Vol. 10, Issue 12, Part H (2025)

Author(s): AP Surendar, KM Palanivel, S Saravanan, R Gopala Krishnamurthy and M Dharani

Abstract: Newcastle Disease (ND) remains one of the most devastating viral infections affecting poultry worldwide, with backyard poultry serving as an important reservoir for virus maintenance and dissemination. The present study investigated the molecular epidemiology of respiratory Newcastle disease virus (NDV) infections in backyard poultry reared under different management systems in Namakkal district, Tamil Nadu, India, during June 2016 to April 2017. A total of 239 samples comprising tracheal swabs, faecal swabs, necropsy specimens, and pox lesions were collected from 117 backyard poultry farms. Samples were subjected to virus isolation in specific pathogen-free embryonated chicken eggs (SPF-ECE), followed by molecular detection using reverse transcription polymerase chain reaction (RT-PCR) targeting the fusion (F) gene of NDV. Fourteen field isolates of NDV were confirmed, yielding a positivity rate of 25.9% among investigated farms. Molecular detection revealed a specific 356 bp amplicon corresponding to the F gene, identical in size to the LaSota vaccine strain, confirming the circulation of NDV in backyard poultry populations. Epidemiological analysis indicated higher incidence in birds below 24 weeks of age and in unvaccinated, free-ranging flocks. The study highlights the critical role of backyard poultry in the epidemiology of NDV and emphasizes the need for structured vaccination and biosecurity measures to prevent spillover between backyard and commercial poultry systems.

DOI: 10.22271/veterinary.2025.v10.i12h.2871