Outbreaks of Diarrhea in Nursing Piglets Presumably Associated with Isospora suis

Abstract

From April to August, 1985 on a swine farm in Akita Pref., diarrhea was observed in various groups of nursing piglets. During this period, 350 heads (3 to 20 days old) out of 435 Raised on the farm exhibited intermittent diarrhea ranging in color from white to gray. The mortality rate along with culling increased from 8.6 to 16.8% from about 5% during the normal period. Two diarrheal piglets were sacrificed for pathological, bacterological and virological examinations. At autopsy, a slight catarrhal lesion was observed in the small intestines, although no other gross lesions were found. Histopathologically, degeneration of the epithelial cells, coccidial infection of the epithelial cells and slight. infiltration of eosinophils in the lamina propria were observed in ileal lesions. Neither pathogenic bacteria nor viruses were isolated from these pigs. Parasitological fecal examinations were conducted in 4 piglets showing diarrhea in the same herd in addition to those 2 autopsied cases (6 in total), and Isospora suis was isolated from 2 piglets. From these findings, it is considered that this incidence was associated with Isospora suis.