Clinical manifestations of diarrhea in calves infected with rotavirus and enterotoxigenic Escherichia coli

Abstract

The susceptibility of gnotobiotic, colostrum-deprived or suckling calves to 4 bovine rotavirus isolates was age dependent. Calves older than 7 days remained clinically normal, although they excreted virus in their feces and subsequently developed antibody against the virus. Enterotoxigenic E. coli, fed to gnotobiotic, colostrum-deprived or suckling calves ranging in age from a few hours to 26 days old, only caused diarrhea in animals younger than 24 h old. Diarrhea was consistently induced in 1-2 wk old calves infected with both enterotoxigenic E. coli and rotavirus. Diarrhea appeared after a rotavirus incubation period of .apprx. 3 days and was independent of the order in which the 2 microbial agents were given, the age of the calf or the level of circulating rotavirus antibodies. The disease episode coincided with the excretion of rotavirus, rather than enterotoxigenic E. coli, in the feces. Infection with enterotoxigenic E. coli became established within 24 h of inoculation and in older calves enterotoxigenic E. coli was often excreted in very small numbers and for a longer period than rotavirus.