Additional backgroundVirulent Newcastle disease is a contagious and fatal viral disease affecting the respiratory, nervous and digestive systems of birds and poultry. The disease is so virulent that many birds and poultry die without showing any clinical signs. A death rate of almost 100 percent can occur in unvaccinated poultry flocks. Virulent Newcastle disease can infect and cause death even in vaccinated poultry.Clinical signs of virulent Newcastle disease include: sudden death and increased death loss in the flock; sneezing; gasping for air; nasal discharge; coughing; greenish, watery diarrhea; decreased activity; tremors; drooping wings; twisting of the head and neck; circling; complete stiffness; and swelling around the eyes and neck.
Source: U.S. Department of Agriculture Animal and Plant Health Inspection Service
