Scanning electron microscopy of abomasium and intestine of gnotoxenic calves infected either with rotavirus, coronarivus or enteropathogenic Escherichia coli or with rotavirus and E. coli.

Neonatal calf diarrhoea induced with several agents of infection was studied by scanning electron microscopy. In a gnotoxenic calf infected with E. coli K99+ Ent+, slight lesions of the small intestine were observed and desquamation or puffiness of microvilli occurred. In rotavirus-infected calves, the abomasum was covered with abudant mucous film and appeared to be desquamated. In the small intestine, no desquamation of epithelium was observed. Inoculation of the rotavirus and E. coli induced severe diarrhoea. The whole digestive tract, even the abomasum and colon, was eroded. Coronavirus induced marked lesions in all levels of the intestine. These results demonstrate unequivocally the pathogenic properties of the three infectious agnets, the synergistic effect of E. coli and rotavirus. Furthermore, the importance of the abomasum in neonatal diarrhoea is emphasized.