Occurrence of Newcastle disease in poultry population of Mizoram, India

A study was undertaken to survey the prevalence of viral diseases of poultry in Mizoram during March, 2013 to February, 2014. Out of 476 poultry carcasses examined, 208(43.69%) cases were diagnosed as viral diseases. Forty cases of Newcastle disease (8.40%) could be diagnosed based on the clinical history, signs, gross and histopathology, and confirmed by HA and HI tests with detection of the viral antigen. All age groups of birds were affected with morbidity and mortality rates of 35–50% and 25–35%, respectively and the highest incidence during the winter season followed by rainy and summer seasons. Most common signs were depression, emaciation, greenish or white diarrhea and edema of the head, face and wattles, while some birds developed respiratory signs like sneezing, gasping, nasal discharge and coughing. Post-mortem findings included pin-point haemorrhages at the tips of the proventriculus glands, hemorrhagic ulcers in intestinal wall and caecal tonsils, hemorrhagic tracheitis with congestion and catarrhal exudates. The spleen was enlarged, friable and appeared dark red or mottled, while the kidneys were enlarged, congested and swollen with urate deposition.Significant microscopic changes were haemorrhages and necrosis of the proventriculus mucosa with mononuclear cell infiltration. Caecal tonsil revealed haemorrhages, infiltration of heterophils in the lamina propria, lymphoid depletion and formation of germinal centres. There were sloughing of tracheal mucosa with loss of cilia and congestion, while brain sections revealed non-suppurative encephalitis, neuronal degeneration, gliosis and perivascular cuffing.