ISU Study Finds E. Coli O157:H7 in Swine

May 28, 2008 — 

E. coli O157:H7, an organism that causes gastrointestinal disease in humans, is generally associated with cattle, but it can also be recovered from swine to a lesser extent.

Recent research at Iowa State University revealed that the pathogen can be transmitted through the air among swine, even in the absence of direct contact. Nancy Cornick, an ISU associate professor of veterinary microbiology who has researched the issue for the Food Safety Consortium, has previously shown that uninfected pigs sharing pens with infected pigs could also become infected. In the more recent research, it appeared that transmission of the organism could be accomplished through the air even when infected pigs were separated from uninfected pigs.

Other experiments have also shown that E. coli O157:H7 can establish and maintain a population in some pigs' intestinal tracts for at least two months, indicating that the bacterium can colonize swine. The incidence of the pathogen in swine remains small but worthy of notice. Cornick noted that one U.S. slaughter facility recovered E. coli O157:H7 in 2 percent of its pigs, and the bacterium has also been recovered from healthy swine in Japan, Chile, the Netherlands, Norway and Sweden.

Cornick seeks to follow up the swine research by performing the same experiments with cattle, which are considered the major reservoir of E. coli O157:H7.

[Ed. Note: It is not known if the bacterium is capable of spreading from pig to pig under normal field conditions. The USDA's National Animal Health Monitoring Surveys (NAHMS) conducted in 1995, 2000 and 2006 tested 8660 fecal samples collected from 343 randomly selected swine farms for the presence of virulent E. coli O157:H7. All samples were negative. Some small-scale studies, however, have shown a very low prevalence of O157:H7 in U.S. pigs. Standard processing techniques and proper handling during storage and preparation will prevent contamination of pork products. The USDA's Food Safety and Inspection Service (FSIS) recommends cooking pork steaks, chops and roasts to 145°F and ground pork to 160°F. Humans infected with shiga-toxin producing E. coli may develop severe stomach cramps, diarrhea (often bloody) and vomiting. Five to ten percent may progress to a potentially life-threatening complication known as hemolytic uremic syndrome.]

Sources:
University of Arkansas, Food Safety Consortium, May 20, 2008

National Pork Board