A team of scientists has, for the first time in India, identified and genetically characterised a virus that often causes rapid death in captive psittacine birds, raising concerns about the health of exotic pets and conservation of threatened parrot species.
Psittacine, which means relating to or resembling a parrot, describes the bird family Psittacidae and order Psittaciformes. It includes budgerigars, cockatiels, cockatoos, lovebirds, macaws, and parakeets.
Research team
The team, led by Pankaj Deka and Sangeeta Das of the Assam Veterinary and Fishery University in Guwahati, found and characterised parrot bornavirus 4 (PaBV-4) circulating among captive psittacine birds in India. Their study was published in Scientific Reports.
The other members of the team are Ritam Hazarika, Parikshit Kakati, Bhaskar Choudhury, Suchanda Doloi, Abdul Kasheef, Sophia M. Gogoi, Sutopa Das, Rajeev Kumar Sharma, Saidul Islam, Mrinal Nath, Mihir Sarma, and Ilakshy Deka. They represent institutions in Assam and Gujarat.
They tested 83 psittacine birds from 13 species in aviaries in Assam, Karnataka, and West Bengal in 2020-2024. The birds included the African grey parrot, ochre-marked parakeet, yellow-collared macaw, eastern rosella, blue-crowned hanging parrot, rainbow lorikeet, and scarlet-chested parrot.
Three groups
They divided the birds into three groups: those showing clinical signs of proventricular dilatation disease (PDD), clinically healthy cage mates of suspected cases, and birds that had died of suspected PDD. Caused by avian bornavirus, PDD is a largely fatal viral condition affecting the digestive and nervous systems of birds.
“Amongst the avian bornaviruses discovered, PaBV belonging to species Orthobornavirus alphapsittaciforme possess the highest veterinary relevance and are considered to be a major threat to psittacine aviculture,” the researchers said. “Since the discovery of PaBV in psittacine birds suffering from PDD in 2008, PaBV infections have been reported worldwide.”
Upon testing cloacal swabs from live birds and brain and proventriculus tissue in dead ones, the team found 44 of the 83 birds tested were infected. ‘Cloacal’ refers to a rear orifice serving as the combined digestive, urinary, and reproductive outlet in birds, reptiles, amphibians, and most fishes.
Infection was detected in almost 88% of the dead birds and 19% of the apparently healthy cage mates, underlining how the virus can lurk without showing outward symptoms. The infected birds belonged to nine species whose conservation status ranged from near-threatened to endangered.
Potential risk
The scientists also found that brain tissue and cloacal swabs yielded higher detection rates in dead and live birds, respectively. Genetic analysis confirmed all positive samples had PaBV-4, a strain previously reported in Canada, Israel, Japan, South Korea, and the U.S.
The team found no patterns linking genetic clusters to host species, geography or timing. Suggesting this may reflect the global trade in psittacine birds, the researchers said their findings highlight risks to conservation based on breeding captive birds.
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