Auburn University Leptospirosis in Cattle Leptospirosis is a . . .
Leptospirosis occurs worldwide and threatens cattle in Alabama and the southeastern United States.
For example, the serovar hardjo is adapted to cattle while the serovar pomona is adapted to swine. The serovar adapted to a species tends to cause less severe disease in that species than in a species not adapted to it. For this reason, the serovar pomona tends to cause a more severe disease in cattle than in swine. The signs of lepto depend on the herd's degree of resistance or immunity. In herds with adequate resistance, developed through a good vaccination program, some cattle may be infected with the organism but not show signs of disease.