Dairy Channel: On-farm dairy study of E. coli 0157


I have agreed to help Jeffrey T. LeJeune, DVM, assistant professor in the Food Animal Health Research Program at the Ohio Agricultural Research and Development Center on a field research project in Northeast Ohio.

The research, designed to assess the prevalence of E. coli 0157 on farms in the United States and Norway, involves culturing bacteria from rectal swabs of dairy cattle to determine whether E. coli 0157 is present.

Data will be used to determine the prevalence of the bacterium, and whether it’s incidence is related to herd size, type of housing, source of water and method of watering cattle or source of feed for the herd (purchased vs. home grown).

I’ll be sampling nine herds ranging from 30-500 cows in Columbiana and Mahoning counties and forwarding samples to Wooster, Ohio, for analysis. The following information is provided by LeJeune about E. coli 0157:

By LeJeune. Escherichia coli 0157 is a specific type of bacterium sometimes found in the digestive tract of cattle and in cattle manure. It produces several powerful toxins (Shiga toxins). This bacterium does not cause disease in cattle or calves as several other types of coliform bacteria do (such as Klebsiella 99 and 88), but it can cause severe illness or death in humans.

Usually, infection in humans results from the accidental ingestion of the bacterium after direct contact with animals or in contaminated foods or water.

Most cases of E. coli 0157 in humans can be traced, either directly or indirectly to cattle. The consumption of improperly handled or inadequately cooked foods of bovine origin, including beef and unpasteurized dairy products, are the primary sources of infection.

Increasing outbreak. Recently, an increasing number of outbreaks of E. coli 0157 have been attributed to water contamination and the consumption of raw vegetables (both of which may be contaminated with bovine manure). Several large outbreaks have also been linked to inadequate hand washing by children after visiting farms or petting zoos.

E. coli 0157 can cause a variety of diseases ranging from diarrhea to a serious disease known as Hemolytic Uremic Syndrome. It causes an estimated 80,000 cases of human illness each year in the United States.

About 500 people, mostly children, die as a result of these infections each year in the United States. Children who survive Hemolytic Uremic Syndrome often need kidney transplants or life-long kidney dialysis.

What it means. The occurrence of E. coli 0157 in cattle and manure has three direct implication for farmers:

* Farmers that ingest even microscopic amounts of the bacterium directly or in unpasteurized milk may become seriously ill.

* Visitors and guests at farms may become infected in the same manner.

* Cull cattle harboring this organism in their digestive tract or on their hides at the time of slaughter pose a safety risk to the food supply.

There are no visible signs that an animal has E. coli 0157. It does not make cattle ill. Animals of all ages may become infected, but it is more commonly found in 3- to 18-month-old heifers.

It is found in cattle on most farms at one time or another, most frequently in the summer. It can also be found contaminating feed bunks, water troughs and other environmental reservoirs such as gates and walkways on farms where it may persist for extended periods.

Protection. There are a couple ways farmers can protect themselves, their employees and their guests from this deadly bacterium:

* Make sure all people who visit animal contact areas wash their hands thoroughly afterward.

* Make sure you, your family and your employees do not eat uncooked or undercooked meat or unpasteurized milk from your bulk tank.

Controlling the prevalence and magnitude of E. coli 0157 populations in cattle in order to enhance food safety is more complicated. To date there are no known effective control measures for E. coli 0157 in cattle. Current research is investigating feed and water hygiene, dietary supplements for cattle and vaccination.

Back to Ernie. I will be visiting nine herds in the area, taking rectal swabs of 15 cows in each herd. I will take every precaution to prevent the carrying of E. coli 0157 or any other pathogen from one herd to another during these visits.

We sincerely appreciate your cooperation and support of this research.

(The author is an agricultural extension agent in Columbiana County. Questions or comments can be sent in care of Farm and Dairy, P.O. Box 38, Salem, OH 44460.)


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