Clinicopathological and Molecular Investigation of Newcastle Disease in Chickens in and Around Hyderabad, Telangana, India

Newcastle disease (ND), caused by Newcastle disease virus (NDV), remains a major threat to poultry production in India despite routine vaccination. This study evaluated the clinicopathological and molecular features of ND in chickens from farms in and around Hyderabad, Telangana, from July to December 2025. Carcasses from 45 farms and from submitted cases were examined by necropsy and histopathology, and NDV was confirmed by reverse transcription PCR (RT-PCR) targeting the fusion (F) gene. Of 1,450 broiler chickens necropsied, 759 had gastrointestinal disease, and ND accounted for 90 cases (case prevalence 11.86%). These cases occurred in four outbreaks involving 6,000 birds, with 90 deaths (mortality 1.50%). No cases were seen in birds under 15 days old. Mortality was 1.77% in the 15–21-day age group, 1.80% in the 22–28-day age group and 0.67% in birds older than 29 days. Gross lesions included petechial haemorrhages at the tips of the proventricular glands, intestinal congestion, haemorrhages and ulcers, and enlarged, haemorrhagic, necrotic caecal tonsils. Histopathology showed sloughing and necrosis of the proventricular epithelium, heterophilic infiltration, villous fusion and degeneration in the intestine, and necrosis of caecal tonsil tissue. RT-PCR produced the expected 304 bp F-gene amplicon in positive samples, confirming NDV infection. These findings confirm active circulation of NDV in the study area and underline the need for regular surveillance, strict biosecurity and consistent vaccination in both commercial and backyard flocks.