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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #80872
Title: PATHOGENICITY OF ESCHERICHIA COLI O157:H7 IN THE INTESTINES OF NEONATAL CALVES

Author
item Nystrom, Evelyn
item Bosworth, Brad
item CRAY, JR, WILLIAM - 3625-30-15
item MOON, HARLEY - IOWA STATE UNIV., AMES

Submitted to: Infection and Immunity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Cattle are an important reservoir of Shiga-like toxin-producing enterhemorrhagic Escherichia coli O157:H7, foodborne pathogens that cause severe diarrhea and sometimes kidney failure and death in humans. One way to reduce the risk of O157:H7 infections in humans is to reduce the level of E. coli O157:H7 in cattle. When, where, or how cattle become infected is not known. Weaned calves and adult cattle remain healthy after infection with E. coli O157:H7, but infected catle can shed O157:H7 in their feces for a long time. Newborn calves are often more susceptible to enteric infections than are older calves. We found that calves less than 36 hr old inoculated with E. coli O157:H7 strains developed diarrhea and had inflammation and tissue damage in both the large and small intestines by 18 hr postinoculation. The severity of diarrhea and inflammation, and the frequency and extent of damage to the intestinal surface, increased by 3 days postinoculation. We conclude that E. coli O157:H7 cause disease in neonatal calves. Prompt treatment or removal of E. coli O157:H7-infected calves will decrease the direct health risk to producers and veterinarians and will positively impact the safety of beef and dairy products by reducing the level of E. coli O157:H7 in cattle. The neonatal calf appears to be an excellent model for studying E. coli O157:H7 infections in cattle. Identification of ways to reduce E. coli O157:H7 infections in cattle will help reduce the risk of E. coli O157:H7 disease in humans.

Technical Abstract: Cattle are an important reservoir of Shiga-like toxin-producing enterohemorrhagic Escherichia coli (EHEC) O157:H7, foodborne pathogens that cause hemorrhagic colitis and hemolytic uremic syndrome (HUS) in humans. EHEC O157:H7 are not pathogenic in calves more than 3 weeks old. Our objective was to determine if EHEC O157:H7 are pathogenic in neonatal calves. Calves less than 36 hr old inoculated with EHEC O157:H7 strains developed diarrhea and enterocolitis with attaching and effacing (A/E) lesions in both the large and small intestines by 18 hr postinoculation. The severity of diarrhea and inflammation, and also the frequency and extent of A/E lesions, increased by 3 days postinoculation. EHEC O157:H7 disease in neonatal calves was similar to that in neonatal piglets. We conclude that EHEC O157:H7 are pathogenic in neonatal calves. The neonatal calf model is relevant for studying the pathogenesis of EHEC O157:H7 infections in cattle. It should also be useful for identifying ways to reduce EHEC O157:H7 infections in cattle and thus reduce the risk of EHEC O157:H7 disease in humans.