Leptospirosis is a zoonotic disease that occurs in a variety of domestic and wild animals. In mild cases, there are no obvious symptoms, and in severe cases, it can be fatal. Human infections are rarely seen in the United States. Leptospira persists in nature through chronic kidney infection of carrier animals (typically rats, dogs, cattle, horses, sheep, goats and pigs). These animals excrete leptospira in their urine for several years.