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Wildlife disease surveillance

Wildlife surveillance is an important part Alongside MPI’s wildlife activities, causes laboratories and researchers. Figure 1 of ’s national surveillance of mortalities of threatened or critically shows numbers of avian cases compared system for exotic and emerging pests endangered native are monitored to numbers of cases involving other and disease. The purpose of the Ministry by the Department of Conservation types of wildlife from 2012 to 2016. The for Primary Industries (MPI)’s wildlife (DOC), as part of a DOC contract number of avian cases submitted in 2016 surveillance programme is to: undertaken by Wildbase Pathology (part decreased slightly compared to 2015 and • facilitate early detection of exotic and of the Institute of Veterinary, comprised 88 percent of all submissions, emerging diseases; and Biomedical Sciences, or IVABS, at with native lizards (skinks and geckos) Massey University, Palmerston North). 4 percent, tuatara (Sphenodon spp.) • support New Zealand’s statements Certain found dead in the field 2 percent, cetaceans (whales and Hector’s of freedom from specific pests and or in captive facilities are sent to the dolphins, Cephalorhynchus hectori) diseases; laboratory for post-mortem examination 1 percent, pinnipeds (mainly NZ sea • provide baseline information on by veterinary wildlife pathologists lions, Phocarctos hookeri) 1 percent, endemic disease occurrence in and the results held in the amphibians 1 percent, and native fish and New Zealand wildlife; and database at IVABS. bats < 1 percent. Other wild mammals • support fulfilment of New Zealand’s (mustelids and ) totalled just Details of wildlife cases held in the Huia international reporting obligations. over 2 percent. wildlife disease database and investigated The MPI national exotic pest and disease by MPI disease investigators over the Mortalities of both juvenile and notification system provides for the previous year are discussed below. adult yellow-eyed penguins or hōiho reporting and investigation of unusual (Megadyptes antipodes) continued to be disease events in all animals, including Wildlife cases processed by of concern in the coastal Otago region. wildlife. The MPI pest and disease veterinary laboratories Predation by mustelids and dogs was the emergency hotline (0800 80 99 66) helps Records of wildlife mortality are held in main cause of mortalities of kiwi (Apteryx New Zealanders to meet their obligations the Massey Pathology and Huia wildlife spp.). Mustelid predation of blue under section 44 of the Biosecurity disease databases, jointly owned by DOC or whio (Hymenolaimus malacorhynchos) Act 1993, which requires every person and Massey University and maintained occurred in several areas during re- to report to MPI any suspected cases by Wildbase Pathology at IVABS. Most introduction programmes. There was caused by organisms not normally seen cases involve mortalities in indigenous an increase in the number of lizard or otherwise detected in New Zealand. , in particular threatened species and tuatara necropsies performed and This enables the appropriate investigation submitted by DOC for diagnosis by a moderate decrease in the number of suspected cases of exotic or emerging Wildbase Pathology. These databases of marine mammal, native fish and diseases that are identified in wildlife also hold some case records from bat necropsies. by organisations or individuals working surveillance activities, private veterinary outside of MPI surveillance programmes. In addition to investigating reported events, MPI undertakes annual active surveillance in wild birds for avian influenza viruses (see Avian influenza surveillance programme report, page 18) and monitoring of routine disease diagnoses by veterinary diagnostic laboratories to detect possible indications of occurrence that may indicate an emerging disease requiring further investigation. MPI receives anonymised commercial laboratory summaries from feral animals, captive animals and wild native animals meeting a sick animal case criterion. Reports of particular interest are summarised in the quarterly articles reviewing diagnostic cases in each edition of Surveillance. Figure 1: Numbers of wildlife cases in birds and other taxonomic groups recorded in the Massey Pathology and Huia Wildlife Disease databases, 2012–2016

SURVEILLANCE 44 (3) 2017 21 Disease surveillance of highly threatened species such as (Strigops habroptila), (Himantopus novaezelandiae), hihi/ (Notiomystis cincta) and the and subspecies of kiwi, continued throughout the year. A small number of wild introduced birds were examined because of the interest in preventing transmission of diseases such as malaria, beak-and-feather disease and salmonellosis from introduced birds to native species. The geographic distribution of avian wildlife cases examined in 2016 is shown in Figure 2. The highest numbers of cases submitted were from the Manawatu/ Whanganui, and Otago regions. Cases from the Manawatu/ Whanganui region included those from the National Wildlife Centre at Mt Bruce/ Pukaha, and . The Wellington submissions included those from Wellington Zoo, Zealandia, Mana Island, and the Chatham Islands. Otago submissions included those from the highly endangered population of yellow-eyed penguins of coastal Otago. cases included those from Otorohanga, Mangatautari and Hamilton Zoo. The Canterbury region contains Mt Cook National Park as well as captive breeding centres for threatened species at Twizel, Willowbank and Peacock Springs. Many cases submitted from the Auckland Figure 2: Number of avian cases submitted to Wildbase Pathology in 2016 by region region were of threatened species from offshore islands including Tiritiri Matangi, Motutapu and Ponui. Moderate while certain other species including sampled in 2012, but in several instances numbers of cases were submitted hihi (Notiomystis cincta), the levels were high (Glare et al., 2014). directly from locally administered ( spp.) and shore plover However, since 2013, no aspergillosis wildlife sanctuaries, including Bushy (Thinornis novaeseelandiae) are more cases have been recorded in kiwi. consistently affected Figure( 3). Park, Mangatautari, Cape Kidnappers In yellow-eyed penguins, however, and Zealandia. Until recently, kiwi held in captive numerous cases of aspergillosis have facilities have been prominent among been seen during the last 3 years. The Wildlife cases of special aspergillosis cases, with 17 cases reported birds affected have been mainly adults interest in 2016 between 1997 and 2011. Most of the brought into care after leg and flipper Respiratory aspergillosis in affected birds were held in enclosures injuries (Hunter et al., 2016). These endangered native birds with a soil base that was usually planted birds were clearly stressed, initially Respiratory aspergillosis continues to be with native vegetation and contained from trauma in the wild, then from a common cause of mortality in endemic leaf litter brought in to provide ground treatment and handling in their captive New Zealand birds. The numbers of cover and encourage foraging. Low environment; some were also infected some species affected ( e.g., kiwi and levels of Aspergillus fumigatus spores with avian malaria. penguins) varies markedly between years, were detected in almost all kiwi houses

22 SURVEILLANCE 44 (3) 2017 a survey of Wellington Histopathology of samples of abnormal residents whose gardens bone showed variable thinning of cortical were visited by kaka bone, but most of the trabecular bone in 2012, 22 percent spicules, and the endosteal surface of admitted to feeding the cortical bone, were covered in thick common household osteoid in often disorganised seams foods to the wild birds containing plump osteocytes. There (Linklater, 2016). was an increase in both osteoblast and osteoclast activity in the marrow, The natural diet of kaka particularly around the primary consists of fruit, nectar, spongiosa, and replacement by abundant and sap loose connective tissue. There were often Figure 3: Cases of respiratory aspergillosis in some endangered birds obtained by removing several small islands of hypertrophied necropsied at Wildbase Pathology, 2013–2016 bark from trees, and the chondrocytes bordered by both birds’ nutritional status mineralised bone and osteoid within the The recurring aspergillosis mortalities is likely to be a limiting primary spongiosa. seen in hihi, kakariki and shore plover factor in their reproductive success have occurred in both free-living (Beggs & Wilson, 1991). In an urban birds and birds held in large, open setting, exotic trees such as conifers and and well-ventilated enclosures that eucalypts are significantly more likely to would seem unlikely to harbour high be damaged than native trees (Charles numbers of fungal spores. This suggests & Linklater, 2014). Kaka chicks spend that these species are particularly a long period (more than 10 weeks) in vulnerable to infection, possibly owing the nest before fledging, and during this to immunosuppression caused by time they are completely reliant on food environmental or nutritional stress. obtained by their parents. There is also the possibility that some of The affected kaka (seeTable 1, page 24) these endangered species may possess were all juveniles or fledglings and were decreased immunocompetence through observed to be in poor body condition. having experienced a breeding bottleneck They displayed a variety of beak and limb during translocation or captive rearing. deformities. Some showed weakness, Metabolic bone disease in kaka abnormal stance, difficulty in walking from urban Wellington and had broken feather shafts on the The Zealandia wildlife sanctuary wings and tail. Some had severe limb now provides an overflow of birds, deformities and multiple limb fractures, Figure 4: An affected juvenile kaka showing a necessitating euthanasia. One affected “scissor beak” deformity. Photograph by Stuart particularly kaka ( meridionalis Hunter septentrionalis), into the surrounding chick was found dead in its nest, and parks and residential gardens of another on a walkway. Radiographs of Wellington. Many city gardens have the affected birds showed a range of The re-introduction of kaka to proven to be rich in natural foods and lesions, including poor bone density, Wellington does have the potential to nesting cavities, and most local residents bowing of long bones, folding and other provoke a human/wildlife conflict, as greatly enjoy the presence of the birds in fractures of long bones, excessive spinal pointed out recently by Linklater (2016), their gardens. Unfortunately this has led curvature, and malformed synsacrums who suggested that kaka should be to the feeding of birds with unsuitable and sternums. removed, or at least reduced in numbers, foods such as cheese, nuts and various On gross post-mortem examination from Wellington city gardens mainly grains including corn and maize. Many many of the birds had beak deformities, because of the damage they do to exotic of these common foodstuffs have a with softening of the premaxillae and trees. This opinion provoked an outcry ratio of phosphorus to calcium that is mandibles, which were easily bent from many Wellingtonians, 80 percent too high for rapidly growing birds – for (Figure 4). Many long bones were of whom are reported to enjoy having example corn 25:1 and cashew nuts affected, particularly the tibiotarsi, the birds around their homes (Linklater, 16:1, when the ideal ratio is about 1:2 which were often rotated or deviated and 2016). However, the development (Roudybush, 1997). Such feeding may malleable to digital pressure. Folding of metabolic bone disease in kaka cause hypocalcaemia and osteoclastic fractures, sometimes multiple, were indicates that Wellingtonians should be bone resorption followed by replacement also seen in many long bones. These discouraged from providing artificial of bone with fibrous connective tissue. In abnormalities are summarised in Table 1. foods for the birds.

SURVEILLANCE 44 (3) 2017 23 Tuberculosis in wild birds and Hector’s dolphin that was found dead Wildbase Pathology for post-mortem marine mammals near Kaikoura. examination. No significant gross or Several cases of avian tuberculosis Wildlife cases notified via the MPI histological lesions were identified in any of the birds. The absence of have now been seen in Australasian exotic pest and disease hotline harriers (Circus approximans) in haemorrhage or inflammatory lesions Exotic causes of disease were ruled out in New Zealand. The mycobacteria have in major organs excluded exotic viral all wildlife investigations conducted by caused granulomatous lesions in the feet diseases. Botulism was suspected because MPI in the past year. (Hunter & Alley, 2014) and in the oral of the clinical presentation, season cavity (Alley et al., 2004). In 2016, a wild MPI investigates cases of mass mortality (very low recent rainfall associated harrier from Canterbury was seen to lose in wild birds, and this year several such with an El Nino summer) and locality weight and died soon after arrival at the events were reported. In one case, a (the Firth of Thames has previously vet clinic. At necropsy it was found to DOC ranger in the Firth of Thames experienced similar large-scale botulism have numerous granulomatous lesions reported paralysis affecting a variety events). Botulism is a difficult disease in the lungs, liver and mesentery, which of wild birds over about 3 weeks in to confirm, and testing for Clostridium contained many intralesional acid-fast- late January and early February. The botulinum toxin genes by PCR failed staining rods. The route of infection in syndrome included progressive paralysis to detect the agent. Direct toxin testing this case could not be determined but it of the hind limbs, spreading to involve was unavailable, which would have the head and neck and resulting in death. been more biologically sensitive, but nevertheless botulism was considered the TABLE 1: Cases of metabolic bone disease in kaka confirmed by post-mortem most likely cause of this outbreak. examination at Wildbase Pathology, 2008–2016 In April, an outbreak of suspected Year Month Age of bird Lesions No examined toxicity in captive ducks was reported from a Gisborne lifestyle block. On the 1 2008 January Neonate Unstable tarsal joints. Healed tibiotarsal fractures. first day, one died, followed by six 2 December Juvenile Severe generalised fibrous osteodystrophy. the next day. Clinical signs included 3 2011 December 3–5 weeks Splayed legs. Rotational (tibiotarsal) deformities. flaccidity followed by death. The farm 4 December 3–5 weeks Splayed legs. Rotated legs. Dislocated stifle(s). veterinarian noted that the feed bag 5 2013 December 3–4 weeks Osteopenia. Folding fractures in multiple bones. was almost empty, and suggested a 6 December Juvenile Generalised limb deformities. change of feed and frequent changing 7 2015 November Juvenile "Scissor beak" deformity. of water dishes. Unfortunately, no 8 December Juvenile Severe generalised limb deformities. samples were available at the time of 9 December Juvenile Severe generalised limb deformities. notification. No further ducks became ill, 10 2016 January Fledgling Malleable bones. Rotational limb deformities. so epidemiologically this was considered 11 January Fledgling Malleable long bones. "Scissor beak" deformity. to be a toxic point exposure such as botulism or aflatoxicosis, rather than a propagating disease. is assumed to be from eating the infected The birds remained alert and continued Three suspected cases of Pacheco’s carcasses of backyard poultry, wild to eat before developing the final stages disease (psittacine herpesvirus) were game birds and other birds. Advanced of paralysis. Although predominantly reported and ruled out during the year. avian tuberculosis was also found in waterfowl (mallards and paradise ducks) In one, three juvenile had been an aged pukeko (Porphyrio melanotus) were killed, a number of shorebirds bought recently and two had become ill, that was kept in captivity with two were also affected, predominantly with one dying. Histology on the liver of (Gallirallus australis), both of which had ruddy turnstones (Arenaria interpres), the dead bird found multifocal necrosis intestinal avian tuberculosis. red knots (Calidris canutus), banded with intranuclear inclusion bodies. dotterels (Charadrius bicinctus), pied Two further cases of tuberculosis were Polyomavirus PCR testing had already oystercatchers (Haematopus ostralegus) seen in New Zealand sea lions from the been conducted and was negative. and black-backed gulls (Larus Otago coast during 2016. The lesions DNA from blood samples was available dominicanus). Eight birds showed clinical seen were similar to previous cases of from the two live parrots, and fixed disease: three mallard ducks, (Anas tuberculosis seen in and liver from the dead one, but Pacheco’s platyrhynchos), a paradise Auckland Islands marine mammals and disease PCR was negative for all three. (Tadorna variegata), a red knot, a are caused by Mycobacterium pinnipedi PCR for adenovirus, for which hepatic banded dotterell, a (Anarhynchus (Cousins et al., 2003; Duignan, 2003). intranuclear inclusion bodies are also frontalis) and a godwit (Limosa This same organism was also responsible characteristic, was positive on the liver lapponica). These were submitted to for tuberculous granulomas found in a sample. The DNA product was sequenced

24 SURVEILLANCE 44 (3) 2017 to psittacine adenovirus 1. A number of lesions in wild game. In June a case urban landscape. Emu 114(4), 317–325. avian adenoviruses of fowl are endemic of suspected hydatidosis in a feral Cousins DV, Bastida R, Cataldi A, Quse V, in New Zealand poultry, and a serological was reported by a pig hunter from Redrobe S, Dow S, Duignan P, Murray A, survey of pigeons in New Zealand found Northland. Hydatid disease, caused by Dupont C, Ahmed N, Collins DM, Butler WR, that positive titres were common in all Echinococcus granulosus, is exotic to Dawson D, Rodrígue D, Loureiro J, Romano MI, the areas sampled (Black et al 2004). New Zealand, having been eradicated. Alito A, Zumarraga M, Bernardelli A (2003). Tuberculosis in seals caused by a novel member There have also been suspect cases of Another exotic cause of cysts can be the of the Mycobacterium tuberculosis complex: adenovirus in parrots, including a 2010 tapeworm Cysticercus cellulosae/Taenia Mycobacterium pinnipedii sp. nov. International MAF Biosecurity New Zealand exotic solium. Endemic causes of the lesions Journal of Systematic Evolutionary Biology 53, disease investigation into an African include parasitism (e.g., from migrating 1305–1314. grey (Psittacus erithacus) with a roundworms such as Ascaris suis) and Duignan PJ (2003). Disease investigations in positive psittacine adenovirus PCR result tuberculosis. During sampling it was stranded marine mammals, 1999–2002. DOC and consistent histopathology. However, noted that the liver contained about Internal Science Series, 1–32. the present investigation appears to 20 solid to cystic pale nodules 1–3 cm Glare TR, Gartrell BD, Brookes JJ, Perrot JK be the first characterisation through in length scattered throughout the (2014). Isolation and Identification ofAspergillus sequencing of psittacine adenovirus in parenchyma. Culture of the frozen and spp. from Brown Kiwi (Apteryx mantelli) in parrots in New Zealand. In a second case, thawed samples yielded moderate mixed Nocturnal Houses in New Zealand. Avian a Derbyan parrot (Psittacula derbiana) bacterial growth that was considered Diseases 58(1), 16–24. had histological evidence of hepatitis insignificant. Histopathology showed that Hunter SA, Alley MR (2014). Cutaneous avian and splenitis, with inclusion bodies the lesions consisted of a predominantly tuberculosis in the feet of wild Harriers, Circus present. The bird had appeared healthy eosinophilic infiltrate containing approximans. Kokako 21(2), 60. before dying, and had no obvious cause occasional parasite sections consistent Linklater W (2016). Kaka conflict: Conservation of death at gross postmortem. PCR with larval trematodes (flukes). As part icon to pest. Dominion Post, http://www. tests at the IDC (Wallaceville) for the of the life cycle, young flukes migrate stuff.co.nz/environment/79817641/Kaka- exotic differentials Pacheco’s disease, through the liver parenchyma before conflict-conservation-icon-to-pest. Accessed 16th June 2017. avian polyomavirus and psittacine reaching the biliary tract, where they adenovirus were all negative. A third mature. It was considered most likely Roudybush TE (1997). Nutrition. In: Avian case, in November, involved an aviary that this was a case of normal parasite Medicine and Surgery Altman RB, Clubb SL, with hand-reared . Over a migration through the liver of this pig. Dorrestein SM, Quesenberry K (Editors), W.B. Saunders and Company, Philadelphia, p. 36. 3-week period 10 of 17 cockatoos aged References between 3 weeks and 3 months died. Alley MR, Coomer AR, Gartrell BD (2004). Five birds were submitted to a regional Maurice Alley Mycobacterial stomatitis and associated Wildbase Pathology laboratory. Hepatomegaly was a feature capillariasis in an Australasian harrier (Circus Institute of Veterinary, Animal and of gross postmortem, with necrotising approximans). Kokako 11(1), 3–5. hepatitis and intranuclear inclusion Biomedical Sciences Beernaert LAF, Pasmans F, Van Waeyenberghe Massey University bodies identified in hepatocytes on L, Haesebrouk F, Martel A (2010). Aspergillus Palmerston North histopathology. While the inclusion infections in birds: a review. Avian Pathology 39, bodies were probably due to an avian 325–331. [email protected] adenovirus, Pacheco’s disease is an exotic Beggs JR, Wilson PR (1991). The kaka Nestor Kelly Buckle differential for inclusion body hepatitis. meridionalis, a endangered Incursion Investigator Liver samples from necropsied birds and by introduced wasps and mammals. Biological Surveillance and Incursion Investigation cloacal swabs from in-contact birds were Conservation 56(1), 23–38. (Animal Health) submitted to the AHL, where PCR testing Bingham P (2010). Quarterly report of Diagnostic and Surveillance ruled out Pacheco’s disease. Further investigations of suspected exotic diseases. Services Directorate PCR testing confirmed the diagnosis of Surveillance 37(2), 43-49. Ministry for Primary Industries adenovirus, which sequencing identified Bingham P (2017). Quarterly report of [email protected] as psittacine adenovirus 1. Psittacine investigations of suspect exotic diseases. Toni Tana adenovirus, and more specifically Surveillance, 44 (1), 18–24. psittacine adenovirus 1, have previously Senior Adviser Black H, Stanislawek WL, Cooper C, Saunders Surveillance and Incursion Investigation been recorded in New Zealand (Bingham W (2004). Avian virus survey in pigeons. (Animal Health) 2010; Bingham 2017). Exotic disease was Surveillance 31(4), 20–21. ruled out and the investigation closed. Diagnostic and Surveillance Charles KE, Linklater WL (2014). Selection of Services Directorate trees for sap-foraging by a native New Zealand In addition to avian disease, MPI Ministry for Primary Industries parrot, the Kaka (Nestor meridionalis), in an receives notifications of unusual [email protected]

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