Circovirus infection in Croatian population of Eurasian griffon vultures (Gyps fulvus)

Circoviruses cause diseases in a wide range of hosts, including avian species. One of the most studied circoviruses is beak and feather disease virus (BFDV), which has spread worldwide due to global trade of birds and characteristics of the virus that allow it to persist in the environment. The Eurasian griffon vulture (Gyps fulvus) is one of the largest birds in the world and is among several vulture species that are considered endangered today, and currently the only remaining vulture species in Croatia. Several juvenile Eurasian griffon vultures undergoing rehabilitation at the Beli Visitor Centre and Rescue Centre for Griffon Vultures on the island of Cres, Croatia, had feather lesions similar to those caused by BFDV in psittacine birds. Signs included partially retained feather sheaths, discoloration and circumferential constrictions of the feather shafts, gnawed feather tips, keratin and egg deposits near the feather shafts, as well as feather breakage and spontaneous feather loss. Feather samples were collected for molecular detection of viral pathogens and macroscopic detection of ectoparasites; blood samples were taken for complete blood count (CBC), biochemical analysis and oxidative stress analysis. The molecular analysis confirmed a circovirus infection, which was supported by the blood analyses indicating a viral infection. The collected ectoparasites were identified as chewing lice - Colpocephalum turbinatum and Falcolipeurus quadripustulatus, which have previously been detected in Eurasian griffon vultures. To our knowledge, this is the first report of circovirus infection in Eurasian griffon vultures. Considering that circoviruses are highly contagious, very resistant and easily transmissible, it is extremely important to perform continuous monitoring in order to improve the breeding and survival conditions of Eurasian griffon vulture populations worldwide.