Kent Academic Repository Full text document (pdf) Citation for published version Fogell, Deborah J. and Martin, Rowan O. and Groombridge, Jim J. (2016) Beak and feather disease virus in wild and captive parrots: an analysis of geographic and taxonomic distribution and methodological trends. Archives of Virology . pp. 1-16. ISSN 0304-8608. DOI https://doi.org/10.1007/s00705-016-2871-2 Link to record in KAR http://kar.kent.ac.uk/56194/ Document Version Publisher pdf Copyright & reuse Content in the Kent Academic Repository is made available for research purposes. Unless otherwise stated all content is protected by copyright and in the absence of an open licence (eg Creative Commons), permissions for further reuse of content should be sought from the publisher, author or other copyright holder. Versions of research The version in the Kent Academic Repository may differ from the final published version. Users are advised to check http://kar.kent.ac.uk for the status of the paper. Users should always cite the published version of record. Enquiries For any further enquiries regarding the licence status of this document, please contact: [email protected] If you believe this document infringes copyright then please contact the KAR admin team with the take-down information provided at http://kar.kent.ac.uk/contact.html Arch Virol DOI 10.1007/s00705-016-2871-2 REVIEW Beak and feather disease virus in wild and captive parrots: an analysis of geographic and taxonomic distribution and methodological trends Deborah J. Fogell1 • Rowan O. Martin2,3 • Jim J. Groombridge1 Received: 9 January 2016 / Accepted: 24 April 2016 Ó The Author(s) 2016. This article is published with open access at Springerlink.com Abstract Psittacine beak and feather disease (PBFD) has of wild populations, particularly in view of the intrinsic emerged in recent years as a major threat to wild parrot connection between global trade in companion birds and populations and is an increasing concern to aviculturists the spread of novel BFDV strains into wild populations. and managers of captive populations. Pathological and Increased emphasis should be placed on the screening of serological tests for screening for the presence of beak and captive and wild parrot populations within their countries feather disease virus (BFDV) are a critical component of of origin across the Americas, Africa and Asia. efforts to manage the disease and of epidemiological studies. Since the disease was first reported in the mid- 1970s, screening for BFDV has been conducted in Introduction numerous wild and captive populations. However, at pre- sent, there is no current and readily accessible synthesis of Pathogens responsible for emerging infectious diseases screening efforts and their results. Here, we consolidate (EIDs) have become a major concern in conservation information collected from 83 PBFD- and BFDV-based biology owing to their potential for rapid evolution and the publications on the primary screening methods being used effect that an epidemic may have on vulnerable species [1]. and identify important knowledge gaps regarding potential Consequently, understanding infectious diseases and their global disease hotspots. We present trends in research management in wildlife populations has become increas- intensity in this field and critically discuss advances in ingly important to conservationists [2]. Assessing the screening techniques and their applications to both avi- prevalence and impact of disease can be challenging, par- culture and to the management of threatened wild popu- ticularly during the outbreak of a novel pathogen [3]. Data lations. Finally, we provide an overview of estimates of collected and used in these circumstances often vary in the BFDV prevalence in captive and wild flocks alongside a sampling or assessment method used, frequently with complete list of all psittacine species in which the virus has imperfect diagnostic tests providing the only available been confirmed. Our evaluation highlights the need for insight into infection incidence within a population [4, 5]. standardised diagnostic tests and more emphasis on studies Consequently, synthesising multiple sources of information across many species can provide insight into how to improve management of infectious disease, identify & Deborah J. Fogell knowledge gaps, and reveal where improvements in [email protected] surveillance methods might be required. Psittacine beak and feather disease (PBFD) has been 1 Durrell Institute of Conservation and Ecology, University of Kent, Canterbury CT2 7NZ, UK detected in both wild and captive parrot populations since the mid-1970s. The disease has been found to be widely 2 World Parrot Trust, Glanmor House, Hayle, Cornwall TR27 4HB, UK infectious and often fatal, affecting both Old and New World psittacine species. PBFD is thought to have been 3 Percy FitzPatrick Institute of African Ornithology, DST/NRF Centre of Excellence, University of Cape Town, Cape Town, first documented in the late 1880s in wild Australian South Africa Psephotus parrots and was described as feathering 123 D. J. Fogell et al. abnormalities that impaired their flight [6]. Most com- through contact with contaminated feather dust, surfaces or monly affecting immature and fledgling birds, classical objects [29], and it can also be passed directly from a symptoms include symmetrical loss of contour, tail and female to her offspring [10, 30]. The management of PBFD down feathers and subsequent replacement by dystrophic in captivity is economically important in some countries; and necrotic feathers that fail to grow soon after emergence for example, it was estimated that aviculturists in South from the follicle [7–9]. Beak deformities such as fractures, Africa lose up to 20 % of their flock to the disease annually abnormal elongation and palatine necrosis are also typical [31]. Worryingly, many wild populations of vulnerable symptoms of PBFD, but their presence and severity vary species are also affected, including the Cape parrot (Poi- from species to species [10]. Other clinical symptoms cephalus robustus) of South Africa [25], the Australian include lethargy, depression, diarrhoea and immunosup- orange-bellied parrot (Neophema chrysogaster)[28, 32] pression, which are individually variable, sometimes lead and swift parrot (Lathamus discolor)[33], and the Mauri- to death, and may depend on the virulence of the viral tius (or ‘‘echo’’) parakeet (Psittacula echo)[30]. Therefore, strain or the route of viral exposure [11]. understanding the mechanics behind the spread of BFDV Beak and feather disease virus (BFDV) is a member of and how to test for its prevalence has taken on a renewed the family Circoviridae [12], which includes the smallest global relevance. known autonomously replicating pathogenic animal viruses Concern over the implications for conservation, avicul- [13–15]. The first complete BFDV genome sequence con- ture and biosecurity together with methodological advan- firmed its relationship to other circoviruses [16]. The ces in the detection of the virus has prompted a recent structure of BFDV isolated from viral inclusion bodies was increase in research effort. The development of new determined to be a non-enveloped, icosahedral virion methodologies has provided the basis on which researchers between 14 and 16 nm in size and containing a single- are now able to model the potential routes of transmission stranded DNA genome approximately 1.7 to 2.0 kilobases around the world [34], link BFDV prevalence to manage- in length [10]. ment-related tools for endangered species recovery [35], Until the early 1990s, histology and recovery of virions and determine the ways in which anthropogenic activities were the primary means of determining whether a bird was have changed the way in which the virus is evolving due to infected with BFDV. The first haemagglutination (HA) and recombination [36]. Remarkably, whilst there are many haemagglutination inhibition (HI) assays were then devel- research teams worldwide working on BFDV and PBFD, oped as a technique for both the identification and quan- there is a severe lack of synthesised knowledge on the tification of virus recovered from BFDV-positive birds primary screening methods being used, the species affec- [17]. Since the initial description of the syndrome, several ted, and, consequently, potential disease hotspots that have attempts have been made to culture the virus in vitro in lacked attention. Here, we aim to consolidate the most order to provide a source of antigen for vaccinations, but pertinent patterns and methods emerging from the literature these have not yet been successful [16, 18, 19]. The lack of published since the first scientific description of PBFD in an effective vaccine has compelled researchers to develop 1984 to provide both a qualitative and quantitative over- techniques to further examine the molecular genetics of the view of approaches and screening results. Our review virus; encouraging development of oligonucleotide-probe- provides a much-needed source of information for use by based methodologies such as dot-blot DNA hybridization, conservation practitioners regarding BFDV prevalence DNA in situ hybridization, and a polymerase chain reaction estimates in captive and wild flocks. Our objective is not to (PCR)-based assay [20, 21]. Critically, as infection and the provide an exhaustive description of each technique, but presentation of clinical disease are fundamentally different instead to analyse the trends in how screening has