Definition of Leptospirosis:

Leptospirosis is a rare and severe bacterial infection that occurs when people are exposed to certain environments.

Causes, incidence, and risk factors:

Leptospirosis is caused by exposure to several types of the Leptospira bacteria, which can be found in fresh water that has been contaminated by animal urine. It occurs in warmer climates.

It is not spread from person to person, except in vary rare cases when it is transmitted through breast milk or from a mother to her unborn child.

Risk factors include:

• Occupational exposure -- farmers, ranchers, slaughterhouse 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 livestock, rainwater catchment systems, and infected rodents

Leptospirosis is rare in the continental United States. Hawaii has the highest number of cases in the United States.