Generally chickens are highly susceptible with turkeys and pigeons less so. Ducks and geese are resistant, with peafowl, guineafowl, pheasant, and quail exhibiting mild disease. In chickens, outbreaks may be so severe that almost all of the affected flock may dies within 72 hours without showing clinical signs. A death rate of almost 100 percent can occur in unvaccinated poultry flocks. Exotic Newcastle can infect and cause death even in vaccinated poultry.
Canaries generally show a mild disease with low mortality.
Newcastle is probably one of the most infectious diseases of poultry in the world. Exotic Newcastle is so virulent that many birds die without showing any clinical signs. Newcastle disease has been reported in wild birds in Canada and the USA, and recently has been responsible for Cormorant die-offs. The natural reservoir is wild and domesticated birds. Exotic Newcastle affects the respiratory, nervous, and digestive systems.