Pathogenicity and immunogenicity in chickens of Newcastle disease viruses isolated from wild ducks. Brief report.

Three Newcastle disease viruses (NDV) isolated from wild ducks in Japan were evaluated for their biological activities, pathogenicity and immunogenicity against one-day-old chickens. One isolate was of the mesogenic type and the other two were of the lentogenic type for chicken. The lentogenic isolates could induce enough immunity in chickens to protect them from challenge with a virulent strain of NDV.