Definition of Leptospirosis:

Leptospirosis is a rare, severe, and contagious infection caused by several types of the Leptospira bacteria.

Causes, incidence, and risk factors:

Leptospirosis is caused by exposure to the bacteria, which can be found in fresh water contaminated by animal urine. It occurs in warmer climates.

Risk factors include:

• Occupational exposure -- farmers, ranchers, abattoir workers, trappers, veterinarians, loggers, sewer workers, rice field workers, and military personnel.
• Recreational activities -- fresh water swimming, canoeing, kayaking, and trail biking in warm areas.
• Household exposure -- pet dogs, domesticated live stock, rainwater catchment systems, and infestation by infected rodents.

The incidence of leptospirosis is low in the continental U.S. Hawaii has the highest number of cases in the U.S.