A new version of a common intestinal bug is becoming more deadly and more easily transmitted, and Triangle medical professionals are at the forefront of the study.

Although medical workers have known the bacterium Clostidium difficile as a cause of diarrhea in hospitals and in people taking antibiotics, the Centers for Disease Control have put it under national surveillance for increased virulence.

While both humans and animals carry the bug, the animal strains have not seen a parallel increase in virulence.

According to David Damsker, community health lead physician of the Wake County Health Department, C. difficile is part of the “normal flora” of the intestinal tract. He said that when patients take antibiotics, they kill the other bacteria, allowing C. difficile to thrive.

“It’s not like this is some weird bacteria that we don’t know where it comes from,” he said. “The problem is that there have been outbreaks of higher mortality strains, and cases in people who haven’t taken antibiotics.”

Recent concern about the changing pathology of C. difficile is based on years of data, some of which comes from the Durham VA Medical Center. The disease is no more common in North Carolina than in any other state, but the VA center’s unusually thorough record-keeping has allowed the state to play a central role in the national study.

f0 “There are anecdotal reports that the disease has spread, but it’s hard to follow because it’s not mandatory for hospitals to report C. difficile,” state epidemiologist Jeffrey Engel said. “But the VA hospital in Durham has been keeping a database that suggests that incidences of this disease are on the rise.”

f0 Following up on medical records in the database could also suggest new risk factors that predict who could get the disease.

“Traditionally, being in a hospital or having taken antibiotics in the last 90 days were the major factors,” Engel said. “Now, being female, being pregnant and taking acid reduction drugs like Pepsid AC or the Purple Pill [Nexium] are all possible factors, but none of them has been confirmed yet.”

Engel said what caused the new strain to develop is unclear.

“We don’t know why this new strain emerged,” Engel said. “Bugs are very adept at mutating, and it could be that after a random mutation a bug simply finds itself easier to transmit and increases, not necessarily due to any new pressure exerted by humans, like antibiotic use.”

For the time being, the new disease is nothing for students to be worried about, according to health officials.

f0 “I don’t want there to be a panic here,” Damsker said. “There have been outbreaks in specific areas, and isolated incidents, but nothing is certain yet. This new study is happening just because it’s important to know how the epidemiology of this bacterium is emerging.”

The best way to avoid the disease, he added, is to stay out of the traditional risk groups.

f0 “For students, simply limiting antibiotic use is the most important factor,” Damsker said. “Don’t take antibiotics unless it’s really necessary.”

While Duke University is involved in the study of C. difficile as a human pathogen, N.C. State students and professors see the bacterium in a different context: veterinary medicine.

While humans are affected by different strains of the bacteria, the disease can follow similar patterns for pigs.

“C. difficile is not that common in pigs unless they have a pre-existing condition,” Glen Almond, professor of population health and pathology, said. “We only see it in baby pigs or ones that are on antibiotic therapy.”

Still, in a state that is home to more pigs than people and where hog farming is over a $1 billion industry, C. difficile matters.

f0 “The disease isn’t fatal. Animals will recover, but it causes what we call fallback pigs, ones that don’t grow as fast as their littermates,” said Karen Post, assistant director of Rollins Animal Disease Diagnostic Laboratory in Raleigh. “This is where you see the economic impact for hog farmers.”

Strains of the bacteria also turn up as causes of diarrhea in foals, adult horses and in hamsters, Post said.

However, there is no need for veterinary students to worry about their personal safety.

“One of the things we get tired of in the pork industry is people pointing fingers, saying a disease moved from pigs to humans,” Almond said. “Really, we’re more concerned about it going the other way. Farm workers and vets are in contact with pigs all the time, and they don’t ever get C. difficile from the animals.”

While animal strains of C. difficile can colonize human intestines, they do not cause disease in humans. Nor is there evidence that they have become more virulent or deadly in recent years.

“Many antibiotics used in human medicine are not used in veterinary medicine,” Post said. “I would suspect that there is not as much selection pressure favoring a more virulent strain in pigs as there is in humans.”