Leptospirosis is a zoonosis of worldwide distribution caused by infection with L. interrogans, a pathogenic spirochete. The organism infects a variety of animals, especially rodents and animals associated with farming. Humans represent only incidental infection usually through work-related contact through skin or mucous membranes, typically after exposure to water or soil contaminated with urine from an infected animal or via drinking of or bathing in contaminated water. The main occupational groups at risk are farm workers, field agricultural workers, plumbers, sewer workers, sanitation workers and military troops