Parasites, viruses and bacteria in the Oklahoma River were to blame for sickening dozens of participants in an international triathlon held last month, state health officials said Wednesday.
At least 45 participants in the Boathouse International Triathlon in Oklahoma City became sick with gastrointestinal problems after the event held May 16-17.
The Oklahoma State Department of Health said the illness was related to exposure to water during swimming practice sessions or during the swim portion of the event.
"Laboratory analyses of stool specimens from a few ill athletes were positive for different gastrointestinal agents, including norovirus, and a couple of different kinds of bacteria and parasites, all of which are compatible with this gastrointestinal outbreak and which could be associated with exposure to water contaminated with human or animal waste," the department said in a statement.
Athletes swam 1.5 kilometers in a downtown portion of the river as part of the triathlon. After the event, some of the participants reported diarrhea, vomiting, abdominal cramping and fever.
The river has tested high for bacteria, particularly after high runoff from storms.
There were 367 participants in the triathlon, which was held after a heavy rain. A total of 218 responded to a health department survey and of that number, 45 reported symptoms.
Debbie Ragan, a spokeswoman for Oklahoma City's utilities department, has said water samples taken on May 15 near the swim course showed an E. coli count of 573 per 100 milliliters of water. The Oklahoma Water Resources Board said standards for "primary body contact recreation," in which there is a chance water could be ingested, is a 126 count for E. coli.
The river, formerly a ditch that handled runoff, has been transformed in recent years into a prime venue for rowing events, but this was the first time a triathlon had been held there.
"The amount of time spent swimming in the river during the practice sessions and during the event is the only significant exposure associated with the development of diarrheal illness among participants," said Lauri Smithee, chief of the health department's acute disease service.
Mike Knopp, the director of the Oklahoma City Boathouse Foundation, which helped organize the event, said the disease outbreak was unfortunate.
"This is a one-time incident that is specific to triathlon, and event organizers will take every precaution to make sure it doesn't happen again," he said in a statement.
The state Health Department said a working group of several state and local agencies will study the event to learn how such problems can be avoided in the future.
In an Associated Press story before the triathlon, Derek Smithee, the water quality division chief of the Oklahoma Water Resources Board, said a six-mile section of the river near downtown is listed by the state as "impaired" because of fecal coliform, sulfates and turbidity.
But he also said this listing didn't mean the water wasn't safe for swimming.
"It's probably more dangerous to drive to the Oklahoma River than to swim in the Oklahoma River," Smithee said at the time.
Oklahoma City water quality officials began testing the river's quality about six months before the triathlon, at the request of race organizers. Bret Sholar, the race director, said he made the final call to conduct the triathlon and said the bacterial levels were only one consideration.
He said he spoke with representatives from the city and the International Triathlon Union the morning of the event. He said the river's flow was down, as was the level of debris in the river, and he believed bacterial levels in the river were falling as well.
"We've just learned that there is always a risk in triathlons, especially when you swim in open water," Sholar said.
"We can't have control over the river. Hopefully the athletes understand that an open water swim has an associated risk."
He said plans call for the triathlon to be held again next year.
Skylar McElhaney, a spokeswoman for the Oklahoma Department of Environmental Quality, said that agency has no statutory authority to shut down a body of water and does not issue swimming advisories specific to a body of water.
"Anytime you swim in a natural body of water you run the risk of being exposed to harmful bacteria," McElhaney said.