Mountain Bike Racers Likely Got Food Poisoning From Contaminated Mud in B.C.

By Helen Branswell, Medical Reporter, THE CANADIAN PRESS

If you didn’t have enough reasons to think eating mud is a bad idea, here is another: Mountain bike racers who became ill after a meet in British Columbia last June probably contracted the bug that sickened them from feces in the mud they biked through, researchers reported Monday.

Over a quarter of the nearly 800 participants fell ill in what public health officials believe is one of the biggest reported outbreaks in this country of Campylobacter jejuni – a diarrhea-causing bacteria that is generally contracted through consumption of contaminated food or water.

When it became apparent bikers who took part in the race had fallen victim to a nasty stomach bug, organizers, local medical authorities and participants themselves were quick to question whether mud might have been to blame.

The course was apparently so muddy on the day of the race that competitors had to dismount and push their bikes through some spots.

“All you could see were the whites of their eyes from the pictures we saw,” Dr. Eleni Galanis said of the riders.

“There was a lot of mud flying.”

Findings of the investigation into the outbreak were presented Monday at the International Conference on Emerging Infectious Diseases in Atlanta.

Investigators from the Public Health Agency of Canada’s field epidemiology program, the British Columbia Centre for Disease Control and Vancouver Coastal Health Authority conducted the investigation.

Campylobacter is believed to cause between five and 14 per cent of reported cases of diarrhea globally, according to the Public Health Agency of Canada. Most cases, though, are one-offs; large clusters of cases are rare, the website of the U.S. Centers for Disease Control says. Symptoms can last for between two and 10 days.

The diarrhea is often accompanied by abdominal cramps that are so severe some sufferers mistake them for appendicitis, Galanis, a physician epidemiologist at the B.C. CDC and the senior author on this work, said from Vancouver.

The race was held in Squamish, half-way between Vancouver and Whistler.

When investigators tried to figure out what had happened, results of a web-based survey of participants suggested the exposure may have occurred in the latter half of the 67 kilometre course.

They sampled mud puddles along the route, but they didn’t find any evidence of Campylobacter. That may not be too surprising – the sampling took place three weeks after race day.

They did find high counts of coliforms – a term used to describe a variety of bacteria that are found in feces – as well as evidence of E. coli contamination. Galanis said the investigators still haven’t been able to pinpoint the source of the fecal contamination or the species (human or non-human) that produced it.

“What is that? We still don’t know,” she said.

The drinking water racers were given along the course was tested and ruled out as a possible source of infection.

Galanis said the investigators could find no references in medical journals of similar outbreaks but in discussing the case with colleagues have learned of three other such outbreaks, one in British Columbia, one in the U.S. and one in Europe.

They hope to publish their findings in the hopes of alerting future race organizers and racers themselves that muddy courses could pose an unexpected health risk to participants.

“Will it happen again? It’s possible. You’d have to have the same set of circumstances at the same time,” Galanis said.