Characterization of a New Species of Adenovirus in Falcons

Abstract

ABSTRACT In 1996, a disease outbreak occurred at a captive breeding facility in Idaho, causing anorexia, dehydration, and diarrhea or sudden death in 72 of 110 Northern aplomado falcons ( Falco femoralis septentrionalis ) from 9 to 35 days of age and in 6 of 102 peregrine falcons ( Falco peregrinus ) from 14 to 25 days of age. Sixty-two Northern aplomado and six peregrine falcons died. Epidemiologic analyses indicated a point source epizootic, horizontal transmission, and increased relative risk associated with cross-species brooding of eggs. Primary lesions in affected birds were inclusion body hepatitis, splenomegaly, and enteritis. The etiology in all mortalities was determined by molecular analyses to be a new species of adenovirus distantly related to the group I avian viruses, serotypes 1 and 4, Aviadenovirus . In situ hybridization and PCR demonstrated that the virus was epitheliotropic and lymphotropic and that infection was systemic in the majority of animals. Adeno-associated virus was also detected by PCR in most affected falcons, but no other infectious agents or predisposing factors were found in any birds. Subsequent to the 1996 epizootic, a similar disease caused by the same adenovirus was found over a 5-year period in orange-breasted falcons ( Falco deiroleucus ), teita falcons ( Falco fasciinucha ), a merlin ( Falco columbarius ), a Vanuatu peregrine falcon ( Falco peregrinus nesiotes ), and gyrfalcon × peregrine falcon hybrids ( Falco rusticolus / peregrinus ) that died in Wyoming, Oklahoma, Minnesota, and California. These findings indicate that this newly recognized adenovirus is widespread in western and midwestern North America and can be a primary pathogen in different falcon species.