Is the prevalence and shedding concentrations of E. coli O157 in beef cattle in Scotland seasonal?

The prevalence of Escherichia coli O157 in Scottish beef cattle at abattoir was found to be greater during the cooler months [11.2% (95% CI, 8.4–13.9%)] compared to the warmer months [7.5% (95% CI, 5.4–9.6%)]; the reverse of seasonality of human infections. However, high shedding beef cattle (excreting >10 4 g −1) appear to shed greater concentrations of E. coli O157 in the warmer months which may partly explain increased human infection seasonality at this time.