Outbreak of clostridial myocarditis in calves.

This paper describes the epidemiological and pathological features of an outbreak of clostridial myocarditis in calves due to Clostridium chauvoei. Four of seven two-month-old Hereford calves died in the course of a week. Their gross postmortem lesions were similar and consisted of irregular dark red areas of myocardial necrosis through the full thickness of the atrial and ventricular myocardium. No lesions were observed in skeletal muscle. The heart muscle had extensive multifocal areas of acute coagulative necrosis. The diagnosis was confirmed by a fluorescent antibody technique on tissue smears, by a streptavidin-biotin technique on formalin-fixed, paraffin-embedded tissues, and by a PCR technique specific for the 16S rRNA of C. chauvoei.

Effect of Shiga toxin 2 on water and ion transport in human colon in vitro.

Shiga toxin-producing Escherichia coli (STEC) colonize the lower segments of the human gastrointestinal tract, causing gastrointestinal and systemic diseases. In this study, the effects of Shiga toxin 2 (Stx2) on fluid absorption and ion transport in the human colon were examined. Net water movement (Jw) and short-circuit current (Isc) were simultaneously measured across the colonic mucosa incubated with crude or purified Stx2. Stx2 significantly inhibited the absorptive J(w) with no effect on the basal I(sc) after 60 min of exposure. These effects may be due to the inhibition of a nonelectrogenic transport system present in the surface colonic villus cells. Morphological studies of the colonic mucosa treated with crude or purified Stx2 demonstrated a selective damage in the absorptive villus epithelial cells. These findings suggest that Stx2 inhibits water absorption across the human colon by acting on a specific cell population: the mature, differentiated absorptive villus epithelium.