Psittacine beak and feather disease in a free-living ring-necked parakeet (Psittacula krameri) in Great Britain

The ring-necked parakeet (RNP), Psittacula krameri, is an invasive species in Great Britain (GB) which is undergoing rapid population expansion in the wild. Although it has been suggested that RNPs could be a potential source of infectious disease, little research has been done on the pathogens infecting this species in GB. Psittacine beak and feather disease (PBFD), caused by beak and feather disease virus (BFDV), is an important infectious disease of psittacines, including captive RNPs, in GB and elsewhere. A wild RNP with marked feather abnormalities observed in an urban garden in London was euthanased and examined post mortem. Plucked contour feathers and pooled liver and spleen were PCR-positive for BFDV DNA. Histopathological examination of affected skin demonstrated BFDV-compatible lesions. A feather from another RNP from a different location also was PCR-positive for BFDV. This is the first report of PBFD in a wild free-living bird in GB. BFDV only affects psittacines; therefore, there is no known risk to native British birds. The presence of BFDV in free-living RNPs, however, could pose a disease threat to captive psittacines. Further work is required to determine the distribution and impact of BFDV infection in free-living RNPs in GB. Whether this case represents sporadic disease associated with established endemic infection or the index case of an emergent disease is currently unknown.