The disease is under-diagnosed in the United States. The 50 to 150 cases reported each year are probably only a fraction of the total number of infections. Increased awareness of the disease has led to increased recognition. In 1995, after widespread flooding in Nicaragua, a leptospirosis epidemic killed at least 13 persons and made more than 2,000 others sick. In 1997, nine whitewater rafters from the United States were infected during a river trip in Costa Rica.
Leptospirosis is also a problem in deteriorating inner cities that are infested with rats.
Minimize contact with fresh water, mud, and vegetation that might be contaminated with the urine of infected animals, especially rodents. Wear protective clothing, such as waterproof boots or waders, when participating in recreational or work activities that might result in contact with contaminated water. If you have any questions about the disease described above, consult a health-care provider.