The recent growth in popularity of adventure racing and exotic tourism has increased the number of people exposed to unusual infections, according to a Centers for Disease Control and Prevention (CDC) update published in the July 2001 Annals of Emergency Medicine

. The update reports on a bacteria-related outbreak among many of the athletes who participated in Eco-Challenge-Sabah 2000 in Borneo, Malaysia. Many race participants were infected by the Leptospira organism while swimming, kayaking or accidentally swallowing water from the Segama River.

"Emerging infections are significant public health problems, and identifying these unusual diseases is a serious challenge confronting health care providers today," said Susan C. Stone, MD, MPH, of USC Medical Center in Los Angeles, author of a related commentary in the same issue. "For example, many of the Eco-Challenge athletes' symptoms did not emerge until they returned to the United States, where physicians might be less likely to recognize and diagnose an exotic or tropical disease."

Not only does the CDC note in its report outbreaks of leptospirosis in the Eco-Challenge-Sabah, but also among travelers who were white-water rafting in flooded rivers in Costa Rica and among athletes participating in triathlons in Illinois and Wisconsin.

Leptospirosis is a disease spread from animals to humans and is found worldwide. In the United States, 100 to 200 cases occur annually, with half occurring in Hawaii. Often, the bacteria live in the animal host, are excreted through its urine, and can survive in the environment for weeks or months, particularly in tropical climates. Humans are often exposed when, after a heavy rainfall or flooding, sewage overflows into a water supply. High fever, chills, muscle aches, diarrhea, and conjunctivitis are typical symptoms of an infection caused by this organism.

Most cases of leptospirosis are mild and require only treatment with antibiotics for about seven days. The CDC is currently investigating a vaccine for people who are participating in high-risk exposure activities in areas where leptospirosis is common.

Annals of Emergency Medicine is the official peer-reviewed journal of the American College of Emergency Physicians, a national medical organization with more than 21,000 members.