Proliferative leg skin lesions have been described in wild finches in Europe although there have been no large-scale studies of their aetiology or epizootiology to date. Firstly, disease surveillance, utilising public reporting of observations of live wild finches was conducted in Great Britain (GB) and showed proliferative leg skin lesions in chaffinches (Fringilla coelebs) to be widespread. Seasonal variation was observed, with a peak during the winter months. Secondly, pathological investigations were performed on a sample of 39 chaffinches, four bullfinches (Pyrrhula pyrrhula), one greenfinch (Chloris chloris) and one goldfinch (Carduelis carduelis) with proliferative leg skin lesions and detected Cnemidocoptes sp. mites in 91% (41/45) of affected finches and from all species examined. Fringilla coelebs papillomavirus (FcPV1) PCR was positive in 74% (23/31) of birds tested: a 394 base pair sequence was derived from 20 of
these birds, from all examined species, with 100% identity to reference genomes. Both mites and FcPV1 DNA were detected in 71% (20/28) of birds tested for both pathogens. Histopathological examination of lesions did not discriminate the relative importance of mite or FcPV1 infection as their cause. Development of techniques to localise FcPV1 within lesions is required to elucidate the pathological significance of FcPV1 DNA detection.We thank the members of the public and BTO Garden BirdWatch participants who reported garden bird morbidity and mortality incidents and our colleagues, Katie Beckmann, Shaheed Macgregor, Ricardo Castro Cesar de Sa, Lydia Franklinos and Tim Hopkins from the Zoological Society of London; Kirsi Peck from the Royal Society for the Protection of Birds; BTO staff members in the Garden BirdWatch team; the staff at Abbey Veterinary Services and the Animal & Plant Health Agency (Daniel Hicks, Richard Irvine, Alejandro Núñez and Scott Reid) for their assistance with this investigation. This work was financially supported by the following organisations; Birdcare Standards Association, British Trust for Ornithology, British Veterinary Association Animal Welfare Foundation, CJ Wildbird Foods, Cranswick Pet Products, UK Department for the Environment Food & Rural Affairs and Welsh Government through the Animal & Plant Health Agency’s Diseases of Wildlife Scheme Scanning Surveillance Programme (Project ED1600), Esmée Fairbairn Foundation, Gardman Ltd,
Institute of Zoology, Royal Society for the Protection of Birds and the Universities Federation for Animal Welfare. RAJW was supported by the Moncloa of Excellence PICATA programme and Crafoord Foundation Sweden (grant number 20160971). Molecular and sequencing costs were funded by the Spanish Ministry of Science and Innovation, (Ref: CGL2013-41642-P/BOS)
