is very difficult to catch healthy seals, so animals that are readily captured are usually already very ill. Some of these animals will already be close to death and beyond treatment, so immediate euthanasia is recommended. Less severely affected animals may be suitable for transport to rehabilitation facilities.
What is the survival rate of seals brought in for treatment?
In 1988 the RSPCA Seal Assessment Unit was established at Docking in Norfolk to cope with the outbreak of PDV. 88 animals were brought in to this facility. 65 died and 23 were eventually released. 74% of animals brought in for treatment died.
Does the RSPCA have facilities for treating seals?
The RSPCA Wildlife Hospital in Norfolk has specialist seal treatment facilities, and was established specifically in response to the 1988 outbreak when no facility of the type existed.
Vaccination and Exclusion
Can healthy seals be vaccinated?
There is a vaccine against PDV but this cannot be administered easily to the currently healthy population - the animals are very difficult to catch. They are also breeding. Any attempt to pursue/catch animals will cause adults to flee from the breeding beaches. There is a high risk that this will lead to pup abandonment. Seals currently in rehabilitation facilities, such as orphaned pups, can be vaccinated against PDV if the vaccine is available. Although it is proving very difficult to get hold of any PDV vaccine. Details of the vaccination options are available in a guidance note, which conclude that this course of action is not appropriate at this stage.
What should I do if I find a dead or live seal? Who do I phone?
It is important that people report any dead or alive seals, which have been washed ashore immediately. They should phone the dedicated helpline on 0871 2447999 and it is crucial they have the following details:
z Precise location of the animal z Time and date z Symptoms they observed
They should never approach a sick seal and should keep dogs well away - they could contract the disease
Are there any other damage limitation techniques?
None. It is unacceptable to reduce the number of seals. Even such a cull would not prevent the disease spreading as common seals group together at this time of year to pup and moult. Even when the population density is low seals regularly come into contact with one another, even over considerable distances.
What happens to the washed up seals?
Page 30 Once a sick or dead seal has been reported then experts will take a decision about the most appropriate course of action, sick seals may be removed to a rescue centre for treatment and carcasses will be disposed of in the most appropriate way. A guidance note explaining the disposal options for seal carcasses can be found on the DEFRA website.
Can the seals be moved to another location?
This is not feasible. There is no guarantee that we would be moving healthy seals - they could already be incubating the disease so we could actually be contributing to the spread. Seals move very widely naturally. The disease will inevitably reach seals if they are susceptible.
Can I take a seal home and look after it?
No, it would be an offence and in any case would be very unwise. Only expert rescue centres can provide seals with the proper care and attention that is needed.
Can I help, perhaps by taking care of sick seals?
Rescue centres do sometimes need help from volunteers. Further information can be found on the RSPCA website
Can I donate money to support seal rescue efforts?
The RSPCA is a charity and welcomes all donations. Further information can be found on the RSPCA website
Communications
How are the public and visitors to the area informed?
A press release has been issued by Defra. Information concerning the disease can be found on the following websites: RSPCA - http://www.rspca.org.uk/ The Dutch website - http://www.minlnv.nl/ - under zeehondenziekte Institute of Zoology - http://www.ioz.ac.uk/ Sea Mammal Research Unit - http://www.smub.st-and.ac.uk/
Page last modified: 9 October 2002
Page 31 Appendix 2.6
Wildlife and Countryside
Home | Contact Defra | About Defra | News | Access to information | Links | Search | Site A-Z
Homepage > Wildlife & Countryside > English & European Wildlife > Seals & PDV > The options for a vaccination programme of Seals against PDV
The options for a vaccination programme of Seals against Phocine Distemper Virus (PDV) in response to predicted PDV outbreak in UK in 2002
This paper is a discussion note which explores the options to vaccinate seals against Phocine Distemper Virus (PDV) in the United Kingdom. It is a collaborative document and includes expert contributions from Animal Health, Defra, International Zoo Veterinary Group and RSPCA however it is not intended to be a scientific paper. For further technical information please contact Ian Robinson, RSPCA and Andrew Greenwood, International Zoo Veterinary Group.
It is also available here as an Adobe Acrobat pdf file (19 KB)
Summary
z A vaccination programme is considered to be a risk to both humans and seals. z Effective immunisation of the seal population in the wild is unlikely to be feasible. z An experimental vaccine exists in Holland but will not be available in the UK because it has not been tested to EU standards and there are insufficient supplies. z Vaccination of seals in sanctuaries is a reasonable possibility but seals may have to remain isolated for a lengthy period of time if the vaccine used has not been tested z If a tested vaccine was available and safe there is a possibility of vaccinating seals in sanctuaries.
Background
The last outbreak of PDV in 1988 killed over 18,000 seals in Europe. In the UK which has both common and grey seals around its coast, the populations in the Wash and Moray Firth were most effected. Common seal populations are more susceptible to the disease but have largely recovered since 1988. Those surviving exposure in 1988 will have acquired resistance to the disease. However, tests suggest that less than 10% of the population in the UK is likely to be resistant and there is potential for high mortality if an outbreak reaches the UK, particularly in the Wash. Vaccination is a possible option to reduce the number of seals affected by the virus and perhaps contain the outbreak. This paper discusses the possible options for vaccination of seals.
Knowledge of the disease
PDV is a virus similar to Canine Distemper in dogs. The virus is passed between individuals by close contact and the symptoms include respiratory problems. Death is often caused by secondary infections such as pneumonia as PDV affects the immune system. In dogs, where the dam has been exposed to natural infection or has been vaccinated, a temporary natural immunity (maternal antibody) is passed from dams to pups which may last for many weeks. Pups are either vaccinated at 8-10 weeks of age and again at 10 to 12 weeks or given a single dose of vaccine at 10 to 12 weeks of age. The booster interval for UK authorised canine distemper can be up to 2 years. Provided the immune mechanisms are the same in seals, there is transfer of maternal antibody and this passive immunity lasts for a similar period as in dogs, Veterinary Exotic Disease Division suggests that seal pups could be vaccinated to produce some protection to the individual. Whether booster vaccination would be needed would depend on the prevalence of natural infection in the population. Vaccination strategies are usually aimed at protecting populations rather than individuals. If it were required to protect an entire population then, as a rule of thumb a minimum of 60% and ideally 90% of the population would need to be vaccinated. Administering the vaccine would be possible in pups as they are easier to handle on shore than adults. If only 10% of the population of seals were exposed to PDV in the last outbreak the vast
Page 32 majority of pups born since then will not have acquired immunity and there would not be any maternal antibody to effect the vaccination. The pups are likely to respond to a vaccine at an early age but it is not clear what age the pup would need to be vaccinated. The Veterinary Exotic Disease Division is cautious of the unknown impact of administering a man-made vaccine into a wild animal population. It would need careful consideration on ethical grounds.
Practicalities of administering a vaccine
Seals are large, wild animals that spend a substantial proportion of their time at sea and haul out in remote areas to moult and pup. To attempt to catch these animals at sea would be highly dangerous and involves risking physical injury and stress to the seal. The stress of being caught may depress the seal’s immune system and make them more susceptible to infection generally. In theory seals could be caught when they are on land. It would be particularly expensive to reach these remote areas and ensure Health and Safety guidelines are followed. The ‘hauled out’ females will be particularly vulnerable to physical injury whilst giving birth and feeding young pups. The young pups would be easier to catch and handle but it is not known how the stress would affect them and how their immune systems would react to a vaccine. It is also worth noting that the environment in the Wash is not suited to catching seal pups as the sand banks only appear at low tide and common seals pups swim from birth. The RSPCA would only support attempts to pursue/catch seals on shore, if it can be guaranteed that the seals are not injured. In addition adults may flee from the breeding grounds and cause injuries to seal pups and possibly lead to their abandonment. The International Zoo Vet Group believes that vaccination of seals would cause minimal stress, especially if carried out by remote injection and the benefits of vaccination would outweigh the possible impacts of developing PDV. However, the International Zoo Vet Group regards remote injection as impractical with current technology. The RSPCA would support investigation into administering a vaccine orally (as used in wild foxes) by feeding fish or using misting spraying. However, the success of these methods is unreliable as seals do not tend to eat dead fish and the accuracy of the spraying will be variable according to weather conditions. Veterinary Exotic Disease Division have also made the point that it is not known whether existing vaccines would be effective if administered by these route.
Design of a vaccination programme - Epizootiological considerations
A vaccination programme should consider the effect of immunization on the population as a whole. The main aim of a vaccination programme should be to establish a level of immunity where the proportion of immune seals is sufficiently high to reduce the transmission of the infection to susceptible seals. The level of immunity required in seals is unknown. To ensure a suitable level is attained following basic principles the Veterinary Directorate of Defra recommends that a high proportion are immunised (60-90%). In Britain the number of common seals has been estimated at a minimum of 36,345 (NERC Special Committee on Seals) from surveys carried out between 1996 and 2000. Approximately 32,000 are found in Scotland and 4,270 in England, of which 2,785 are found in the Wash. To immunise a high proportion, 90% (32,000) of the seal population would be expensive, impractical and may in any case cause undue stress to seals during their breeding season. In theory a vaccine could be used to immunise the population in the Wash which was reduced by 50% in the last outbreak. Approximately 2500 (90%) seals would require vaccination. Seals are capable of moving large distances along the UK coastline and mix with populations from Scandinavia. Thus a European wide vaccination programme would be necessary to ensure the UK population are adequately protected.
Availability and trial status of a possible vaccine
There is no known commercially available vaccine for PDV in seals. Any trial vaccine developed to immunise seals against PDV would need to be authorised for use in the UK via the Animal Test Certificate (ATC) regulations through the Veterinary Medicines Directorate of Defra. Before being used, VMD would need to be satisfied that any vaccine was of sufficient quality and safe. There are a number of other possible authorisation routes depending on the nature and source of the vaccine, but all would require evidence of adequate quality and safety.
Domestic dogs are successfully immunised against the Canine Distemper Virus (CDV). There are a number of commercially available live CDV vaccines but there are no inactivated distemper vaccines licensed in the UK, or possibly even in Europe. The use of live vaccines carries some
Page 33 risk of inducing the disease in the animal post vaccination. Inactivated vaccines often require adjuvants to produce an adequate immune response and often have a shorter duration of immunity compared to live vaccines i.e. there is no guarantee they will work for life (seals may live for 20-30 years). A genetically modified CDV vaccine has been used successfully in America to immunise susceptible non-canine species in zoos and sanctuaries. However, this group does not include phocids. A GMO could be authorised for use via an Animal Test Certificate providing the requirements of Directive 90/220 had been demonstrated. There would also be a requirement to consult with the Chemicals and GM Policy Division.
There is provision in the UK for a veterinary surgeon to administer a licensed product (under the cascade) without any specific safety studies i.e. this would permit the use of a licensed live canine distemper vaccine in seals if there was no authorised product for use in seals (VMD). However, the Institute of Animal Health, Pirbright would not recommend this course of action. A live CDV vaccine was used on the rare black-footed ferret in America with disastrous consequences (all the females of the breeding programme died following vaccination). It would be highly risky to attempt to use live CDV vaccine on seals outside controlled conditions, as it is not known how they would react. It is possible the vaccine strain itself may cause death or even cause a new epidemic amongst seals.
Following the last outbreak in 1988 a batch of dead CDV vaccine was used to successfully immunise seals at the RSPCA sanctuary in Norfolk. The batch was a one-off and there are no further supplies available. Researchers at the Seal Rehabilitation and Research Centre (SRRC), Pieterburen in Holland have been experimenting with different PDV vaccines to immunise seals in sanctuaries in Holland (Visser et.al.,1992). The vaccine is currently unavailable outside Holland possibly as a result of supplies being used to deal with the current PDV outbreak in Scandinavia. The PDV vaccines have been tested under experimental conditions and are not commercially available under licence. In normal circumstances the VMD would often require the safety of an overdose to be demonstrated before an ATC could be authorised permitting the vaccine to be used in a trial under field conditions. If it did become available there may not be sufficient quantities and it would be very expensive to vaccinate sufficient numbers of seals.
Limited vaccination within seal sanctuaries
Vaccination of a limited number of seals held in sanctuaries in the UK is an option supported by the RSPCA and International Zoo Veterinary Group. The used of dead vaccines would allow permanent seal residents to be protected and also seal pups undergoing rehabilitation to be released into the wild without risk to PDV infection and free up valuable recovery units. Experiments in Holland found that the dead vaccine affords protection from PDV and leads to long term immunity but may need to be repeated in the future. However, the seals would need to be kept in quarantine, vaccinated three times and then finally blood tested to check for antibodies. This vaccination programme would take a minimum of 2 months to turn around and it would rely on sufficient space to isolate the seals (they would need to be isolated anyway if diseased seals were brought into the sanctuary). It is not clear how this option would buy time and space in sanctuaries needed for diseased seals. The use of a live vaccine would require the seals to be kept in isolation for much longer until it is clear they do not excrete the virus. . However, while there is some support for this approach the availability of an approved vaccine remains an issue.
Further Research
Further research into vaccination of seals and the effect of vaccines on seal populations would be desirable. However, research will depend on future priorities and availability of funding. This is likely to involve trials of vaccines in isolation. The International Zoo Veterinary Group would support trials of a less virulent live CDV vaccine which contains only a single strain of the virus (currently marketed vaccines only have one distemper strain but are often multi-component vaccines with other antigens such as parvovirus and adenovirus). However, the RSPCA would need to carefully consider testing different vaccine strains in seals.
The International Zoo vet Group is exploring the possibilities of using vaccination for biosecurity measures and will keep interested parties informed of their progress. This would involve vaccination of all resident seals before moving them to disease free sanctuaries and then setting up disease only sanctuaries. However they recognise there are no guarantees that the vaccine will be effective and there are risks involved. DEFRA will keep abreast of developments in this
Page 34 area.
Conclusions
This paper has set out the current options for vaccination of seals to protect them from Phocine Distemper Virus. Administering a vaccine in the wild is largely ruled out by the practicalities and ethical considerations. Resident seals in sanctuaries could be vaccinated but a PDV vaccine is not commercially available. Canine versions of the vaccines are commercially available and in theory may be administered in isolation by a veterinary surgeon. However, there are no guarantees that the vaccine will be effective and there is a risk (in the case of live attenuated vaccines) of killing the seal.
References
Hall, A. and Harwood, J. (1995). The Intervet Guidelines to vaccinating Wildlife. NERC, Sea Mammal Research Unit, High Cross, Cambridge.
NERC Special Committee on Seals (2001). Scientific Advice on Matters Related to the Management of Seal Populations:2001
Osterhaus, A.D.M.E.; Uytdehaage, F.G.C.M.; Visser, I.K.G.; Vedder, E.J.; Reijnders, P.J.H.; Kuiper, J.; Brugge, H.N. (1988). Seal vaccination success. Nature (Lond) 337, 21.
Visser, I.K.G.; Vedder, E.J.; van de Bildt, M.W.G.; Orvell, C.; Barrett, T.; Osterhaus, A.D.M.E. (1992). Canine distemper virus ISCOMs induce protection in harbour seals (Phoca vitulina) against phocid distemper but still allow subsequent infection with phocid distemper virus-1. Vaccine; Vol.10, Issue 7.
Jensen, T.; van de Bildt, M.W.G.; Dietz, H.H.; Anderson, T. H. ; Hammer, A.S.; Kuiken, T.; Osterhaus, A.D.M.E. (2002). Another Phocine distemper Outbreak in Europe. Science. Vol 297.
Page last modified: 27 November 2002
Page 35 Appendix 2.7
Wildlife and Countryside
Home | Contact Defra | About Defra | News | Access to information | Links | Search | Site A-Z
Homepage > Wildlife & Countryside > English & European Wildlife > Seals & PDV > The options for a vaccination programme of Seals against PDV
The options for a vaccination programme of Seals against Phocine Distemper Virus (PDV) in response to predicted PDV outbreak in UK in 2002
This paper is a discussion note which explores the options to vaccinate seals against Phocine Distemper Virus (PDV) in the United Kingdom. It is a collaborative document and includes expert contributions from Animal Health, Defra, International Zoo Veterinary Group and RSPCA however it is not intended to be a scientific paper. For further technical information please contact Ian Robinson, RSPCA and Andrew Greenwood, International Zoo Veterinary Group.
It is also available here as an Adobe Acrobat pdf file (19 KB)
Summary
z A vaccination programme is considered to be a risk to both humans and seals. z Effective immunisation of the seal population in the wild is unlikely to be feasible. z An experimental vaccine exists in Holland but will not be available in the UK because it has not been tested to EU standards and there are insufficient supplies. z Vaccination of seals in sanctuaries is a reasonable possibility but seals may have to remain isolated for a lengthy period of time if the vaccine used has not been tested z If a tested vaccine was available and safe there is a possibility of vaccinating seals in sanctuaries.
Background
The last outbreak of PDV in 1988 killed over 18,000 seals in Europe. In the UK which has both common and grey seals around its coast, the populations in the Wash and Moray Firth were most effected. Common seal populations are more susceptible to the disease but have largely recovered since 1988. Those surviving exposure in 1988 will have acquired resistance to the disease. However, tests suggest that less than 10% of the population in the UK is likely to be resistant and there is potential for high mortality if an outbreak reaches the UK, particularly in the Wash. Vaccination is a possible option to reduce the number of seals affected by the virus and perhaps contain the outbreak. This paper discusses the possible options for vaccination of seals.
Knowledge of the disease
PDV is a virus similar to Canine Distemper in dogs. The virus is passed between individuals by close contact and the symptoms include respiratory problems. Death is often caused by secondary infections such as pneumonia as PDV affects the immune system. In dogs, where the dam has been exposed to natural infection or has been vaccinated, a temporary natural immunity (maternal antibody) is passed from dams to pups which may last for many weeks. Pups are either vaccinated at 8-10 weeks of age and again at 10 to 12 weeks or given a single dose of vaccine at 10 to 12 weeks of age. The booster interval for UK authorised canine distemper can be up to 2 years. Provided the immune mechanisms are the same in seals, there is transfer of maternal antibody and this passive immunity lasts for a similar period as in dogs, Veterinary Exotic Disease Division suggests that seal pups could be vaccinated to produce some protection to the individual. Whether booster vaccination would be needed would depend on the prevalence of natural infection in the population. Vaccination strategies are usually aimed at protecting populations rather than individuals. If it were required to protect an entire population then, as a rule of thumb a minimum of 60% and ideally 90% of the population would need to be vaccinated. Administering the vaccine would be possible in pups as they are easier to handle on shore than adults. If only 10% of the population of seals were exposed to PDV in the last outbreak the vast
Page 36 majority of pups born since then will not have acquired immunity and there would not be any maternal antibody to effect the vaccination. The pups are likely to respond to a vaccine at an early age but it is not clear what age the pup would need to be vaccinated. The Veterinary Exotic Disease Division is cautious of the unknown impact of administering a man-made vaccine into a wild animal population. It would need careful consideration on ethical grounds.
Practicalities of administering a vaccine
Seals are large, wild animals that spend a substantial proportion of their time at sea and haul out in remote areas to moult and pup. To attempt to catch these animals at sea would be highly dangerous and involves risking physical injury and stress to the seal. The stress of being caught may depress the seal’s immune system and make them more susceptible to infection generally. In theory seals could be caught when they are on land. It would be particularly expensive to reach these remote areas and ensure Health and Safety guidelines are followed. The ‘hauled out’ females will be particularly vulnerable to physical injury whilst giving birth and feeding young pups. The young pups would be easier to catch and handle but it is not known how the stress would affect them and how their immune systems would react to a vaccine. It is also worth noting that the environment in the Wash is not suited to catching seal pups as the sand banks only appear at low tide and common seals pups swim from birth. The RSPCA would only support attempts to pursue/catch seals on shore, if it can be guaranteed that the seals are not injured. In addition adults may flee from the breeding grounds and cause injuries to seal pups and possibly lead to their abandonment. The International Zoo Vet Group believes that vaccination of seals would cause minimal stress, especially if carried out by remote injection and the benefits of vaccination would outweigh the possible impacts of developing PDV. However, the International Zoo Vet Group regards remote injection as impractical with current technology. The RSPCA would support investigation into administering a vaccine orally (as used in wild foxes) by feeding fish or using misting spraying. However, the success of these methods is unreliable as seals do not tend to eat dead fish and the accuracy of the spraying will be variable according to weather conditions. Veterinary Exotic Disease Division have also made the point that it is not known whether existing vaccines would be effective if administered by these route.
Design of a vaccination programme - Epizootiological considerations
A vaccination programme should consider the effect of immunization on the population as a whole. The main aim of a vaccination programme should be to establish a level of immunity where the proportion of immune seals is sufficiently high to reduce the transmission of the infection to susceptible seals. The level of immunity required in seals is unknown. To ensure a suitable level is attained following basic principles the Veterinary Directorate of Defra recommends that a high proportion are immunised (60-90%). In Britain the number of common seals has been estimated at a minimum of 36,345 (NERC Special Committee on Seals) from surveys carried out between 1996 and 2000. Approximately 32,000 are found in Scotland and 4,270 in England, of which 2,785 are found in the Wash. To immunise a high proportion, 90% (32,000) of the seal population would be expensive, impractical and may in any case cause undue stress to seals during their breeding season. In theory a vaccine could be used to immunise the population in the Wash which was reduced by 50% in the last outbreak. Approximately 2500 (90%) seals would require vaccination. Seals are capable of moving large distances along the UK coastline and mix with populations from Scandinavia. Thus a European wide vaccination programme would be necessary to ensure the UK population are adequately protected.
Availability and trial status of a possible vaccine
There is no known commercially available vaccine for PDV in seals. Any trial vaccine developed to immunise seals against PDV would need to be authorised for use in the UK via the Animal Test Certificate (ATC) regulations through the Veterinary Medicines Directorate of Defra. Before being used, VMD would need to be satisfied that any vaccine was of sufficient quality and safe. There are a number of other possible authorisation routes depending on the nature and source of the vaccine, but all would require evidence of adequate quality and safety.
Domestic dogs are successfully immunised against the Canine Distemper Virus (CDV). There are a number of commercially available live CDV vaccines but there are no inactivated distemper vaccines licensed in the UK, or possibly even in Europe. The use of live vaccines carries some
Page 37 risk of inducing the disease in the animal post vaccination. Inactivated vaccines often require adjuvants to produce an adequate immune response and often have a shorter duration of immunity compared to live vaccines i.e. there is no guarantee they will work for life (seals may live for 20-30 years). A genetically modified CDV vaccine has been used successfully in America to immunise susceptible non-canine species in zoos and sanctuaries. However, this group does not include phocids. A GMO could be authorised for use via an Animal Test Certificate providing the requirements of Directive 90/220 had been demonstrated. There would also be a requirement to consult with the Chemicals and GM Policy Division.
There is provision in the UK for a veterinary surgeon to administer a licensed product (under the cascade) without any specific safety studies i.e. this would permit the use of a licensed live canine distemper vaccine in seals if there was no authorised product for use in seals (VMD). However, the Institute of Animal Health, Pirbright would not recommend this course of action. A live CDV vaccine was used on the rare black-footed ferret in America with disastrous consequences (all the females of the breeding programme died following vaccination). It would be highly risky to attempt to use live CDV vaccine on seals outside controlled conditions, as it is not known how they would react. It is possible the vaccine strain itself may cause death or even cause a new epidemic amongst seals.
Following the last outbreak in 1988 a batch of dead CDV vaccine was used to successfully immunise seals at the RSPCA sanctuary in Norfolk. The batch was a one-off and there are no further supplies available. Researchers at the Seal Rehabilitation and Research Centre (SRRC), Pieterburen in Holland have been experimenting with different PDV vaccines to immunise seals in sanctuaries in Holland (Visser et.al.,1992). The vaccine is currently unavailable outside Holland possibly as a result of supplies being used to deal with the current PDV outbreak in Scandinavia. The PDV vaccines have been tested under experimental conditions and are not commercially available under licence. In normal circumstances the VMD would often require the safety of an overdose to be demonstrated before an ATC could be authorised permitting the vaccine to be used in a trial under field conditions. If it did become available there may not be sufficient quantities and it would be very expensive to vaccinate sufficient numbers of seals.
Limited vaccination within seal sanctuaries
Vaccination of a limited number of seals held in sanctuaries in the UK is an option supported by the RSPCA and International Zoo Veterinary Group. The used of dead vaccines would allow permanent seal residents to be protected and also seal pups undergoing rehabilitation to be released into the wild without risk to PDV infection and free up valuable recovery units. Experiments in Holland found that the dead vaccine affords protection from PDV and leads to long term immunity but may need to be repeated in the future. However, the seals would need to be kept in quarantine, vaccinated three times and then finally blood tested to check for antibodies. This vaccination programme would take a minimum of 2 months to turn around and it would rely on sufficient space to isolate the seals (they would need to be isolated anyway if diseased seals were brought into the sanctuary). It is not clear how this option would buy time and space in sanctuaries needed for diseased seals. The use of a live vaccine would require the seals to be kept in isolation for much longer until it is clear they do not excrete the virus. . However, while there is some support for this approach the availability of an approved vaccine remains an issue.
Further Research
Further research into vaccination of seals and the effect of vaccines on seal populations would be desirable. However, research will depend on future priorities and availability of funding. This is likely to involve trials of vaccines in isolation. The International Zoo Veterinary Group would support trials of a less virulent live CDV vaccine which contains only a single strain of the virus (currently marketed vaccines only have one distemper strain but are often multi-component vaccines with other antigens such as parvovirus and adenovirus). However, the RSPCA would need to carefully consider testing different vaccine strains in seals.
The International Zoo vet Group is exploring the possibilities of using vaccination for biosecurity measures and will keep interested parties informed of their progress. This would involve vaccination of all resident seals before moving them to disease free sanctuaries and then setting up disease only sanctuaries. However they recognise there are no guarantees that the vaccine will be effective and there are risks involved. DEFRA will keep abreast of developments in this
Page 38 area.
Conclusions
This paper has set out the current options for vaccination of seals to protect them from Phocine Distemper Virus. Administering a vaccine in the wild is largely ruled out by the practicalities and ethical considerations. Resident seals in sanctuaries could be vaccinated but a PDV vaccine is not commercially available. Canine versions of the vaccines are commercially available and in theory may be administered in isolation by a veterinary surgeon. However, there are no guarantees that the vaccine will be effective and there is a risk (in the case of live attenuated vaccines) of killing the seal.
References
Hall, A. and Harwood, J. (1995). The Intervet Guidelines to vaccinating Wildlife. NERC, Sea Mammal Research Unit, High Cross, Cambridge.
NERC Special Committee on Seals (2001). Scientific Advice on Matters Related to the Management of Seal Populations:2001
Osterhaus, A.D.M.E.; Uytdehaage, F.G.C.M.; Visser, I.K.G.; Vedder, E.J.; Reijnders, P.J.H.; Kuiper, J.; Brugge, H.N. (1988). Seal vaccination success. Nature (Lond) 337, 21.
Visser, I.K.G.; Vedder, E.J.; van de Bildt, M.W.G.; Orvell, C.; Barrett, T.; Osterhaus, A.D.M.E. (1992). Canine distemper virus ISCOMs induce protection in harbour seals (Phoca vitulina) against phocid distemper but still allow subsequent infection with phocid distemper virus-1. Vaccine; Vol.10, Issue 7.
Jensen, T.; van de Bildt, M.W.G.; Dietz, H.H.; Anderson, T. H. ; Hammer, A.S.; Kuiken, T.; Osterhaus, A.D.M.E. (2002). Another Phocine distemper Outbreak in Europe. Science. Vol 297.
Page last modified: 27 November 2002
Page 39 Appendix 2.8
Department for Environment, Food and Rural Affairs Seals and Phocine Distemper Virus (PDV)
Public health guidance note issued by the Scottish Centre for Infection and Environmental Health
BACKGROUND
The morbilliviruses form part of the family of paramyxoviruses, members of which infect humans and many species of animals, including terrestrial and aquatic mammals, birds and reptiles. There are seven different species of morbillivirus, including the phocine distemper virus (PDV) currently causing seal deaths in European waters, particularly in Denmark. Other animals, which can be infected with similar (but different) viruses, include dolphins and dogs, where the virus causes canine distemper against which most pet dogs are vaccinated.
Since June 2002, PDV has accounted for over 2000 seal deaths around the Danish and Swedish coasts. A widespread outbreak in the UK cannot be ruled out. Seal deaths have been reported and the virus has now been isolated.
The virus was first identified in 1988, when an epizootic occurred resulting in more than 18,000 deaths in seals. PDV is extremely contagious and is transmitted via close contact or the air-borne (droplet or aerosol) route. It affects the immune system of the seal, leaving it susceptible to other infections. Signs of infection include respiratory problems, coughing, nasal discharge, a reluctance to move, subcutaneous emphysema (air under the skin) around the head and neck and possibly problems of the nervous system.
HUMAN HEALTH RISKS
PDV has never been recorded as a cause of human illness, either during this current outbreak or during previous epizootics in seals.
However sick, dying or dead seals may be more accessible to the general public and consequently there may be increased contact between people and seals. This increases the opportunity for other infectious organisms associated with seals to cause human infections, particularly through infected bites and wounds.
PRINCIPLES OF GOOD PRACTICE
Occupational groups at Risk
Occupational groups that come into contact with sick and dying seals are at greater risk than the general public. This includes those working for or on a voluntary basis for animal welfare organisations involved in the collection, treatment and management of seals. Those with responsibility for disposing
Page 40 of the carcases of dead seals are also at increased risk. Where there is any possibility of exposure, workers should be made aware of possible risks and protective measures that can be taken to reduce these risks.
Protective measures include:
z Good personal hygiene should be observed at all times with particular attention to hand washing z Personal protective clothing i.e. heavy-duty gloves, boots and ideally goggles should be made available for workers. z After use all protective clothing should be washed with soap and warm water and disinfected. Rinse in clean water and dry items thoroughly. z Following any injury, such as a bite, medical advice should be obtained as soon as possible. z Any unusual illness should be reported to the medical adviser.
Members of the public:
Members of the public are advised to avoid contact with live or dead seals. To protect the health of dogs they should be not be allowed to come in contact with seals or seal carcases. Anyone coming into contact with a sick or dead seal should be aware of the possible risks and take appropriate measures to reduce these risks:
Preventative measures include:
z Members of the public should not handle injured or sick seals or seal carcases, but should contact the specialist services of animal welfare groups such as the SSPCA. z If against this advice there is contact with seals personal hygiene should be of paramount importance with attention to hand washing using soap and running water z Following any injury, such as a bite from a seal, medical advice should be sought immediately.
USEFUL CONTACT
In the first instance, all calls concerning stranded seals, whether alive or dead, should be made to the UK National Seals Helpline at 08712 447999.
Callers reporting sick or dead seals should note the exact location of the animal and any signs of illness that have been observed. Details will be passed to the appropriate bodies, including the SSPCA and the Scottish Agricultural College.
Updated 29 August 2002
Return to Wildlife, Countryside and Flood Management Index
Return to DEFRA Home Page
Page 41 • Appendix 3
GUIDELINES FOR VOLUNTEER SEAL SURVEYORS
What information should I collect on the beach?
Before starting your first beach survey, please consult the important health and safety recommendations in Section I of these guidelines.
Species Identification
• Identify the species of seal where possible (See Section II); otherwise record species as “unidentified”.
• There are two resident seal species in the UK, the common seal (Phoca vitulina) and the grey seal (Halichoerus grypus). The common seal is sometimes known as the harbour seal. The two species (grey and common) can be differentiated using the following characteristics (See Section II):
• Attempt species identification using the guidelines above. Visual inspection alone should be used to assess head and nose shape, nostril and coat appearance.
Body Measurements
• Body measurements should be recorded as accurately as possible in centimetres. • No attempt should be made to touch, move or reposition the seal for these measurements. • A tape measure should be laid parallel to the carcass to take the readings. • The head- hind flipper length (1) should be measured from the tip of the nose to the end of the hind flippers. (See diagram below) • The head-tail length (2) should be measured level from the tip of the nose to the end of the tail. (See diagram below) • Whilst the details of partial carcasses should be recorded as far as possible, body measurements should not be attempted.
Carcass Condition
• Estimate the degree of decomposition according to the following scheme:
“Fresh” – recently died, eyes present, no / little scavenger damage “Some decomposition” – eyes may be absent, moderate scavenger damage “Advanced decomposition” - carcass disintegration (e.g. skeletal remains, mummified)
Phocine Distemper Virus Epizootic Investigation 2002/2003 1 Photographs
• Where volunteers have the available camera equipment, it would be very useful if they were able to take photographs of the seals that they have reported. Digital images may be e- mailed along with their weekly survey report. This will help provide additional information for future study. Unfortunately funds are not currently available to reimburse volunteers for the costs of photography and this is therefore left entirely at the volunteer’s discretion. If volunteers are willing to take photographs it is important that these are appropriately labelled and your national co-ordinator should be contacted for further advice.
How do I record and report the survey results?
• Record the date on which the survey was performed. Please note that it is important that all survey results, whether or not dead seals were found, should be reported.
• Volunteers should record details of the species, body measurements and carcass condition for each seal found within their nominated survey area.
• Where possible, the data should be introduced into fields of the attached Excel spreadsheet and be sent via e-mail to your regional co-ordinator in combination with your personal details, unique Volunteer Reference Number and the grid reference of the start and finish of your survey area. Alternatively, results can be relayed by telephone or fax as convenient.
• Pass all information to your co-ordinator as soon as possible after contacting your ‘safety contact’. This will enable the information you have gathered to be quickly included in the national seal strandings database. The National Co-ordinator will also report the seal carcasses to the Local Authority so that they can be safely removed from the beach.
• It is very important that dead seals once counted are not recounted in subsequent surveys. Note any readily identifiable distinguishing marks on the seal itself and its local environment. If this is likely to be a problem, please contact your national co-ordinator for further advice.
Section I - General Health & Safety Aspects
• Although phocine distemper is not infectious to humans, seals may harbour, or be infected, with other diseases that can be transmitted to humans.
• As a consequence, volunteers are advised to never touch, attempt to move, or reposition a seal carcass.
• Volunteers must be over the age of eighteen years.
• In the event of any illness, consult with your doctor and explain that you have been in the vicinity of marine mammals since this may be important in diagnosing or treating the complaint.
• Wash hands as soon as possible after surveying and before eating, drinking or smoking.
• Wearing of Wellington boots or other similar easily disinfected footwear during the survey is advised.
• Live seals, even if sick, are strong, can inflict serious bite wounds, and should never be approached by members of the public. Carefully observe all seals on the beach before approaching them to be sure that they are dead. All live sick seals should be reported to the appropriate rescue organisation immediately by ringing the National Seal Hotline Number 08712 447999.
Phocine Distemper Virus Epizootic Investigation 2002/2003 2 • Dogs are at risk of infection from phocine distemper virus unless vaccinated against canine distemper. It is recommended that volunteers do not take their dogs with them during seal surveys. It is advised that any dogs which volunteers are likely to be in contact with over the period of the survey have up-to-date vaccination against distemper virus. Consult your local veterinarian for further advice.
• If your dog does have contact with a dead or sick seal and develops signs of illness, consult your local veterinarian for advice as soon as possible.
• Be aware of any other hazardous items in the strandline, such as discarded syringes, broken glass, rusty nails in flotsam etc.
• Volunteers are strongly advised to ensure that the beach or coastal area they survey is safe.
• If lone surveying, establish contact with someone (‘safety contact’) who knows where you are going, what time you are going and what time you are expected back.
• Do not forget to notify your ‘safety contact’ on return.
• Agree a time delay after which the situation becomes an emergency (or the ‘safety contact’ becomes concerned due to changing weather conditions etc) and the ‘safety contact’ informs the Coastguard.
• Do not survey dangerous areas e.g. soft mud, areas cut off by the tide or under unstable cliffs; consult tide tables.
• If in an area of good coverage a mobile phone can be a useful lifeline, or some other method of signalling, e.g. pocket flares.
• It is important to wear appropriate clothing to prevent wind chill. Wear hi-visibility clothing.
Phocine Distemper Virus Epizootic Investigation 2002/2003 3 Section II
Seal Species Identification Guide
Common seal Grey seal (or Harbour seal) Halichoerus gryphus Phoca vitulina
Head – Front view
Head – Side view
Phocine Distemper Virus Epizootic Investigation 2002/2003 4 • Appendix 4.1
REVISED GUIDELINES FOR THE POSTMORTEM EXAMINATION AND TISSUE SAMPLING OF SEALS DURING THE 2002 PDV EPIZOOTIC
CONTENTS
1. Postmortem a) External examination b) Evisceration c) Examination of organs of head, neck and thorax d) Examination of abdominal organs e) Samples for various studies
2. Storage, collection and despatch of samples a) Labelling of samples b) Blubber, liver and kidney samples for organohalogenated compounds and heavy metal levels c) Histological samples d) Parasites
1. POSTMORTEM
All structures must be examined visually and by palpation, making incisions into the organs. The minimum incisions are indicated below. A full post mortem record must be kept, if possible on the standard "seal postmortem report" form. a) EXTERNAL EXAMINATION
The species of seal should be ascertained and the sex noted.
The animal should be weighed and the following measurements taken: -length from tip of nose to tip of hind flipper, -length from tip of nose to end of tail (both in a straight line), -girth just behind front flippers -the mid-sternal blubber depth (after making a small incision).
The skin should be examined and any alopecic areas or other abnormalities should be noted and a sample preserved in formalin.
Examine the eyes especially for conjunctivitis, corneal opacity or ulceration.
Examine the mouth looking particularly for tongue ulceration, missing teeth and diseased teeth. Feel along both mandibles for osteomyelitis due to tooth root infection. b) EVISCERATION
Make a longitudinal incision along the ventral surface of the animal from the symphysis of the mandible to the anus or vulva and reflect the skin from the sides of the animal noting the appearance of the mammary tissue in females and the milk in lactating animals. Two full thickness blubber samples should be taken from the sternal region, the samples should be about 20 g each and should be placed in two Sovirel glass tubes (these should be about 3/4 full) or aluminium foil and stored at -200C. Open the abdominal cavity by removing the lower part of the abdominal wall, as you do so note if there is a persistent urachus. Open the chest by removing the lower part of the chest wall using bone shears.
Phocine Distemper Virus Epizootic Investigation 2002/2003 1 Aseptically take a 1cm3 section of tissue from the lung, spleen and bronchial lymph node for PCR and store at –700C (-200C if necessary). If the carcass is reasonably fresh the liver, one kidney and one lung should also be examined bacteriologically.
Remove the stomach and intestine from the carcass by severing the oesophagus, root of the mesentery and the rectum. In females remove the ovaries and the entire reproductive tract. Remove the liver and kidneys and adrenals, preserving both adrenals in formalin. Loosen the tongue from between the mandibles and work down the neck to remove the oesophagus and trachea (with the tongue attached) and work into the chest to remove the heart and lungs. Examine the pharynx and the back of the nasal chambers for the presence of mites.
Open the bladder and note the appearance of the urine. Take a sample of bladder in 10% formalin for histopathology. c) EXAMINATION OF ORGANS OF HEAD, NECK AND THORAX
Once the viscera have been removed from the carcass start examining them.
If possible, the brain should be examined by removing the top of the cranium with a large saw or oscillating saw. A 1 cm3 section of brain should be taken aseptically for PCR and preserved in a small vial at –700C (or –200C if necessary). The whole brain, or 1cm3 sections of cerebrum and cerebellum, should be preserved in 10% formalin.
Note the appearance of the thyroid and place a sample in formalin. Open the oesophagus along its entire length, any nematodes found should be preserved in ethanol. Open the trachea and its major branches and make several incisions into the substance of the lungs, any nematodes should be placed in ethanol. Preserve in formalin the left bronchial lymph node and a piece of lung (about 1 cm3) from the upper posterior border of the left and right apical lobe.
Examine the thymus, if present and place 1 cm3 in formalin.
Collect any serum present in the heart lumen (or elsewhere), even if it is haemolytic, and freeze.
Separate the heart from the lungs and holding the right side of the heart in the left hand cut the left ventricle open parallel to the coronary groove and about 1 cm from it. Open the origin of the aorta by incising under the relevant valve cusp. Open the right side of the heart by incising the same distance from the coronary groove but on the other side, extending this incision into the origin of the pulmonary artery. Returning to the apex of the heart make a second incision about halfway between the two coronary grooves to go through the right atrio-ventricular valve. Join the two incisions in the right ventricle close to the apex of the heart. Examine both chambers of the right side of the heart for nematodes, these may well be intertwined with the bundles of the myocardium and a little difficult to see, any present should be placed in ethanol. d) EXAMINATION OF ABDOMINAL ORGANS
Remove the spleen from the stomach and examine it. Seals' spleens usually have a number of clefts in them. Preserve a piece of the ventral tip of the spleen (about 1 cm3) in formalin.
Examine the liver making numerous grooves into the substance looking particularly for areas of fibrosis and thickened bile ducts. After examination fill aluminium foil or two Sovirel glass tubes about 3/4 full (about 20 g in each) with cross-sectional samples of liver tissue and freeze. Place 1 cm3 of liver tissue in formalin.
Incise and examine the kidneys. After examination fill aluminium foil or two Sovirel glass tubes about 3/4 full (about 20 g in each) with cross-sectional samples of kidney tissue and freeze. Place 1 cm3 from a kidney in formalin.
Examine the ovaries and incise the vagina, cervix and the uterine horns along their entire length looking particularly for evidence of uterine stenosis and occlusions. If these are found place the affected portion in formalin. Any foetus and its placenta should be frozen in aluminium foil. The ovaries should be preserved in formalin. Phocine Distemper Virus Epizootic Investigation 2002/2003 2
In males incise the testes, examine the cut surface and then place the entire organs (or a cross-sectional slice about 0.5cm thick after weighing the whole organs) in formalin.
Separate the stomach from the intestines and open it along the greater curvature. The nematodes should be placed in ethanol; look for the ulcers that they frequently cause. Examining the mucosa closely, especially between the mucosal folds, remove fish, squid beaks, fragments of shellfish shells, otoliths, and other food material and store frozen.
Straighten out the entire intestine and examine it along the full length. Collect otoliths and any other recognisable food remains in ethanol (or alternatively freeze). Acanthocephalid worms (most likely to be found in the lower jejunum and ileum) and cestodes should be placed in ethanol. Very small trematodes have also been found in the intestines of seals. A full thickness sample from the middle of the mesenteric lymph node should be put in formalin. e) SAMPLES FOR VARIOUS STUDIES
Take a 4 cm2 piece of skin from between the digits and freeze. Remove one lower canine or a sample of the lower jaw including the teeth and its root and preserve frozen. It is not unknown for both lower canines to be missing, in this case take one of the upper ones.
In addition to the samples mentioned above, lesions in any other organs should be preserved in formalin after taking a sample for bacteriological examination from any purulent material. If a viral infection is suspected samples from the relevant organs should also be frozen at -700C for virus isolation. Any abnormalities should also be photographed.
Phocine Distemper Virus Epizootic Investigation 2002/2003 3 • Appendix 4.2
SEAL POSTMORTEM REPORT
When this report has been completed, please send a copy to: Marine Mammal Strandings Project, Veterinary Science Division, Institute of Zoology, Regent's Park, London NW1 4RY, Tel: 020 7449 6691 or 6672 Fax: 020 7586 1457 email: [email protected] or [email protected]
SS NO. : ...... PM NO. : ......
SPECIES :...... SEX :......
LOCATION FOUND :......
DATE FOUND :...... FOUND BY : ......
......
PATHOLOGIST :...... DATE OF PM : ......
FROZEN?: Y / N
CARCASS CONDITION:
BODY CONDITION USING CONDITION CODE :. . . . . Condition code: 1) live (becomes code 2 at death) 4) advanced decomposition (major bloating, skin 2a) extremely fresh (as if just died, no bloating, meat is peeling, penis extended in males, organs beyond considered by most to be edible) recognition, bones exposed due to decomposition) 2b) slight decomposition (slight bloating, blood 5) indeterminate (mummified carcass or skeletal imbibition visible) remains, no organs present) 3) moderate decomposition (moderate bloating, skin peeling, penis may be extended in males, organs still intact, excluding postmortem damage)
1. BASIC MEASUREMENTS LENGTH, GIRTH AND BLUBBER PHOTOGRAPHS TAKEN THICKNESS: -lateral views of whole body, both sides: Y / N -other photographs (list): -tip of nose to tip of hind flipper (cm) (1): - - -tip of nose to end of tail (cm) (2): -girth behind front flippers (cm) (3):
BODY WEIGHT (kg): -mid-sternal blubber thickness (mm) (4):
Phocine Distemper Virus Epizootic Investigation 2002/2003 4 2. GROSS POSTMORTEM
Encircle the appropriate category: NE = not examined NAD = nothing abnormal detected A = abnormal (describe fully overleaf)
EXTERNAL EXAMINATION ABDOMINAL CAVITY
-nutritional state NE NAD A -liver (describe) NE NAD A -peritoneum/peritoneal cavity NE NAD A -body orifices (mouth, eyes, ear openings, ALIMENTARY TRACT nose, anus, genital slit) NE NAD A -mouth NE NAD A -ectoparasites NE NAD A -oesophagus NE NAD A -flippers NE NAD A -stomach NE NAD A -small intestine INTEGUMENT NE NAD A -large intestine NE NAD A -anus NE NAD A -skin NE NAD A -blubber UROGENITAL SYSTEM NE NAD A -subcutaneous tissue NE NAD A -mammary glands NE NAD A -ovaria/testes (describe) (describe) NE NAD A -uterus NE NAD A -vagina/penis MUSCULOSKELETAL SYSTEM NE NAD A -kidneys NE NAD A -ureters NE NAD A -skull NE NAD A -urinary bladder NE NAD A -other bones NE NAD A -urethra NE NAD A -back muscle mass NE NAD A -other muscles LYMPHATIC/ENDOCRINE SYSTEMS
NERVOUS SYSTEM NE NAD A -adrenals NE NAD A -pancreas NE NAD A -brain NE NAD A -thyroids NE NAD A -spinal cord NE NAD A -spleen NE NAD A -peripheral nerves NE NAD A -thymus NE NAD A -lymph nodes CARDIOVASCULAR SYSTEM NE NAD A -tonsils
NE NAD A -pericardial sac NE NAD A -myocardium NE NAD A -valves NE NAD A -arteries, veins
RESPIRATORY SYSTEM
NE NAD A -nasal cavity NE NAD A -sinuses NE NAD A -trachea, bronchi NE NAD A -lungs NE NAD A -pleura Phocine Distemper Virus Epizootic Investigation 2002/2003 5 DESCRIPTION OF ABNORMALITIES GROSS POSTMORTEM (add extra pages if necessary):
PRELIMINARY DIAGNOSIS (in order of importance):
a.
b.
c.
d.
e.
3. RESULTS OF HISTOLOGY (add extra pages if necessary)
4. RESULTS OF BACTERIOLOGY
5. MISCELLANEOUS RESULTS
6. FINAL DIAGNOSIS (in order of importance)
a.
b.
c.
d.
e.
Phocine Distemper Virus Epizootic Investigation 2002/2003 6
7. CHECKLIST SAMPLES
For sending samples, please contact Paul Jepson, Department of Veterinary Science, Institute of Zoology, Regent's Park, London NW1 4RY, UK, Tel: 020 7449 6691 or 6672 Fax: 020 7586 1457 email: [email protected] or [email protected] a) STANDARD SAMPLES
In each square, enter: P = sample taken Blank = sample not taken or not present Record any extra samples taken in section b.
Phocine Distemper Virus Epizootic Investigation 2002/2003 7
Freeze at -200C 10% Formalin blubber 2 x 20g abnormalities female epidermis 4 cm2 reproductive tract all foetus/placenta whole adrenal gland one kidney 2 x 20 g brain whole or 1cm3 liver 2 x 20g bronchial lymph node 1 cm3 muscle 2 x 20g heart 1 cm3 serum (also haemolytic) up to 20 ml kidney 1 cm3 canine teeth 2 liver 1 cm3 lung 4 x 1 cm3 mesenteric ln. 1 cm3 0 Virology (freeze at -70 C) bladder 1 cm3 3 brain 1 cm ovaries both 3 bronchial lymph node 1 cm spleen 1 cm3 3 spleen 1 cm testis 1 cm3 3 lung 1 cm thymus 1 cm3
thyroid 1 cm3
Bacteriology kidney swab/block liver swab/block lung swab/block
Phocine Distemper Virus Epizootic Investigation 2002/2003 8 b) EXTRA SAMPLES
Extra samples of lesions taken for histological examination (list):
- -
- -
- -
- -
- -
Extra samples of lesions taken for bacteriological examination (list):
- -
- -
- -
Other extra samples taken (list):
- -
- -
- -
- -
Phocine Distemper Virus Epizootic Investigation 2002/2003 9
• Appendix 5.1
The Zoological Society of London (ZSL) urgently appeals for volunteers to monitor UK coastlines
The first reported case of seal Phocine Distemper Virus (PDV) has been confirmed outside The Wash and, as feared, the virus is continuing to spread along British coastlines to other seal populations.
ZSL, co-ordinators of current government funded research, are appealing for volunteers in around the country to report dead seals found along their local coastlines to enable their scientists to collate information about the U.K. outbreak.
Volunteers will be requested to walk a kilometre stretch of their local beach on a weekly basis looking for dead seals and report their findings to a national co-ordinator. This important data will be used to learn more about PDV and how to conserve the UK seal population in the future.
The current epidemic, first identified in May 2002, originated on the island of Anholt in the Kattegat, the stretch of water between Denmark and Sweden, where it has already killed thousands of animals. Since then it has spread along the Dutch and German coasts, reaching Lincolnshire and East Anglia on 13th August 2002.
There are two species of seal resident in the UK; the harbour seal (or common seal) and the grey seal. Although past evidence shows that PDV has infected species including harp, grey and harbour seals, the only species to have suffered large scale mortality in Europe is the harbour seal. The 1988 European PDV outbreak that spread from the Baltic to Ireland killed an est1mated 18,000 harbour seals.
Paul Jepson, Wildlife Pathologist, and co-ordinator of the research team at ZSL’s Institute of Zoology commented “We have been collating results from volunteers all over the country and we have found the information invaluable so far. However we need more volunteers who will be able to gather information to complete the research.”
“We understand the effects of PDV on seals, however, the current research will provide us with more information on the rate of infection along British coastlines and which seal colonies are most severely affected,” concluded Paul Jepson.
Members of the public interested in becoming a volunteer should email [email protected].
Notes to editors
The institute of Zoology, carries out ZSL’s scientific research. Founded in 1826, the Zoological Society of London (ZSL) is an international scientific, conservation and educational charity focusing on conservation of animals and their habitats. ZSL runs London Zoo and Whipsnade Wild Animal Park, and together with its scientific research is actively involved in world-wide field conservation.
For further information about the Zoological Society of London and the Institute of Zoology please contact [email protected]
Phocine Distemper Virus Epizootic Investigation 2002/2003 1
About the research project
The Department for Environment, Food and Rural Affairs, Scottish Executive and Welsh Assembly are funding the nine-month research project that is being led by the Institute of Zoology. Its aim is to find out more about the impact of Phocine Distemper Virus (PDV) which killed about 18,000 common seals and about 400 grey seals when it last struck in 1988.
Other groups involved in the research include: • The Royal Society for the Prevention of Cruelty to Animals • The Scottish Society for the Prevention of Cruelty to Animals • Scottish Executive Environment Rural Affairs Department • National Assembly of Wales Agriculture Department • The Department for Environment Food and Rural Affairs • The Department of Environment (Northern Ireland) • The Sea Mammal Research Unit
What are volunteers asked to do?
Volunteers are requested to select an area of safe coastline in their local area which they will be able to survey for dead seals once a week. It is important that each volunteer walks the same stretch of coastline for each survey so that the most useful information can be collected for analysis. Surveys can be performed at any time of day convenient for the volunteer whilst considering their safety with the timing of local tides. The most important information to collect is the number of dead seals found within the study area. To gain maximum information from the survey, it is important to report all survey results, whether or not dead seals are observed.
FURTHER INFORMATION ABOUT PDV How does the virus spread? It spreads between seals mainly through coughing whereby other seals inhale the virus. Dung, mucus and food waste can also harbour residues of the virus.
Is the virus dangerous to humans? The virus itself does not present a danger to public health. However, pathogens such as bacterial infections can develop in the carcasses of the seals as in other animals, which present a risk to health. It is therefore advisable not to touch dead seals.
Can I still go to the beach? There is no reason to avoid the beach as long as you steer clear of any dead or dying animals on the beech. If the animal is still alive, do not approach it as it could bite or carry pathogens (other than the virus) which could be harmful to your health. You should never touch a dead animal - ring the helpline - 08712 447999
What do I do if I've touched a sick or dying seal? The virus itself is not dangerous to people, but the seal could be harbouring other bacterial or viral infections which are transmittable to people. If you do contract certain symptoms, it is important to tell your doctor you have been in contact with a sick or dying seal. It is important to remember that a live seal can inflict quite a serious wound on a human.
Is the virus dangerous to animals? The virus can infect dogs. Pet owners need to be aware of this. Dogs with up-to-date vaccination against canine distemper are not at risk.
Is there a risk of an epidemic among fish or birds? No, the virus is not transmitted to fish or birds.
Phocine Distemper Virus Epizootic Investigation 2002/2003 2 • Appendix 5.2
Phocine Distemper Virus Call for volunteers interview log
Publication Date Contact Status 1. London Tonight Monday 22nd Elka Interviewed Paul Jepson (PJ) in the September Post Mortem Room 2. BBC South East Wednesday 26th Peter Whittlesea Wanted expert in Kent to come and September film on the coast. Got a contact from local uni – using our story and call for appeal 3. BBC Radio Wednesday 26th Francesca Williams Pre-recorded interview with Paul Newcastle September Jepson 4. BBC Radio Wednesday 26th Zara Pre-recorded interview with Paul Lincolnshire September Jepson 5. Tyne/ Tees TV Wednesday 26th Nigel Green Found expert to go live September 6. Radio 4 – Today Friday 27th Bob Walker Interview with Paul Jepson programme September 7. Evening Standard Thursday 26th Geraint Smith Article for Friday 27th September 8. The Times Thursday 26th Steve Bird Article for Friday 27th September 9. BBC Wildlife For November Issue Magazine 10. LBC Friday 27th Pre-record for drive time show September 11. The Independent Friday 27th Cahal Milmo Brief interview with PJ for sat or mon September edition 12. BBC Radio Cornwall Monday 30th James Churchfield Live interview with PJ September 13. The Journal Thursday 31st Graeme Whitfield Brief telephone interview with Paul (Newcastle) October Jepson
Phocine Distemper Virus Epizootic Investigation 2002/2003 3 • Appendix 5.3
Phocine Distemper Virus
Coverage log
Title Publication Circulation Area of Date Coverage Seal Virus Reaches the UK Veterinary Record -- National 31/08/02 Animal Health News and Reports 151(9): 250 Resurgence of seal-killing Veterinary Times -- National 02/09/02 disease 32B:1 Fears of disease spreading to Hull Daily Mail (First) 82,431 Hull and East 11/09/02 coast Riding Fears of disease spreading to Hull Daily Mail (Final) 82,431 Hull and East 11/09/02 coast Riding Deadly seal virus may have Yorkshire Post 78,779 Hull and East 11/09/02 reached Yorkshire Riding Virus kills more than 1,000 The Times 718,878 National 12/09/02 seals in coastal waters Dead seal is washed up East Anglian Daily Times 47,229 Norfolk/ Suffolk 13/09/02
Suspected case of Phocine Beverley and East Yorkshire 20,695 East Yorkshire 12/09/02 Virus Advertiser Dead seal is washed up East Anglian Daily Times 44,000 Essex 13/09/02 (Essex) Killer virus has struck seal Dover Mercury 13,849 Kent 19/09/02 colony Killer virus has struck seal East Kent Mercury 13,849 Kent 19/09/02 colony Fears for seals after virus Evening Gazette 28,468 Essex 19/09/02 hits (Colchester) Reports of dead seals Veterinary Record -- National 21/09/02 continue to rise Animal Health News and Reports 151(12): 340 Seal virus fears Express and Echo (Exeter) 31,000 Exeter 23/09/02
The killer disease now Thanet Times 10,707 Kent 24/09/02 threatening our seals Deadly seal virus could hit Mourne Observer (Down 11,952 Ireland 25/09/02 County Down shoreline edition) Slim chance of a happy end Eastern Daily Press (City) 74,832 Norfolk 26/09/02 (Norwich) Slim chance of a happy end Eastern Daily Press (West 74,832 West Norfolk 26/09/02 Norfolk & Fens) Killer seal virus may strike Hartlepool Mail (final 24,263 Hartlepool 27/09/02 dogs edition) Deadly virus spells disaster Evening Standard 424,225 London 27/09/02 for Britain’s seal population Deadly seal virus spreading North West Evening Mail 20,315 Cumbria 28/09/02 (Cumbria) Epidemic plea Sunday Sun 97,624 Newcastle 29/09/02
Plea for seal watch Daily Post 70,019 Cheshire 30/09/02
Phocine Distemper Virus Epizootic Investigation 2002/2003 4 Plea for seal watch Daily Post 24,018 Merseyside 30/09/02
Dog owners warned over Yorkshire Post 73,876 North Yorkshire 01/10/02 seal virus Dog owners warned over Yorkshire Post 73,876 Hull and East 01/10/02 seal virus Riding Dog owners warned over Yorkshire Post 73,876 West Riding 01/10/02 seal virus You could help save our Evening Chronicle 99,389 Newcastle 03/10/02 seals Dog warning as seal virus Evening News 70,205 Edinburgh 05/10/02 heads for Forth Appeal for volunteers to The West Briton Truro and 51,291 Cornwall 10/10/02 monitor seals mid Cornwall Edition Help is needed in seal crisis Hull Daily Mail First 82,431 Hull and East 12/10/02 Riding Help is needed in seal crisis Hull Daily Mail Final 82,431 Hull and East 12/10/02 Riding Seal toll rises Hull Daily Mail First 82,431 Hull and East 23/10/02 Riding Seal toll rises Hull Daily Mail Final 82,431 Hull and East 23/10/02 Riding Two-thirds drop in number if Eastern Daily Press 74,832 West Norfolk and 25/10/02 sick seals Fens Two-thirds drop in number if Eastern Daily Press 74,832 Norwich 25/10/02 sick seals Save our seals English Nature Magazine -- National November 2002 Seal virus “looks on the Great Yarmouth Mercury 19,951 Great Yarmouth 01/11/02 decline” 80 seals die as virus strikes The Journal 47,146 Newcastle 01/11/02
Deadly virus hits wildlife Gazette (South Shields) 23,341 Newcastle 06/11/02
PDV takes out UK seals Mammal News Quarterly -- National Winter 2002 Newsletter of The Mammal Society Wildlife Diseases – PDV in mammals uk, Quarterly -- National Winter 2002 common seals magazine of Mammals Trust UK Cold snap saves seals The Independent -- National 10/01/03 threatened by virus
Return to the Sea Veterinary Record -- National 01/02/03 Animal Health News and Reports Veterinary Record 152(5): 123 Le’s hope its run its course – Lifewatch magazine -- National Spring 2003 the work of the Seal Strandings Project PDV Epidemic in Seals mammals uk, Quarterly -- National Spring 2003 magazine of Mammals Trust UK Seal virus has burned out for Eastern Daily Press (West 74,832 Norfolk 13/06/03 now Norfolk & Fens)
Phocine Distemper Virus Epizootic Investigation 2002/2003 5
• Appendix 5.4 - National Seal Hotline, Greenland Interactive Ltd
Week starting N u m b er o f C alls A v erage D u ratio n o f C alls T o tal D u ratio n o f C alls 13.08.2002 188 1m 38s 307m 17s 19.08.2002 308 1m 51s 571m 5s 26.08.2002 511 1m 26s 735m 11s 02.09.2002 317 1m 33s 492m 56s 09.09.2002 432 3m 55s 1695m 53s 16.09.2002 510 1m 38s 837m 53s 23.09.2002 347 1m 38s 571m 42s 30.09.2002 237 1m 56s 459m 56s 07.10.2002 333 1m 57s 654m 22s 14.10.2002 222 1m 41s 374m 59s 21.10.2002 115 1m 39s 190m 3s 28.10.2002 67 2m 7s 14m 4s 04.11.2002 71 1m 45s 124m 29s 11.11.2002 61 1m 51s 112m 52s 18.11.2002 57 1m 56s 111m 5s 25.11.2002 57 1m 49s 104m 13s 02.12.2002 43 1m 58s 85m 8s 09.12.2002 45 1m 19s 59m 58s 16.12.2002 23 2m 10s 50m 6s 23.12.2002 25 1m 43s 43m 11s 30.12.2002 47 3m 2s 143m 17s 06.01.2003 28 1m 37s 45m 21s 13.01.2003 16 1m 33s 24m 55s 20.01.2003 25 2m 13s 55m 40s 27.01.2003 25 2m 3s 51m 25s 03.02.03 23 1m 59s 45m 39s 10.02.03 9 1m 16s 11m 26s 17.02.03 18 2m 28s 44m 25s 24.02.03 21 1m 26s 30m 10s 03.03.03 11 1m 33s 17m 08s 10.03.03 12 0m 30s 06m 9s 17.03.03 11 0m 35s 06m 31s 24.03.03 7 0m 33s 3m 57s 31.03.03 11 0m 23s 4m 20s 07.04.03 12 0m 31s 6m 22s 14.04.03 5 0m 43s 3m 35s 21.04.03 11 0m 39s 7m 16s 28.04.03 4 0m 12s 0m 49s 05.05.03 5 0m 40s 3m 21s 12.05.03 2 0m 27s 0m 55s 19.05.03 10 0m 24s 4m 2s 26.05.03 5 0m 21s 1m 47s 02.06.03 6 0m 31s 3m 8s 09.06.03 3 0m 21s 1m 5s 16.06.03 10 0m 30s 5m 6s 23.06.03 11 0m 24s 4m 33s
Phocine Distemper Virus Epizootic Investigation 2002/2003 6 • Appendix 5.5 – Example of UK PDV Status Report
Information on Phocine Distemper Virus in the UK 19th December
Between 11 December and 17 December there have been 47 dead seals reported around the UK bringing the total to 3682 since the beginning of the outbreak (see Figure 1 for country breakdown and Table 1 for species breakdown).
Figure 1: Cumulative total of dead seal reports from the UK.
Cumulative total of dead seal reports from the UK
d a e
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C 1 3 5 7 9 1 3 5 7 k k k k k 1 1 1 1 e e e e e k k k k NORTHERN e e e e e e e e e W W W W W e e e e IRELAND W W W W Week of epidemic (start 14.08.02)
Table 1: Breakdown of the number of reported dead seals of each species.
England Scotland Wales Northern UK Total Ireland Common Seals 290 84 0 48 422 Grey Seals 82 375 148 18 623 Indeterminate 2363 250 2 22 2637 Total 2735 709 150 88 3682
England: In the last week there have been 16 dead seals reported from the English coast bringing the total to 2735. The number of dead seal reports has continued to decline ever since the peak of the epidemic in mid-September and now appears to be virtually over in England (see Figure 2). 41 cases have been confirmed as positive for PDV (40 common and 1 grey) and 10 cases have been confirmed as negative for PDV (see Figure 3 for regional breakdown).
Figure 2: Weekly total of dead seal reports from the UK.
Weekly total of dead seal reports from the UK
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W 1 3 5 7 9 1 3 5 7 k k k k k 1 1 1 1 e e e e e k k k k NORTHERN e e e e e e e e e W W W W W e e e e IRELAND W W W W Week of epidemic (start 14.08.02)
Phocine Distemper Virus Epizootic Investigation 2002/2003 7
Figure 3: Regional breakdown of dead seals and positive PDV cases in England
Scotland: In the last week there have been 28 dead seals (20 grey seals, 1 common seal and 7 species indeterminate) reported from around Scotland bringing the total to 709. Post-mortem examinations have been carried out on 73 animals (31 common seals and 42 grey seals). 24 cases have been confirmed as positive for PDV (11 common seals and 13 grey seals), 18 cases have been confirmed as negative for PDV and test results from the remaining are pending (see Figure 4 for regional breakdown). In most areas around Scotland natural mortality of grey seal pups still appears to be in accordance with the seasonal increase in mortality associated with the pupping season.
Figure 4: Regional breakdown of dead seals and positive PDV cases in Scotland.
Wales: A total of 150 dead seals have been reported from around Wales, 18 post-mortem examinations have been carried out. 2 cases have been confirmed as negative for PDV and the results from the other 16 are pending (see Figure 5 for regional breakdown).
Phocine Distemper Virus Epizootic Investigation 2002/2003 8
Figure 5: Regional breakdown of dead seals in Wales.
Northern Ireland: A total of 88 dead seals have been reported from around Northern Ireland, 20 post-mortem examinations have been carried out (18 common seals, 2 grey seals), 2 cases have been confirmed as positive for PDV (2 common seals), 12 cases have been confirmed as negative for PDV and the results from the other 6 are pending (see Figure 6 for regional breakdown).
Figure 6: Regional breakdown of dead seals and positive PDV cases in Northern Ireland.
Phocine Distemper Virus Epizootic Investigation 2002/2003 9 • Appendix 6 - Images
Figure 1 Note the three cusps in each post- Figure 2 Note the single prominent cusp in canine tooth characteristic of a common seal the post-canine teeth characteristic of a grey (Phoca vitulina). seal (Halichoerus grypus).
Figure 3 Pile of seal carcasses for post mortem examination at temporary cold store Figure 4 Common seal for post facility. mortem examination at the Institute of Zoology, London.
Figure 5 Marked subcutaneous emphysema Figure 6 Conjunctival hyperaemia in a giving a “hump-backed” appearance to a common seal with phocine distemper. common seal with phocine distemper.
Phocine Distemper Virus Epizootic Investigation 2002/2003 1 Figure 7 Bloody nasal discharge in a Figure 8 Severe hard palate ulceration in a common seal with phocine distemper. common seal with phocine distemper.
Figure 9 Marked mediastinal, pericardial Figure 10 Mucopurulent contents within and pulmonary interlobular emphysema in a the tracheal lumen of a common seal with common seal with phocine distemper. phocine distemper.
Figure 11 Note the presence of Figure 12 Positive immuno-peroxidase intracytoplasmic and intranuclear inclusion staining for morbillivirus in the brain of a bodies in the brain, characteristic of common seal. morbilliviral infection in a common seal.
Phocine Distemper Virus Epizootic Investigation 2002/2003 2 Appendix 7
Systematic Reporting of Dead Seals
This section includes a detailed appraisal of each stage of the volunteer appeal and survey response, emphasising lessons learned through the process. This is intended to provide a guide for the future should volunteer schemes be considered for the investigation of a wildlife disease outbreak in the UK.
First date of contact from “potential” volunteers
The date of first contact from “potential” volunteers was examined to give an indication of the speed and timing of the response to the three stages of the appeal process. A “potential” volunteer is an individual who made contact expressing an interest in participating in the volunteer scheme following the appeal.
• Phase 1 Volunteer appeal – 15/08/02 – 21/08/02 Contact marine and key related organisations • Phase 2 volunteer appeal – 09/09/02 – 16/09/02 Contact wildlife organisations • Phase 3 volunteer appeal – 25/09/02 ZSL Press release to general public
For England a total number of 152 individuals contacted the Institute of Zoology as “potential” volunteers. The peak response occurred during late September, approximately 4-5 weeks after the investigation was launched, with a modal date of 26th September 2002. For Wales a total number of 14 individuals contacted Marine Environmental Monitoring as “potential” volunteers. The peak response occurred during early October 2002. No data is available for the initial date of contact of the Scottish volunteer network.
In retrospect, the peak of the PDV epizootic occurred in mid September 2002 and so the bulk of the volunteer team were not recruited until after this point. Individuals who responded to the appeal in the early stages were often those involved with animal rescue organisations (e.g. BDMLR) or land wardens. However the total number of respondents to phases one and two of the appeal were insufficient to provide the anticipated range of coastal coverage therefore the decision was made to appeal to the general public for assistance. The peak response to the targeted press release from the public occurred after a short lag period and this method proved effective for rapidly contacting larger numbers of individuals. The national co-ordinators noted variable regional attitudes and concern regarding the PDV epizootic that also affected the success of volunteer recruitment. The small number of volunteers recruited in Wales is probably due to the fact that PDV was not confirmed in the area and had not affected the grey seal population in 1988. There are no large common seal colonies in Wales.
Geographical distribution of “potential” volunteers
The geographical distribution of “potential” volunteers was examined as an indication of the spread of the response to the appeal. The 152 “potential” volunteer contacts for
Phocine Distemper Virus Epizootic Investigation 2002/2003 1 England came from a wide range of geographical regions. Approximately 28% of “potential” volunteers came from The Wash region (i.e. Norfolk and Lincolnshire) and 15% from Cornwall. In Scotland, a stronger response to the volunteer appeal was experienced on the east than west coast of Scotland despite the populations of seals being greater in the latter. In Wales, volunteers came from a fairly wide area of coast although half were from Gwynedd.
Success of Methods for publicising the volunteer appeal
Where possible, information was collated on the medium through which “potential” volunteers first heard of the appeal for assistance. This was examined to enable optimal targeting of advertising resources for future appeals.
Table 1: Routes through which volunteers heard of the appeal (England)
Method Number of volunteers BDMLR 36 Local Press 36 Radio/ TV 2 Wildlife Organisation 17 Internet 3 Multiple sources 6 Unknown and miscellaneous 52 Total 152
In England, the response to the appeal from British Divers Marine Life Rescue members was particularly significant. This organisation has a national network of motivated volunteers trained in marine mammal rescue techniques coupled with an efficient means of rapidly distributing appeals for assistance through member e-mail list serves. Whilst the appeal to wildlife organisations did not generate a large number of contacts, the recruited volunteers were often particularly committed and knowledgeable making this route of appeal worthwhile. Where available it was preferable for organisations to advertise the appeal on their websites since the delay for inclusion of material within magazine distributions was often considerable. Members of the public responded well to local press appeals targeting coastal areas, particularly in Norfolk and Cornwall.
In Scotland, a significant proportion of volunteers were approached to participate in the scheme after they had reported a dead seal or cetacean and were directed to SAC Inverness from local councils, Scottish SPCA offices and related organisations. Response to radio interview appeal was positive in Orkney. Within Wales, an established network of volunteers already exists as part of the “Collaborative UK Marine Mammal and Turtle Strandings Project”. In addition, Welsh volunteers were recruited through a variety of local organisations.
Proportion of “potential” volunteers who became “active” volunteers
The proportion of individuals that made contact as “potential” volunteers who went on to participate with survey reports (“active” volunteers) was studied. This provided
Phocine Distemper Virus Epizootic Investigation 2002/2003 2 an indication of the degree of continued interest in the volunteer scheme once details of the guidelines had been received.
Of the 152 “potential” volunteer contacts for England, approximately half reported at least one survey result. Of the 79 “potential” volunteer contacts that gave no report, approximately 28% of these were requested not to participate in the scheme due to the late date or risk of duplication in their nominated survey area. Stated reasons for deciding not to participate in the scheme included time commitments, ill health, travel abroad, moving job or home and risk of transmission to dogs. Similarly, in Wales half of the 14 “potential” volunteer contacts continued to report at least one survey result.
Date of first survey by active volunteers
The date of the first survey from active volunteers was examined to give an indication of the observed lag before obtaining results following the appeal. In England, Scotland and Wales the majority of first survey reports were received during early and late October 2002 (see Figures 1-3), after the peak of the PDV epizootic in the UK.
Fig. 1: Date of first survey by active volunteers (England) s
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Key: LA= Late August (16/08/02 – 31/08/02) ES= Early September (01/09/02 – 30/09/02)
Fig. 2: Date of first survey by active volunteers (Scotland) s
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N 0 LA ES LS EO LO EN LN ED LD Period of month
Key: LA= Late August (16/08/02 – 31/08/02) ES= Early September (01/09/02 – 30/09/02)
Phocine Distemper Virus Epizootic Investigation 2002/2003 3 Fig. 3: Date of first survey by active volunteers (Wales) s
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N 0 EA LA ES LS EO LO EN LN ED LD Period of month
Key: LA= Late August (16/08/02 – 31/08/02) ES= Early September (01/09/02 – 30/09/02)
Number of surveys sent per volunteer
The number of surveys sent per active volunteer was examined as an indication of volunteer effort. The “number of surveys” refers to the number of days on which a volunteer reported a survey result.
In England, volunteers contributed a wide range in the number of surveys (1-20 per individual) as illustrated in Figure 4. This demonstrated considerable variation in the length of time that volunteers continued participating in the scheme.
Fig. 4: Number of survey results per active volunteer (England)
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l 5 u o v N 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Number of surveys
In Scotland many active volunteers opted to send results on a daily basis and therefore the number of reports per volunteer is not easily comparable. In Wales a small number of volunteers were very committed, contributing regular surveys throughout the entire investigation period. The remainder of volunteers reported a small number of survey reports only (<4 reports per individual).
Duration of active period of surveys
The duration of the period of active surveys refers to the number of days between the first and last survey report for each volunteer. This data was examined as a second indication of volunteer effort. The period from the beginning of the volunteer appeal to the close of surveys was 114 days (15/08/02 – 06/12/02), 188 days (15/08/02 –
Phocine Distemper Virus Epizootic Investigation 2002/2003 4 21/03/03) and 152 days (15/08/02 – 13/02/03) for England, Scotland and Wales respectively.
In England and Scotland, volunteers were active for a wide range of periods throughout the investigation. However, the number of individuals who contributed throughout the entire duration of the study period was small (see Figures 5-6).
Fig. 5: Duration of active period of volunteer reports (England) s
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0 0 9 8 7 6 1 5 4 3 2 0 1 1 1
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1 1 1 1 1 1 1 1 1 1 1 8 7 6 5 4 3 2 1 Number of days between first and last report
Fig. 6: Duration of active period of volunteer reports (Scotland) s r
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------1 1 1 1 1 1 1 1 1 1 2 3 4 5 6 7 8 1 1 1 1 1 1 1 1 9 0 1 2 3 4 5 6 1 1 1 1 1 1 1 Number of days between first and last report
In Wales, the small group of active volunteers was active for extended periods of time (30-150 days).
Proportion of active volunteers who saw dead seals
The proportion of volunteers who saw dead seals during their surveys was examined as an indication of the results output from the scheme. The number of dead seals seen per volunteer was calculated as a guide to the information retrieved per active volunteer. Approximately half of active volunteers saw at least one dead seal during their surveys with values of 47% (N=29), 45% (N=29) and 43% (N=3) for England, Scotland and Wales respectively. The majority of individuals saw less than five dead seals in total during all of their surveys as illustrated in Figures 7-9. The total number of dead seals observed by the entire volunteer network was 128, 231 and 10 carcasses for England, Scotland and Wales respectively.
Phocine Distemper Virus Epizootic Investigation 2002/2003 5
Fig. 7: Number of dead seals seen by active volunteers (England)
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u 5 N 0 0 1 - 5 6 - 10 11 - 20 21 - 30 31 - 40 41 - 50 51 - 60 61 - 70 Number of dead seals seen per volunteer
Fig. 8: Number of dead seals seen by active volunteers (Scotland)
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N 0 0 1 - 5 6 - 10 11 - 20 21 - 30 31 - 40 41 - 50 51 - 60 61 - 70 Number of dead seals seen per volunteer
Fig. 9: Number of dead seals seen by active volunteers (Wales)
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N 0 0 1 - 5 6 - 10 11 - 20 21 - 30 31 - 40 41 - 50 51 - 60 61 - 70 Number of dead seals seen per volunteer
Information on species identification
Information on species identification from volunteer reports was examined as a measure of information quality collected through the scheme.
Phocine Distemper Virus Epizootic Investigation 2002/2003 6
In England, approximately 80% of volunteers who saw dead seals identified the species of at least one carcass; approximately 60% of seals seen by volunteers were identified to species level. Of dead seals identified to species level, 82% were common seals and 18% were grey seals (see Table 2). Of carcasses identified to species level from The Wash (Norfolk and Lincolnshire), 94% were common and 6% grey seals.
Table 2: Number and species of dead seals reported by volunteers (England)
Species Total number of dead seals seen by active volunteers Phoca vitulina 61 Halichoerus grypus 13 Unidentified 54 Total 128
In Scotland, approximately 83% of volunteers who saw dead seals identified the species of at least one carcass; approximately 85% of seals seen by volunteers were identified to species level. Of dead seals identified to species level, 93% were grey seals and 7% were common seals (see Table 3).
Table 3: Number and species of dead seals reported by volunteers (Scotland)
Species Total number of dead seals seen by active volunteers Phoca vitulina 14 Halichoerus grypus 183 Unidentified 34 Total 231
In Wales, all volunteers gave information on species identification and all seals seen by volunteers were identified to species. The situation in Wales is markedly different to that in England and Wales where the seal population is almost entirely grey, apart from rare exceptions in the north.
Table 4: Number and species of dead seals reported by volunteers (Wales)
Species Total number of dead seals seen by active volunteers Phoca vitulina 0 Halichoerus grypus 10 Unidentified 0 Total 10
Information on body length measurements
Phocine Distemper Virus Epizootic Investigation 2002/2003 7 Information on body length measurements from volunteer reports was examined as a second measure of the detail of information collected through the scheme.
In England, approximately 70% of active volunteers gave an exact body length measurement on at least one carcass and over 90% gave some information on the estimated size or age of the seal. In Scotland, approximately 83% of active volunteers gave an exact body length measurement and almost 95% gave some information on the estimated size or age of the seal. None of the Welsh volunteers gave exact information on body length measurements although approximately half gave some details of estimated size or age of the seal.
Methods for communicating survey results
Email communication proved the most efficient and popular method for reporting of survey results. The majority of active volunteers reported their survey results electronically (73% of English volunteers). Volunteers tended to use the pro forma Microsoft ExcelTM template for reporting surveys where dead seals had been observed. “Negative” sightings report data were frequently included as text within an email.
In England, relatively small numbers of active volunteers reported their results by telephone, fax and post (15 %, 8% and 1% respectively). In addition, Scottish volunteers were sent a hard copy reporting template and a number of pre-paid envelopes to return completed survey forms.
Phocine Distemper Virus Epizootic Investigation 2002/2003 8