Vaccinating cows against the O157 strain of E. coli bacteria might reduce by nearly 85 percent human cases of the disease, British researchers said Monday.

The bacteria, which cause severe gastrointestinal illness and even death in humans, are spread by consuming contaminated food and water, or by contact with livestock faeces in the environment.

In addition to devastating personal losses, the economic costs can be substantial. In the United States, the costs of healthcare, social care, and lost productivity come to around 600 million US dollars per year, whereas costs to the food industry from product recalls and reduced trade can run to tens of millions of dollars.

Cattle are the main reservoir for E. coli O157, and two vaccines for the bacteria are now available, but cost and regulatory issues have hampered their widespread use.

In their study, researchers from the University of Glasgow and other U.K. institutions used veterinary, human surveillance, and molecular data to examine the risk of E. coli O157 transmission from cows to humans, and to evaluate the efficacy of vaccinating cattle.

They found that the risk of E. coli O157 infection is particularly significant when the cattle are "super-shedding" -- excreting extremely high numbers of bacteria in their faeces for a limited period of time. Vaccines against the bacteria exist that can reduce super-shedding.

Because the currently available vaccines target bacterial shedding rates, the researchers predicted that vaccinating cow could reduce human cases by nearly 85 percent, far higher than the 50 percent predicted by studies simply looking at the vaccines' efficacy in cattle.

The findings, published in the US journal Proceedings of the National Academy of Sciences, strongly support adoption of the vaccines by the livestock industry, said the researchers.

"We conclude that vaccination of cattle, the major reservoir for E. coli O157, could be an especially effective public health control against a serious disease," they wrote in their paper.

"While more work is needed to calculate the cost of a vaccination program, the public health justification must be taken seriously," lead author Louise Matthews of the University of Glasgow said in a statement.