title: Mortality associated with avian reovirus infection in a free-living magpie (Pica pica) in Great Britain.
abstract: BACKGROUND
  Avian reoviruses (ARVs) cause a range of disease presentations in domestic, captive and free-living bird species. ARVs have been reported as a cause of significant disease and mortality in free-living corvid species in North America and continental Europe. Until this report, there have been no confirmed cases of ARV-associated disease in British wild birds.
  
  
  METHODS
  Sporadic individual magpie (Pica pica) mortality was detected at a single site in Buckinghamshire, England, April-September 2013. An adult female magpie was found moribund and subsequently died. Post-mortem examination identified hepatomegaly and splenomegaly as the most severe macroscopic abnormalities. Histopathological examination revealed extensive hepatic and splenic necrosis. Transmission electron microscopy (TEM) identified virions of a size (circa 78 nm diameter) and morphology consistent with ARV in both the liver and the small intestinal (SI) contents. Nucleic acid extracted from pooled liver and spleen was positive on both a pan-reovirus nested PCR targeting the RNA-dependent RNA polymerase gene and a PCR using primers specific to the ARV sigma C protein gene. Virus isolated from the liver and the SI contents was characterised by a syncytial-type cytopathic effect, a reovirus-like appearance on TEM and sequence identical to that from PCR of tissues. In situ hybridisation confirmed co-localisation of ARV with lesions in the liver and spleen, implicating ARV as the causative agent. Splenic lymphoid atrophy and necrotic stomatitis associated with Aspergillus fumigatus infection were consistent with generalised immunosuppression and resultant opportunistic infection.
  
  
  CONCLUSIONS
  The pathology and comprehensive virus investigations in this case indicate ARV as the primary pathogen in this magpie, with concurrent secondary infection subsequent to immunosuppression, as has been observed with reoviral infections in other bird species. ARV should be considered as a differential diagnosis for magpie, and potentially other corvid, disease and mortality incidents. This is the first demonstration of ARV-associated mortality in a wild bird in Britain. The prevalence and significance of ARV infection in British wild birds, and its implications for poultry and captive bird health, are currently unknown.
authors.affiliation: Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK. becki.lawson@ioz.ac.uk.
authors.forename: Becki
authors.initials: B
authors.lastname: Lawson
authors.affiliation: Animal and Plant Health Agency (APHA), Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, UK. akbar.dastjerdi@apha.gsi.gov.uk.
authors.forename: Akbar
authors.initials: A
authors.lastname: Dastjerdi
authors.affiliation: Animal and Plant Health Agency (APHA), Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, UK. sonal.shah@apha.gsi.gov.uk.|School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD, UK. sonal.shah@apha.gsi.gov.uk.
authors.forename: Sonal
authors.initials: S
authors.lastname: Shah
authors.affiliation: Animal and Plant Health Agency (APHA), Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, UK. david.everest@apha.gsi.gov.uk.
authors.forename: David
authors.initials: D
authors.lastname: Everest
authors.affiliation: Animal and Plant Health Agency (APHA), Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, UK. alejandro.nunez@apha.gsi.gov.uk.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Núñez
authors.affiliation: Finn Pathologists, One Eyed Lane, Weybread, Diss, Norfolk, IP21 5TT, UK. ann.pocknell@finnpathologists.com.
authors.forename: Ann
authors.initials: A
authors.lastname: Pocknell
authors.affiliation: Animal and Plant Health Agency (APHA), Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, UK. daniel.hicks@apha.gsi.gov.uk.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hicks
authors.affiliation: Animal and Plant Health Agency (APHA), Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, UK. d.horton@surrey.ac.uk.|School of Veterinary Medicine, University of Surrey, Guildford, Surrey, GU2 7XH, UK. d.horton@surrey.ac.uk.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Horton
authors.affiliation: Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK. a.cunningham@ioz.ac.uk.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Cunningham
authors.affiliation: Animal and Plant Health Agency (APHA), Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, UK. richard.irvine@apha.gsi.gov.uk.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Irvine
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000473:pathology*; D017809:Fatal Outcome; D005260:Female; D030101:Orthoreovirus, Avian / Q000235:genetics / Q000302:isolation & purification*; D046109:Passeriformes; D010802:Phylogeny; D012088:Reoviridae Infections / Q000473:pathology / Q000662:veterinary*; D006113:United Kingdom