Clinicopathology of meningoventriculitis due to Streptococcus bovis infection in neonatal calves.

Three neonatal calves ranging in age from 4 to 14 days were examined pathologically and bacteriologically. The calves showed depression, anorexia, pyrexia, and difficulty or inability to stand followed by cloudiness of the ocular aqueous humor or cornea. Autopsy revealed congestion, petechiae, and cloudy areas in the meninges. Histologically, the central nervous system (CNS) lesions were prominent and limited to the meninges where fibrinous exudate and infiltrations of neutrophils, macrophages, and lymphocytes were present. There were mild or slight degrees of choroid plexitis and ependymitis. Endophthalmitis was seen as a concurrent lesion in all cases. Fibrinous or fibrinopurulent changes were found in the peritoneum and epicardium as well as in several other organs. Numerous Gram-positive cocci were detected in affected areas of the whole body. Bacteriologically, Streptococcus bovis was isolated from all examined materials consisting of the brain, cerebrospinal fluid, ocular aqueous humor, and several other organs. These results suggest that the lesions were associated with infection of the organism and that the present cases were in the process of septicemia.