Canadian Bacterial Diseases Network - CBDN

CBDN researchers bring E. coli vaccine closer to market

The deadly E. coli O157:H7 is making headlines again, but this time the news is good. A year after the Walkerton tragedy, there is hope that Canadian farmers will soon be able to vaccinate their cattle against the bacteria with a new Canadian-developed vaccine, saving millions of dollars and, potentially, human lives.

The vaccine – made possible by the work of Dr. Brett Finlay, a University of British Columbia researcher funded by the Canadian Bacterial Diseases Network (CBDN) – will become an important management tool in the cattle industry's crusade against the hazardous E. coli bacteria.

Researchers have completed small trials on the vaccine. The results look promising, and they hope to begin large-scale trials in the fall of 2001.

"Cattle feaces seeping into water and the slaughter of infected animals are considered to be the primary sources of E. coli infection in humans," explains Dr. Finlay. Because the E. coli bacterium does not usually cause disease in animals, up to 50 per cent of livestock carry the organism at some stage during their life.

"An E. coli vaccine is the best solution, because it deals with the problem at the source," Dr. Finlay says. "Preventing the E. coli colonization in cattle will indirectly reduce the risk of E. coli infection in humans."

The vaccine reduces the number of organisms in cattle and cattle manure, which in turn reduces the risk of contaminating food and water. Dr. Finlay isolated the bacterial components that allowed scientists to produce the vaccine.

"Because these bacterial components stimulate the production of antibodies, we were able to use them to formulate a vaccine," says Dr. Finlay. Together with Dr. Andrew Potter, an expert in veterinary vaccinology at Veterinary Infectious Disease Organization (VIDO) in Saskatoon, Dr. Finlay demonstrated that the vaccination of cattle with these antigens reduces the level of E. coli.

The market potential and direct economic benefits of the vaccine are enormous. In Canada, annual cattle production is estimated to be 14 million heads, and the indirect contribution to an annual beef export market is more than $1.6 billion.

"But the major impact of an E.coli vaccine is on human health," says Dr. Finlay, "both in Canada and internationally, as the safety of the food we eat has become a major health concern."

E. coli infection is a destructive disease with no known specific treatment that can cause kidney damage, which can result in death especially in children and the elderly. Although commonly a part of the normal intestinal flora, the bacterium's virulent strain, designated O157:H7, causes intestinal infection in humans. The infection is often acquired through contaminated food products such as under-cooked beef and tainted fruits and vegetables.

The bacteria are an emerging cause of diarrhea in the developed world, with 10,000 to 20,000 cases reported annually in the United States. Canadians are familiar with E. coli O157:H7 because of the last year's Walkerton tragedy in which 7 people lost their lives and more than 2,000 became ill.

CBDN, a member of the federal Networks of Centres of Excellence program, is a Canada-wide consortium of researchers and their laboratories whose work focuses on bacterial disease. CBDN's mission is to advance scientific knowledge and enhance Canada's economic competitiveness through networking, excellence in fundamental research on bacterial diseases, and collaboration with industry.

CBDN is one of 20 federally funded Networks of Centres of Excellence, the objectives of which are to enhance the Canadian economy and our quality of life. The program is funded by the Natural Sciences and Engineering Research Council (NSERC), the Canadian Institutes of Health Research (CIHR) and the Social Sciences and Humanities Research Council (SSHRC), in partnership with Industry Canada.

For more information about the Canadian Bacterial Diseases Network, visit www.cbdn.ca.