Histopathological changes in Newcastle disease affecting racing pigeons in Japan.

Abstract

Newcastel disease (ND) occurred among flocks of racing pigeons in Japan from 1983 to 1984. Diseased pigeons exhibited nervous symptoms and diarrhea with a 13% of mortality rate. Thirty-three of the affected pigeons from 9 flocks were subjected to pathological examination. No characteristic gross changes were observed. In 15 of the 33 pigeons including 10 birds (group 1) from which ND viruses (NDV) were isolated and 5 affected birds (group 2) which had no hemagglutination-inhibition (HI) antibodies and in which no attempt was made to isolate NDV, the main histopathological changes consisted of necrosis or atrophy of the lymphoid tissue in the spleen as well as in the bursa of Fabricius and thymus, splenitis, nephritis, and hepatitis, in addition to non-purulent encephalomyelitis. In the others (18 of 33 pigeons; group 3) in which HI antibodies were detected but NDV was not isolated, the lesions consisted of hyperplasia of the lymphoid tissue in the spleen, follicular aggregation of lymphoid cells in the kidney and non-purulent encephalomyelitis. Based on the histopathological changes, it was considered that the viscerotropic and neurotropic strains of NDV had affected flocks of racing pigeons in Japan.