Leptospirosis in “Eco-Challenge” Athletes, Malaysian Borneo, 2000

Abstract

Adventure travel is becoming more popular, increasing the likelihood of contact with unusual pathogens.We investigated an outbreak of leptospirosis in "Eco-Challenge" multisport race athletes to determine illness etiology and implement public health measures.Of 304 athletes, we contacted 189 (62%) from the United States and 26 other countries.Eighty (42%) athletes met our case definition.Twentynine (36%) case-patients were hospitalized; none died.Logistic regression showed swimming in the Segama River (relative risk [RR]=2.0;95% confidence interval [CI]=1.3 to 3.1) to be an independent risk factor.Twenty-six (68%) of 38 case-patients tested positive for leptospiral antibodies.Taking doxycycline before or during the race was protective (RR=0.4,95% CI=0.2 to 1.2) for the 20 athletes who reported using it.Increased adventure travel may lead to more frequent exposure to leptospires, and preexposure chemoprophylaxis for leptospirosis (200 mg oral doxycycline/ week) may decrease illness risk.Efforts are needed to inform adventure travel participants of unique infections such as leptospirosis. E ach year, 60 million Americans travel abroad.Increasingly, these persons are traveling to more remote and exotic destinations.Adventure travel is now the largest growing segment of the leisure travel industry, with a growth rate of 10% per year since 1985 (Adventure Travel Society, pers.comm.).This travel has led to an increasing risk for contact with pathogens uncommon in industrialized countries, especially for participants in adventure sports and extreme travel.Both of these pursuits may predispose persons to infection with unusual organisms through exposures to lakes, rivers, caves, and canyons, as well as insect vectors.These illnesses may be unfamiliar to practitioners in the travelers' home countries, and symptoms may go unrecognized.Leptospirosis, a bacterial zoonotic infection, is more frequently found in developing countries, and its protean early symptoms may be difficult to diagnose clinically.Prevention of leptospirosis in humans has previously relied on mechanical barriers and avoidance (1), but limited published data suggest that preexposure chemoprophylaxis may be beneficial to some groups (2-4).From September 7 to September 11, 2000, the Idaho Department of Health, the Los Angeles County Department of Health Services, and the GeoSentinel Network (an international surveillance network of travel clinics) notified the Centers for Disease Control and Prevention (CDC) of at least 20 cases of febrile illness.The illness was characterized by the acute onset of high fever, chills, headache, and myalgias; major laboratory test abnormalities and important pulmonary or central nervous system involvement were absent.All ill persons had participated in the Eco-Challenge-Sabah 2000 multisport endurance race, held in Malaysian Borneo August 21-September 1, 2000.Three hundred four athletes from 26 countries and 29 U.S. states competed in the 10-day endurance event.Segments of the event included jungle trekking, prolonged swimming and kayaking (both in fresh and ocean water), spelunking (caving), climbing, and mountain biking.Symptoms and exposure history, as well as initial laboratory testing, suggested that the illness was leptospirosis.We undertook an investigation to determine the etiology of the illness in the athletes and to make public health recommendations.We report on the results of this investigation and discuss recommendations for preventing leptospirosis in adventure travelers. Methods Epidemiologic InvestigationUpon identification of the first ill athletes, a complete list of U.S. and international participants in the Eco-702