ABSTRACT
Seasonal shedding of Escherichia coli O157:H7 in cattle is typically higher in the summer months and very low to nonexistent during the winter months. Interestingly, while this phenomenon is well documented and generally consistent, viable explanations are lacking. Ambient temperature is most often presented as the explanation for the seasonality of this pathogen and at £rst appearance would appear reasonable and logical. However, upon further examination of cattle prevalence and human outbreak data and consideration of our own research experience with E. coli O157:H7, we felt there must be a better explanation. Herein we discuss our own hypothesis regarding the seasonality of E. coli O157:H7 in feedlot cattle.
