The University of Glasgow reported today:
Vaccinating cattle against the E. coli O157 bacterium could cut the number of human cases of the disease by 85%, according to scientists.
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. Cattle are the main reservoir for the bacterium.
The vaccines that are available for cattle are rarely used, but could be significant.
The research was lead by a team of researchers at the University of Glasgow in collaboration with the University of Edinburgh, the Royal Veterinary College, Scotland’s Rural College, Health Protection Scotland, and the Scottish E. coli O157/VTEC Reference Laboratory.
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 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.
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.
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 programme of vaccination. In addition, research is continuing in Scotland by the same collaborative grouping to develop even more effective vaccines that would further reduce the impact on human disease.
Lead author, Dr Louise Matthews, Senior Research Fellow in the Institute of Biodiversity, Animal Health and Comparative Medicine, said: “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.
“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 programme, the public health justification must be taken seriously.”
In Scotland, an average of 235 culture positive cases of E. coli O157 infection per year (i.e. people who had the organism in their stools) were notified to Health Protection Scotland from 2008 to 2012.
The vaccines that are available currently have poor take-up: one version in the US is not fully licensed because medicines for veterinary use must show that animal health is improved. This is problematic because E. coli O157 does not harm cattle and assessing the impact of treatment involves coordination between human and veterinary health practitioners.
Senior author Professor Stuart Reid of the Royal Veterinary College added: “We increasingly recognise the fact that we share a common environment with the animals we keep – and inevitably the pathogens they harbour. This study is an excellent example the interface between veterinary and human medicine and of the concept of ‘One Health’ in action – controlling infections in animals can have a major impact on public health.”
One year ago Kansas State reported:
A commercial vaccine for cattle can effectively reduce levels of E. coli by more than 50 percent, a Kansas State University study has found. The vaccine is also effective using two doses instead of the recommended three doses, which can help cut costs for the beef industry.
David Renter, associate professor of epidemiology, is the principal investigator on a project that researched the effectiveness of products used to prevent the shedding of E. coli O157:H7 in cattle. The research appears in a recent online version of the journal Vaccine and helps improve current preventative methods for addressing food safety concerns.
While E. coli O157:H7 does not affect cattle, it causes foodborne disease in humans. Vaccines and other products may be given to cattle to help prevent the spread of the bacteria.
“We wanted to test how well these products work to control E. coli O157:H7 in a commercial feedlot with a large population of cattle that were fed in the summer and may be expected to have a high level of E. coli O157:H7,” Renter said.
Other Kansas State University researchers involved include T.G. Nagaraja, university distinguished professor of microbiology; Nora Bello, assistant professor of statistics; Charley Cull, doctoral student in pathobiology, Oakland, Neb.; and Zachary Paddock, doctoral student in pathobiology, Manhattan, Kan. Abram Babcock, an August 2010 Kansas State University doctoral graduate, also was involved in the research.
Using a commercial feedlot setting, the researchers studied more than 17,000 cattle during an 85-day period. They studied two products: a vaccine and a low-dose direct-fed microbial.
“What’s unique about this study is the number of animals we used, the research setting and that we used commercial products in the way that any cattle producer could use them,” Renter said. “We didn’t want it to be any different than the way somebody would use the products in a commercial feedlot.”
The researchers found that the vaccine reduced the number of cattle that were shedding E. coli O157:H7 in feces by more than 50 percent. E. coli shedding was reduced by more than 75 percent among cattle that were high shedders of E. coli. While the vaccine label suggests that it is given in three doses, the researchers found that two doses of the vaccine significantly reduced E. coli.
“Showing that level of efficacy with two doses is really important because a shift to two doses from three could significantly cut costs for the beef industry,” Renter said. “In terms of logistics, it can be difficult for commercial feedlot production systems to vaccinate animals three times. Both of these benefits help when considering how the vaccine can be adopted and implemented in the industry.”
The researchers also discovered that the low-dose direct-fed microbial product did not work as well as the vaccine. Renter said while the study used a lower dose of the direct-fed microbial and could find no evidence that it reduced E. coli shredding, it is possible that the direct-fed microbial product is more effective at a higher dose.
“This vaccine is an option for reducing E. coli,” Renter said. “We have shown that this vaccine works and that it is a tool that could be adopted in the industry.”