They say it is fatal in about 1 percent of cases. An investigation by the Centers for Disease Control and Prevention has focused on two events. The are the Springfield, Ill., Ironhorse Triathlon, in which about 966 people participated on June 21, and the 1998 Bally Total Fitness USTS Madison, Wis., Triathlon on July 5, which had about 850 participants, authorities said. Athletes came from at least 44 states to attend the events. Participants who become ill with fever should contact their healthcare provider to receive appropriate care in case they have the disease, the CDC said.
Leptospirosis is caused by a microorganism spread by infected animals, especially rodents or dogs.
The CDC said symptoms four to 19 days after exposure include fever, chills, headache and sometimes a rash. Infectious disease specialists were continuing to contact others of the 966 people who participated in the Springfield Ironhorse Triathlon. In Wisconsin Sunday, Jeff Davis, a state epidemiologist, said health officials tried to continue to interview Wisconsin residents who participated in one or both of the events and do blood and urine tests on them. The tests could help to determine if sick participants actually have leptospirosis, Davis said. In the meantime, Illinois officials say swimmers, water skiers and jet skiers should avoid a portion Lake Springfield extending from the Interstate 55 bridge southwest past the Bridgeview Park area in the Sugar Creek arm of the lake.