Vaccinate cattle to reduce human E. coli cases

Scottish research suggests that vaccinating cattle against E. coli O157 could reduce the number of humans affected by the bacterium by 85%. Vaccines that are available for cattle are rarely used, but the study shows the public health benefits could be significant.

A University of Glasgow research team led a team of researchers from the University of Edinburgh, the Royal Veterinary College, Scotland’s Rural College, Health Protection Scotland and the Scottish E. coli O157/VTEC Reference Laboratory in a study of E. coli O157 vaccination.

The study, published in the online journal PNAS, used veterinary, human and molecular data to examine the risks of E. coli O157 transmission from cattle to humans, and to estimate the impact of vaccinating cattle.

The risk of E. coli O157 infection is particularly significant when cattle are ‘super-shedding’ - excreting high numbers of bacteria in their faeces for a limited period of time. Vaccines against the bacteria can reduce super-shedding.

As a consequence, the researchers predict that vaccinating cattle could reduce human cases by nearly 85% - far higher than the 50% predicted by studies simply looking at the efficacy of current vaccines in cattle.

The figures provide strong support for the adoption of vaccines by the livestock industry, and work is now underway to establish the economic basis for such a program of vaccination. In addition, research is continuing in Scotland by the same collaborative group to develop even more effective vaccines that would further reduce the impact on human disease.

“E. coli O157 is a serious gastrointestinal illness,” said lead author Dr Louise Matthews, Senior Research Fellow in the Institute of Biodiversity, Animal Health and Comparative Medicine. “The economic impact is also serious - for instance, studies in the US suggest that healthcare, lost productivity and food product recalls due to E. coli O157 can cost hundreds of millions of dollars each year.

“Treating cattle in order to reduce the number of human cases certainly makes sense from a human health perspective and, while more work is needed to calculate the cost of a vaccination program, the public health justification must be taken seriously.”

The study was funded by the Wellcome Trust International Partnership Award in Veterinary Epidemiology, BBSRC Institute Strategic Programmes at The Roslin Institute and The Pirbright Institute and the Foods Standards Agency Scotland.