Skip Navigation LinksSkip Navigation Links
Centers for Disease Control and Prevention
Safer Healthier People
Blue White
Blue White
bottom curve
CDC Home Search Health Topics A-Z spacer spacer
Blue curve MMWR spacer

Public Health Dispatch: Outbreak of Acute Febrile Illness Among Participants in EcoChallenge Sabah 2000 Malaysia, 2000

On September 7, 2000, CDC was notified by Idaho Department of Health about a case of acute febrile illness in a 35-year-old man; the illness was characterized by acute onset of high fever, chills, headache, and myalgias. The patient had participated in the EcoChallenge Sabah 2000 Expedition Race, a multisport event held during August 20September 3, at various sites in Sabah in Malaysian Borneo.

This report presents preliminary findings of an ongoing investigation to identify cases of acute febrile illness among athletes who participated in the EcoChallenge Race in Borneo during August 2000. Preliminary laboratory test results indicate the probable cause of illness to be leptospirosis, a spirochete infection. The event involved jungle trekking, open water swimming, river and ocean paddling, mountain biking, canyoneering, scuba diving, and spelunking. Participating were 76 four-person teams from 26 countries, including 37 teams from the United States. Subsequently, nine other EcoChallenge participants who became ill were identified in California (five in San Diego County, two in Orange County, and two in Los Angeles). To identify additional athletes with febrile illness, an EcoChallenge participant list was obtained from race organizers, and a telephone survey was administered by CDC with the assistance of several state public health departments. As of September 13, 82 (53%) of 155 U.S.-based athletes have been contacted; 37 (45%) reported having fever and 12 (15%) were hospitalized. No deaths have been reported.

On September 12, serum specimens obtained from two hospitalized athletes from Los Angeles were tested at CDC for leptospirosis using the Dip-S-Ticks* assay (Leptospira INDX Dip-S-Ticks; Integrated Diagnostics, Baltimore, Maryland) and the Pan-Bio* enzyme-linked immunosorbent assay (ELISA) IgM test (PanBio, Brisbane, Australia). One athlete tested positive with both tests on an acute-phase serum specimen obtained 4 days following onset of fever. The second athlete tested negative with both tests on the acute-phase specimen but positive with both tests on a follow-up specimen obtained 4 and 6 days following onset of fever.

On the basis of laboratory test results and the clinical features of illness, CDC advises the following to clinicians caring for EcoChallenge participants. First, asymptomatic athletes that were taking chemoprophylaxis for leptospirosis (i.e., 200 mg oral doxycycline weekly) should ensure that their final weekly dose was taken following completion of the race (1). Second, although the merits of one dose of postexposure chemoprophylaxis with 200 mg oral doxycycline are unknown, asymptomatic athletes who participated in the race and who were not taking chemoprophylaxis for leptospirosis may wish to discuss the single-dose option with their physician. Third, for athletes with mild symptoms consistent with leptospirosis, treatment should include 7 days of oral doxycycline, 100 mg twice daily (2). Finally, for hospitalized patients with severe illness (e.g., persistent high-grade fever, impaired hepatic or renal function, or severe neurologic disturbances, including coma, hemiplegia, or transverse myelitis), treatment should include 7 days of intravenous penicillin G, 1.5 million units every 6 hours (3). As with other spirochete infections, a Jarisch-Herxheimer reaction can develop following the initiation of penicillin therapy for leptospirosis (4). Although these reactions serve as an indicator of therapeutic efficacy, they can be associated with increased morbidity and mortality; patients receiving intravenous penicillin should be monitored for shocklike symptoms.

On September 13, CDC issued an advisory ( about the probable leptospirosis outbreak associated with the EcoChallenge event to raise awareness among health-care workers and participants of the event in Borneo. The Meningitis and Special Pathogens Branch (MSPB) at CDC is interested in receiving reports through state and local health departments of additional participants who have been ill or have had fever since August 21. In addition, MSPB will test clinical specimens for leptospirosis received through state and local health departments.

Reported by: California Dept of Health. Idaho Dept of Health. Council of State and Territorial Epidemiologists, Atlanta, Georgia. Meningitis and Special Pathogens Br, Div of Bacterial and Mycotic Diseases, National Center for Infectious Diseases; and EIS officers, CDC.


  1. Takafuji ET, Kirkpatrick ET, Miller JW, et al. An efficacy trial of doxycycline chemoprophylaxis against leptospirosis. N Engl J Med 1984;310:497500.
  2. McClain BL, Ballou WR, Harrison SM, Steinweg DL. Doxycycline therapy for leptospirosis. Ann Intern Med 1984;100:6968.
  3. Watt G, Padre LP, Tuazon ML, et al. Placebo-controlled trial of intravenous penicillin for severe and late leptospirosis. Lancet 1988;8563:4335.
  4. Tappero JW, Ashford DA, Perkins BA. Leptospira species (Leptospirosis) 5th ed. In: Mandell GL, Bennet JE, Dolin R, eds. Principles and practice of infectious diseases. New York, New York: Churchill Livingstone, 1999;2495--501.

* Use of trade names and commercial sources is for identification only and does not constitute endorsement by CDC or the U.S. Department of Health and Human Services. 

Disclaimer   All MMWR HTML versions of articles are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the electronic PDF version and/or the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices.

**Questions or messages regarding errors in formatting should be addressed to

Page converted: 9/14/2000


Safer, Healthier People

Morbidity and Mortality Weekly Report
Centers for Disease Control and Prevention
1600 Clifton Rd, MailStop E-90, Atlanta, GA 30333, U.S.A


Department of Health
and Human Services

This page last reviewed 5/2/01