This paper describes visceral lesions induced by inoculation of one-day-old broiler chicks with an avian reovirus strain (S-1133) by oral and foodpad routes. The bursa of Fabricius, intestine, liver, spleen and heart of five birds from inoculated and control groups were collected in the periods of 24, 48, 72 hours and at weekly intervals from 1 to 8 weeks post inoculation for histopathological examination. Interstitial myocarditis was observed 48 hours post inoculation, pericarditis and necrotic myocarditis were seen in the first week post inoculation. The pericardium presented lymphoid follicles at 2 weeks post inoculation and in the subsequent periods there was progressive fibrosis seen until 8 weeks post inoculation. In the liver, infiltration of heterophils and mononuclear cells was observed 72 hours post inoculation, followed by degeneration and necrosis of hepatocytes at one week post inoculation. Lymphoid follicles and heterophilic infiltration were seen from 2 to 8 weeks post inoculation. The spleen presented a progressive necrosis from 48 hours to one week post inoculation and at 2 weeks post inoculation hyperplasia lymphoid was observed in the splenic tissue. No lesions were seen in the other examinated organs. Visceral lesions were similar occurring simultaneously in both inoculated groups, nevertheless the lesions were more severe in the group inoculated via footpad.
Reoviridae; Domestic Avian
