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# Study: Lawsonia May Cause Pigs to Shed More Salmonella
- URL: https://www.foodsafetynews.com/2015/11/study-lawsonia-intracellularis-may-cause-pigs-to-shed-more-salmonella/
- Published: 2015-11-06T06:01:21.000Z
- Updated: 2018-07-31T07:49:55.000Z
- Author: Lydia Zuraw
- Tags: Science & Research, food safety, Lawsonia intracellularis, pigs, pork, Richard Isaacson, Salmonella, University of Minnesota, #wp, #wp-post, #Import 2025-11-25 10:59

[![scaredpig_406x250](http://foodsafetynewsfullservice.marlersites.com/files/2015/11/scaredpig_406x250.jpg)](http://foodsafetynewsfullservice.marlersites.com/files/2015/11/scaredpig%5F406x250-1.jpg?ref=foodsafetynews.com)

Earlier this year, at least [152 people](http://www.cdc.gov/salmonella/pork-08-15/index.html?ref=foodsafetynews.com) in Washington state were infected with multidrug-resistant *Salmonella* I 4,\[5\],12:i:- linked to pork produced by Kapowsin Meats. According to [federal estimates](https://www.foodsafetynews.com/federal-agencies-develop-foodborne-illness-attribution-method/), pork is the source of about 8 percent of *Salmonella* illnesses in the U.S. Scientists interested in finding ways to control *Salmonella* in pigs first want to know what might predispose the animals to carry the pathogen and cause them shed higher levels of it. Researchers at the University of Minnesota’s Department of Veterinary and Biomedical Sciences are looking into the connections between *Salmonella* and *Lawsonia intracellularis,* the cause of a common diarrheal disease in pigs called porcine proliferative enteritis. In the first part of their study, Minnesota professor Richard Isaacson and his colleagues experimentally challenged pigs with *Lawsonia*, *Salmonella*, or both, and followed their secretion of *Salmonella* over time. What they found was that the animals infected with both pathogens had higher levels of *Salmonella* in their feces and over a longer period of time. “It suggested to us that *Lawsonia* predisposes to this higher-level shedding and may cause what we’d like to call a ‘supershedder,’” Isaacson told **Food Safety News**. People have found [supershedders of *E. coli O157*](https://www.foodsafetynews.com/e-coli-cattle-vaccination-could-prevent-83-percent-of-human-cases/) in cattle, but “people have looked for that in *Salmonella* and never has anyone actually been able to identify it as far as I’m aware,” he added. The second part of the Minnesota study, which was [published](http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0139106&ref=foodsafetynews.com) last month in the journal PLOS One, tracked changes in the microflora — the community of microorganisms living in the digestive tract — found in the pigs’ feces. “People have said for a long time that normal flora of animals and people help protect us against pathogens coming in,” Isaacson said. His team wanted to find out whether or not that was actually true. And the answer, according to their study, was that it’s not. Both *Lawsonia* and *Salmonella* cause substantial changes to the composition of that microflora, and each one caused somewhat different changes, Isaacson explained. The researchers are now looking at how those changes might cause increased shedding of *Salmonella*. In a further research that has just begun, the scientists aim to find out whether vaccinating pigs for *Lawsonia* would protect them from shedding *Salmonella*. (To sign up for a free subscription to **Food Safety News**, click [here](http://www.foodsafetynews.com/subscribe/#.VcL0VsZNPVs).)