September 17, 2013
Cattle Vaccinations Could Reduce Human E. Coli Infection Rates
redOrbit Staff & Wire Reports - Your Universe Online
The number of people who fall ill due to E. coli contamination could be drastically reduced if cattle were vaccinated against the bacterium, according to research published in the online edition of the journal Proceedings of the National Academy of Sciences (PNAS).
The E. coli O157 bacterium can result in severe gastrointestinal illness and is potentially fatal in humans. The pathogen is spread by consuming contaminated food and water, or by coming into contact with livestock feces in the environment, the researchers said. Cattle are the primary carrier of E. coli O157.
While there are vaccines available for bovinae, they are rarely used.
However, researchers from the University of Glasgow, the University of Edinburgh, the Royal Veterinary College, Scotland's Rural College, Health Protection Scotland, and the Scottish E. coli O157/VTEC Reference Laboratory reveal that vaccinations could reduce human E. coli cases by up to 85 percent if they were used more frequently.
The authors analyzed veterinary, human and molecular data to examine the risk of the bacterium being transmitted from cattle to people, as well as to estimate the impact of vaccinating the livestock. They found that the risk of infection is especially high when cattle are “super-shedding” or excreting higher-than-usual amounts of bacteria in their feces for a brief amount of time. This condition can be fixed using a vaccine, they explained.
“As a consequence, the researchers predict that vaccinating cattle could reduce human cases by nearly 85 percent, far higher than the 50 percent predicted by studies simply looking at the efficacy of current vaccines in cattle,” the University of Glasgow said in a statement. “These 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.”
Furthermore, Dr Louise Matthews, a senior research fellow in the university’s Institute of Biodiversity, Animal Health and Comparative Medicine and colleagues are continuing their work, hoping to develop more effective vaccines that would further reduce the impact of contamination in humans.
“E. coli O157 is a serious gastrointestinal illness. 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,” Dr. Matthews said. “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.”
However, there are some issues with the research team’s suggestion to vaccinate cattle.
One currently available vaccine is not fully licensed in the US because medicines intended for veterinary use in that country must demonstrate that the health of the animal receiving them is improved. However, E. coli O157 does not harm cattle, and assessing the treatment’s impacts requires coordination between human and veterinary health practitioners.