Health officials say as many as 200 participants in the Test of Metal in Squamish have reported getting sick after the June 16 mountain bike race.

Shortly after the race 18 people reported gastrointestinal symptoms.

'A couple of hundred of them have told us that they were ill after the race.' —Dr. Eleni Galanis

A followup survey has found the number of affected people may be 10 times higher.

The Test of Metal, held every year in Squamish, north of Vancouver, is one of the biggest mountain bike races in North America. About 800 people took part in the race this year.

The B.C. Centre for Disease Control sent out a survey last Friday to all 800 participants to see if there were more victims, and to try to pinpoint the source of the illness.

"To date about 300 to 400 people have responded to the survey, and a couple of hundred of them have told us that they were ill after the race," Dr. Eleni Galanis said.

So far the centre has not yet pinpointed the source of the bacteria, but Dr. Paul Martiquet, the medical health officer for the Squamish region, says the most likely scenario is that the riders ingested muddy water infected with campylobacter bacteria.
 
"All of the people who've been sick were either riders or spectators. No one from the community or surrounding area has reported symptoms," said Martiquet.

"The mud would get on their water bottles, on fruit that they picked up along the course, and before they could get it into their mouths, which were surrounded by mud, the fruit would get mud on it," said Martiquet.

"So what we're doing is looking at the … mud that was on the course and determining if it had campylobacter bacteria in it."

Martiquet says manure in a horse-riding area along the course is being tested. The centre for disease control expects to release its preliminary report next week.

A statement from the centre says campylobacter is a common cause of diarrhea in B.C., and throughout the world. Those who become infected may also experience nausea, stomach pain, fever and vomiting for anywhere between two and seven days. Sometimes a person can be infected and have no symptoms.

"You can protect yourself and your family from infection by ensuring that you wash your hands thoroughly before eating, when handling food, after using the toilet and after touching animals," said Martiquet. "And it's never a good idea to drink untreated water from creeks or streams."