Image: Eco-Challenge 2000
In addition to 12 days of jungle trekking, sailing, paddling, canyoneering, scuba diving, mountain biking and caving, competitors in this year's Eco-Challenge 2000 around Borneo faced another daunting event when they got back home: surviving leptospirosis. Scientists from the Centers for Disease Control and Prevention (CDC) recently discovered through a survey that at least 25 percent of the participants eventually developed the disease, which causes flu-like symptoms, vomiting and diarrhea and sometimes serious damage to the liver, kidneys and lungs. They announced the finding at the annual meeting of the American Society of Tropical Medicine and Hygiene.

The scientists first suspected the link between the race and the disease when the CDC received word of isolated cases in Idaho, San Diego and Los Angeles. It turned out that in each instance, the patient had just finished the Eco-Challenge. "Based on those initial results, we initiated a telephone survey," says Jim Sejvar at the CDC. "Through a collaborative effort we tried to reach as many of the participants as possible, gather information on any illness or symptoms they had experienced and identify risk factors associated with illness."

They eventually made contact with just under half of the 308 racers in their survey and found that nearly half of them--around 44 percent--experienced symptoms common to leptospirosis infection. "Several of the events, including kayaking, swimming in the river and spelunking, appeared to be risk factors for infection," Sejvar adds. "The only independently significant risk factor, though, was swimming in the river. There were a number of participants who became ill who did not report swimming in the river, but it's possible they were exposed to the river water during one of the other events." In fact, leptospirosis is caused by a bacterium often transmitted to humans through water contaminated with urine from infected animals. And it has been known to strike other adventure travelers. At the same meeting researchers from the University of Utah reported on a woman who developed leptospirosis after a two-week kayaking trip in Ecuador.

The scientists first suspected the link between the race and the disease when the CDC received word of isolated cases in Idaho, San Diego and Los Angeles. It turned out that in each instance, the patient had just finished the Eco-Challenge. "Based on those initial results, we initiated a telephone survey," says Jim Sejvar at the CDC. "Through a collaborative effort we tried to reach as many of the participants as possible, gather information on any illness or symptoms they had experienced and identify risk factors associated with illness."

They eventually made contact with just under half of the 308 racers in their survey and found that nearly half of them--around 44 percent--experienced symptoms common to leptospirosis infection. "Several of the events, including kayaking, swimming in the river and spelunking, appeared to be risk factors for infection," Sejvar adds. "The only independently significant risk factor, though, was swimming in the river. There were a number of participants who became ill who did not report swimming in the river, but it's possible they were exposed to the river water during one of the other events." In fact, leptospirosis is caused by a bacterium often transmitted to humans through water contaminated with urine from infected animals. And it has been known to strike other adventure travelers. At the same meeting researchers from the University of Utah reported on a woman who developed leptospirosis after a two-week kayaking trip in Ecuador.