High Mortality in Terns and Gulls Associated with Infection with the Novel Gull Adenovirus.

High mortality in Caspian Terns (Hydroprogne caspia) and Great Black-headed Gulls (Larus ichthyaetus), was recorded on the northeastern shores of the Caspian Sea in June 2013. Retrospective high throughput sequencing of archived tissue samples conducted in 2018 revealed the presence of the recently identified novel gull adenovirus similar to that associated with mortality in gulls in the Netherlands in 2001. We suggest that that this gull adenovirus specifically can be considered as an emerging threat to the health and conservation of gulls and terns.