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United States Department of Agriculture

Agricultural Research Service

Title: Environmental and Food Safety Aspects of Escherichia Coli O157:h7 Infections in Cattle

Authors
item Rasmussen, Mark
item Casey, Thomas

Submitted to: Critical Reviews in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 15, 2001
Publication Date: N/A

Interpretive Summary: The presence of Escherichia coli O157:H7 in cattle illustrates the complex, interrelated nature of the environment, livestock production practices, food safety, and the science of microbiology, particularly microbial ecology. E. coli that cause intestinal bleeding, including E. coli O157:H7, can cause severe human diseases that can be debilitating and life threatening. Cattle are currently considered to be the definitive source for E. coli O157:H7 in the food supply, but this view may be simplistic and incomplete. E. coli O157:H7 appears widespread among U.S. cattle herds, while individual animal prevalence is low and transient. Most individual animals appear to be a transient reservoir for E. coli O157:H7, although the issue of carrier animals still remains unresolved. The problem of E. coli O157:H7 increases during the summer and fall months, but the environmental factors that contribute to this increase are poorly understood. Possible environmental factors that may influence E. coli O157:H7 shedding in cattle include livestock feed and waste handling practices as well as insects and microbial interactions in soil and water. Studies of E coli O157:H7 ecology in cattle and the environment have been limited, but they suggest that a consideration of other independent, environmental sources of this microbe seems appropriate. The results of this research will greatly benefit producers, as well as human medicine, which will consequently affect the American consumer.

Technical Abstract: The presence of Escherichia coli O157:H7 in cattle illustrates the complex, interrelated nature of the environment, livestock production practices, food safety, and the science of microbiology, particularly microbial ecology. E. coli that cause intestinal bleeding, including E. coli O157:H7, can cause severe human diseases that can be debilitating and life threatening. Cattle are currently considered to be the definitive source for E. coli O157:H7 in the food supply, but this view may be simplistic and incomplete. E. coli O157:H7 appears widespread among U.S. cattle herds, while individual animal prevalence is low and transient. Most individual animals appear to be a transient reservoir for E. coli O157:H7, although the issue of carrier animals still remains unresolved. Epidemiological studies of the cattle production system have not clearly identified risk factors or management practices that affect E. coli O157:H7 prevalence in cattle feces. The problem of E. coli O157:H7 increases during the summer and fall months, but the environmental factors that contribute to this increase are poorly understood. Possible environmental factors that may influence E. coli O157:H7 shedding in cattle include livestock feed and waste handling practices as well as insects and microbial interactions in soil and water. Studies of E coli O157:H7 ecology in cattle and the environment have been limited, but they suggest that a consideration of other independent, environmental sources of this microbe seems appropriate. The natural ecology of cholera may serve as a useful environmental model for pursuing additional environmental research on the occurrence and transmission of E. coli O157:H7 in nature.

Last Modified: 4/20/2014
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