Pathological characterization in chickens of a velogenic Newcastle disease virus isolated from guinea fowl

Abstract

A flock of 160 six-week-old Harco cockerels was inoculated intramuscularly with a local Nigerian isolate of velogenic Newcastle disease virus (NDV) isolated from a dead guinea fowl. The birds came down with clinical signs on day 3 postinoculation (PI). The major signs were depression, greenish diarrhea, paralysis, opisthotonus and torticollis. Morbidity was 100% but mortality was 92%. By day 18 PI torticollis was the only sign persisting in some of the birds. The major gross lesions were hemorrhages in the proventricular mucosa, hemorrhagic ulcers in the intestines and transient atrophy of the lymphoid organs. Sections of the organs showed lymphocytic necrosis and depletion of the lymphoid organs, endotheliosis, gliosis and perivascular cuffing of the cerebrum and cerebellum. The above observations showed that the isolate was a viscerotropic velogenic strain. It is suggested that the hemorrhagic ulcers in the intestines could be regarded as diagnostic for viscerotropic velogenic NDV in the absence of epizootiological evidence of avian influenza.