Pathological and Bacteriological Findings of Foals Infected with Rhodococcus equi

Abstract

Ninety one foals were necropsied and examined for Rhodococcus equi infection at Animal Clinic Center of Nosai Hidaka, Hidaka Livestock Hygiene Service Center, and School of Veterinary Medicine and Animal Sciences, Kitasato University from 1992 to 1996. Forty-nine of 91 cases had been clinically diagnosed as R. equi pneumonia, while the remaining 42 as non-R. equi pneumonia (14 foals), arthritis (6 foals), and others (22 foals). Pathologically, 89 cases were shown to have suppurative pneumonia with abscesses, and the remaining 2 cases had intestinal involvement without pulmonary lesions. Bacteriologically, virulent R. equi was isolated from lesions of all the 91 foals. Based on the pathology and bacteriology, 91 cases were classified into 4 disease types: pneumonia type (40 cases; suppurative bronchopneumonia), enteritis type (2 cases; ulcerative enteritis associated with suppurative lymphadenitis of the intestine), mixed type (23 cases; pneumonia, enteritis, and intestinal lymphadenitis), and transitional type (26 cases; pneumonia and intestinal lymphadenitis).