A study team of five headed by Dr. Scott Weese at Ontario Veterinary College, University of Guelph, calls the discovery “remarkable” in a paper published in August in the Anaerobe scientific journal.
They found that most hogs will be free of the bacteria when they go to market, even if they had it when they were newborn piglets.
Weese has published other papers about Clostridium difficile, trying to determine how much of a threat hogs and pork pose to people. While he has found plenty of the bacteria on hog farms, he has always cautioned that more research is required.
This study involved 10 sows that were tested before they farrowed; four had Clostridium difficile.
When the piglets were two days old, 90 of the 121 were infected. One surprise is that more of those infected were from sows that tested free of the bacteria prior to farrowing. However, when they were tested again on day seven, most of the 66 that still had the bacteria were from the four sows that had tested positive.
By day 30, only 40 per cent of the piglets tested positive, by day 44 only 23 per cent and by day 62, only 3.7 per cent.
There is no explanation in the paper about why 40 per cent of the sows, which are mature beyond market weight, tested positive.
The second most common strain of Clostridium difficile they identified in the pigs is a toxin-producing one that harms people. Fully 97 per cent of the strains identified in the pigs have also been identified in humans.
Clostridium difficile has recently emerged as a cause of serious diarrheal infections among elderly and immunocompromised patients in hospitals and long-term care facilities. Sometimes it develops into more serious problems, such as colitis.
People are warned not to touch their mouth or eyes after they touch any surface contaminated with human feces and healthcare workers need to clean their hands to keep from spreading the bacteria to their patients.
People who work with pigs should likely be similarly cautious to thoroughly clean their hands and to avoid touching their mouths and eyes.
