Leptospirosis is a zoonosis, caused by pathogenic spirochetes belonging to the genus Leptospira. Many mammalian species and amphibians may act as reservoirs. Leptospira colonize the renal tubules of chronically infected reservoir animals and are shed via urine into the environment, and then usually gain entry to the host via mucosal surfaces or damaged skin. Clinical symptoms range from a self-resolving acute febrile illness to severe, sometimes fatal disease (Weil disease).