In the past 10 years, a significant number of kea (Nestor notabilis) in the AZA Kea SSP population have shown clinical signs consistent with disease caused by avian bornavirus (ABV). The SSP requested antemortem testing of each bird to determine the prevalence of the virus within the population. Blood samples and common choanal/cloacal swabs were collected from each bird and submitted for reverse transcriptase polymerase chain reaction (RT-PCR) testing for ABV. Forty-eight birds were tested, which represented 96% of the living population. Thirty of 48 birds tested positive (62.5%) on either blood or choanal/cloacal swab (or both). Six institutions had negative results in all birds, three institutions had positive results in all birds and two institutions had both positive and negative results. Of the 48 birds tested, 13 (27.1%) have since died, and necropsy and histopathology records were reviewed. Eleven of 13 of these birds tested ABV positive prior to death, and 2/13 tested ABV negative prior to death. None of the deceased birds had pathologic lesions considered definitive for ABV. Tissue samples (either frozen, formalin fixed, or paraffin embedded) were submitted from 9 birds for ABV PCR testing. All tissue samples tested were negative for ABV. Based on the data collected to date, there is no definitive evidence to support ABV as a direct cause of morbidity or mortality. However, based on a retrospective records review, which included the individuals in this study as well as those that had died prior, there have been several birds that have shown clinical signs that would be considered consistent with ABV. Further study is warranted to determine if ABV can be linked to morbidity and mortality in the kea SSP population.
The authors would like to thank each and every kea-holding institution for their willingness to participate in this study.