Surveillance of wild and domestic birds reveals circulation of velogenic and lentogenic strains of Avian Avula virus-1 in Andhra Pradesh and Telangana states of India

Asian countries including India, harbor diverse range of Avian Avulavirus-1 genotypes and sub-genotypes resulting in severe ND outbreaks which causes major losses to the poultry sector. The rising number of reports of virulent AAvV-1 in wild birds in other parts of the world, raised concern as to ascertain the role of avian species other than chicken in the transmission and spread of the disease in India as well. We investigated 252 samples collected from clinically healthy birds of eleven avian species belonging to eight different orders. AAvV-1 could be isolated from eighteen samples including eleven from pekin ducks (27.5%), two from rock pigeons (11.7%), one each from spot-billed pelican (6.2%), Japanese quail (4.7%), domestic turkey (2.9%), domestic goose (6.2%) and emu (4.0%). Strains isolated from spot-billed pelican, rock pigeons and emu are found to be velogenic, while those isolated from pekin ducks, Japanese quail, domestic turkey and goose are lentogenic based on biological and molecular characterization studies. Screening of wild and domestic birds in their natural habitats revealed presence of both velogenic and lentogenic AAvV-1 strains and provided strong evidence that these birds play an important role in spread of Newcastle disease in the Indian subcontinent despite stringent vaccination protocols.