Abstract
Leptospirosis, caused by a spirochete of genus Leptospira, is considered the most widespread zoonosis in the world. It has a global distribution with a higher incidence in the tropics and subtropics, ranging from 10 to 100 human cases per 100,000 individuals. Leptospirosis is considered an "emerging" zoonosis due to increased contact between animals and humans and the resulting human encroachment into wildlife habitat. Climate change and its associated environmental shifts can affect the degree of transmission of leptospirosis. Surveillance for leptospirosis is important for early detection of cases because early treatment is crucial to decrease morbidity and mortality. In June 2012, the Council of State and Territorial Epidemiologists approved reinstatement of leptospirosis as a Nationally Notifiable Condition. Reinstatement of national surveillance will facilitate the assessment of the incidence, geographic distribution, trends, and risk factors associated with human cases and the identification of outbreaks and potential new animal reservoirs.