Exotic Newcastle disease in a game chicken flock

A sudden increase in mortality preceded by a shore history of respiratory s igns and diarrhea, occurred in a backyard flock of 48 game chickens in the Central Valley of California. Necropsy findings included severe generalized linear hemorrhages and/or ulcers in the digestive tract, larynx, and trach ea. Histology revealed severe multifocal hemorrhages and necrosis in the mu cosa of the respiratory and digestive tracts, vasculitis, and necrosis of l ymphoid tissue. The birds were serologically negative to Newcastle disease virus; this was consistent with an acute infection. The avian paramyxovirus type I isolated was characterized as velogenic viscerotropic Newcastle dis ease virus. A thorough epidemiologic investigation was carried out, and no other premises were found to have birds with clinical signs or evidence of exposure. The entire outbreak was limited to the original backyard flock an d resolved within 14 days of the onset of clinical signs.