Bornaviruses are enveloped, non-segmented negative strand RNA viruses. They replicate in the host cell nucleus, cause persistent infections, are non-cytopathic in cell culture and are highly cell-associated. The first avian bornavirus (ABV) was identified in 2008 and is the etiologic agent of proventricular dilatation disease (PDD) in parrots. ABV replicates in many organs, especially the central nervous system. It can be intermittently detected in cloacal swabs and feather follicles. During surveys to determine the possible origins of ABV we examined multiple oropharyngeal/fecal swabs and brain samples from multiple species of geese, ducks and mute swans. Reverse transcription PCR was used to screen RNA samples from swab samples from 409 Canada geese (Branta canadensis) and 200 mute swans (Cygnus olor) of which 3.6% tested positive for ABV. Brain tissues were subsequently collected from 25 Canada geese and 192 mute swans and 200 ducks of multiple species; ABV was detected in 52% and 23% of Canada goose and mute swan brain samples respectively. ABV was also detected in 11% of brain samples from hunter-harvested ducks. Of the major duck species tested, 7/84 (8.3%) of redheads (Aythya americana), 4/63 (6.3%) of northern pintails (Anas acuta) and 6/25 (24%) of gadwalls (Anas strepera) were ABV positive. Among other duck species, 2/9 (22%) northern shovelers (Anas clypeata), 1/10 (10%) mallards (Anas platyrhynchos), and 4/12 (33%) American widgeons (Anas americana) were also positive. RT-PCR products obtained from Canada geese, mute swans and ducks were sequenced, revealing that two different genotypes of ABV were circulating in these waterfowl. ABV genotypes 4 (ABV4) was recovered from ducks in Texas while a distinct genotype (ABV-CG) was recovered from geese and swans across the United States. ABV-CG was also detected in a small number of embryonated mallard duck eggs obtained from commercial breeders. ABV-CG appears, under some circumstances, to cause acute encephalitis or proventricular dilation disease in geese and swans. 2013 by Nova Science Publishers, Inc. All Rights Reserved.
