Pathological Studies on Newcastle Disease

II. Lesions Induced by TCND Strain

Abstract

pneumoencephalitis was induced in 57-day-old and 1-day-old chicks by means of single intracerebral IC and intra-aerosaccular IA inoculation with the TCND strain of Newcastle disease virus.
Severe nervous symptoms, such as leg weakness, paralysis, tremor, and depression, were found in the IC groups at both ages. Some 1-day-old chicks of these groups died 5 or 6 days postinoculation. No respiratory symptoms were seen any group.
Lesions in the central nervous system were the most prominent in the 57-day-old IC group of the four inoculated ones. They were characterized by disseminated nonpurulent encephalomyelitis and composed of nerve cell degeneration, glial proliferation, and perivascular cell infiltration. The 1-day-old IC group, however, showed only mild lesions, in spite of severe nervous symptoms.
Changes in the respiratory tract, such as peribronchial lymphoid cell infiltration, necrosis of infiltrating lymphoid cells, and septal pneumonia-like feature, were found in the 4 groups, except the 1-day-old IC group.
Of the other organs, the bursa of Fabricius showed interesting changes which were composed of necrosis and the disappearance of follicular lymphoid cells. Simultaneously, reticuloendothelial cells supporting the follicles began to proliferate, and necrotic lymphoid cells were replaced.