Prevalence of Newcastle Disease Virus in Wild and Migratory Birds in Haryana, India.

Newcastle disease virus (NDV) can infect approximately 250 avian species and causes highly contagious Newcastle disease (ND) in domestic poultry, leading to huge economic losses. There are three different pathotypes of NDV, i.e., lentogenic, mesogenic, and velogenic. Wild resident (wild) and migratory birds are natural reservoirs of NDV and are believed to play a key role in transmitting the virus to domestic poultry. The present study was conducted to determine the prevalence of NDV in wild and migratory birds in the state of Haryana, India, during two migratory seasons (2018-19 and 2019-20). In total 1379 samples (1368 choanal swabs and 11 tissue samples) were collected from live ( n = 1368) or dead birds ( n = 4) belonging to 53 different avian species. These samples belonged to apparently healthy ( n = 1338), sick ( n = 30), and dead ( n = 4) birds. All samples were tested for NDV by real-time reverse transcription-PCR using M gene specific primers and probe. Of the 1379 samples, 23 samples from wild birds [ Columba livia domestica ( n = 12, 52.17%), Pavo cristatus ( n = 9, 39.13%), and Psittaciformes ( n = 2, 8.69%)] were found positive for NDV. Only one of the 23 samples (from P. cristatus ) was positive for F gene, indicating it to be a mesogenic/velogenic strain. These results indicate that both lentogenic and velogenic strains of NDV are circulating in wild birds in Haryana and that further studies are needed to characterize NDV strains from wild/migratory birds and domestic poultry to determine the extent of virus transmission among these populations. This study considers the disease transmission risk from domestic pigeons and parrots to commercial poultry and vice versa, and the results emphasize the need for strict biosecurity strategies to protect commercial poultry in the region.