Actinobacillus equuli Infection Involving the Central Nervous System of a Piglet

Abstract

Pathological and bacteriological examinations were performed on an 80-day-old piglet demonstrating growth retardation since birth. Anorexic and listless, the animal subsequently became depressed and had difficulty standing. It died of disease in the course of four days. Macroscopic examination disclosed congestion throughout the body and verrucose endocarditis in both sides of the atrioventricular valves. In histological terms, emboli of small gram-negative rods accompanied by micro-abscesses were scattered in capillaries and arterioles throughout the body, including the central nervous system. Pure Actinobacillus equuli was isolated from endocardial lesions, the brain, and many other visceral organs. These findings suggest that lesional involvement of the central nervous system followed endocarditis and bacteremia caused by A. equuli infection. Its emergence when the piglet was already 80 days old may be one reason why the condition followed a sub-acute course of development.