Aquatic Bird Bornavirus-Associated Disease in Free-Living Canada Geese ( Branta canadensis ) in the Northeastern USA.

During the winter of 2013-14, 22 Canada geese ( Branta canadensis ) were admitted to the Wildlife Clinic at the Cummings School of Veterinary Medicine at Tufts University with nonspecific neurologic abnormalities and emaciation. Five of these geese, along with three geese that were submitted dead, were evaluated via histopathology, immunohistochemistry, and reverse transcription PCR (RT-PCR) for bornaviruses. Histopathologically, six of the eight birds had lymphoplasmacytic encephalitis. One bird, which also had encephalitis, had a dilated esophagus. Lead poisoning, West Nile virus, avian influenza, and avian paramyxovirus infection were excluded from the diagnosis. Brain tissue from all eight geese was positive for bornaviral N-antigen on immunohistochemistry. Frozen brain tissue from five birds was available for bornavirus RT-PCR. Three of the five birds were positive for the bornavirus M gene. Formalin-fixed paraffin-embedded brain tissue was evaluated on the remaining three geese via RT-PCR, with one of these geese testing positive. A bornavirus was subsequently cultured in duck embryo fibroblasts from the brain of one Canada Goose. This virus genome was sequenced, and the virus was identified as aquatic bird bornavirus 1. We were unable to identify any unusual features of this genome that would account for its apparent pathogenicity, given that subclinical infection with bornavirus in waterfowl is common in North America.