Research team links illness to pigs raised without antibiotics

Columbus, Ohio

- A new study conducted by The Ohio State University College of Veterinary Medicine suggests that pigs raised without antibiotics were more susceptible to parasitic infections and disease.

In a comparison of antibiotic-free pigs and conventionally raised pigs, more than half of the antibiotic-free ones in the study tested positive for Salmonella, compared to 39 percent of the conventional livestock. The Toxoplasma gondii parasite was found in 6.8 percent of the antibiotic-free stock, compared to 1.1 percent of the conventional livestock. Two antibiotic-free pigs out of the 616 total tested also were positive for Trichinella spiralis, a rare parasite that can be fatal to humans who consume undercooked meat. It was considered to be eradicated from U.S. pork operations.

Lead study author Wondwossen Gebreyes, associate professor of veterinary preventative medicine at OSU, says none of the bacteria and parasites found in the pigs should pose problems if the meat is cooked thoroughly. He would not recommend one method of raising pigs over another based on the study, saying he was merely studying the difference in environments.

"We are just doing the research and showing the results," Gebreyes says. "Does having an antibiotic-free and animal-friendly environment cause the re-emergence of historically significant pathogens? I think that is an extremely important question for consumers, policymakers and researchers to consider."

Naturally raised pigs' exposure to moisture, vegetation and other animals in their free-range environment could add to the higher instance of common bacteria, the study adds.

The study was funded by a grant from the National Pork Board and was co-authored by Peter Bahnson of the University of Wisconsin School of Veterinary Medicine, Julie Funk and James McKean of the College of Veterinary Medicine at Iowa State University, and Prapas Patchanee of the OSU Department of Veterinary Preventative Medicine. The entire study is published in the journal of Foodborne Pathogens and Disease.