Leptospires are spirochetes that may be free-living saprophytes found in freshwater or may cause acute or chronic infection of animals. The family Leptospiraceae comprises three genera: Leptospira Leptospira Leptonema Leptonema, and Turneriella Turneriella. Within the genus Leptospira, three clades can be distinguished, of pathogens, nonpathogens, and an intermediate group. Leptospires are further divided into serovars; antigenically related serovars are clustered into serogroups for convenience.