Leptospirosis is a zoonosis with protean clinical manifestations caused by pathogenic spirochetes of the genus Leptospira. Synonyms for the disease include Weil's disease, Weil-Vasilyev disease, Swineherd's disease, rice-field fever, waterborne fever, nanukayami fever, cane-cutter fever, swamp fever, mud fever, Stuttgart disease, and Canicola fever.
The epidemiology, microbiology, clinical manifestations, and diagnosis of leptospirosis will be presented here. The treatment and prevention of this disease are discussed separately. (See "Treatment and prevention of leptospirosis".)
Leptospirosis is a widespread and prevalent zoonotic disease. It occurs in both temperate and tropical regions; the incidence in the tropics is approximately 10 times higher than in temperate regions . Leptospirosis is an under-reported disease, and there are no reliable global incidence figures. A modeling exercise by the World Health Organization's (WHO's) Leptospirosis Burden Epidemiology Group estimated that there were 873,000 cases worldwide annually with 48,600 deaths .
Various mammals are natural hosts; humans are infected incidentally after animal or environmental exposure.
Animal infection — The organism infects a variety of both wild and domestic mammals, especially rodents, cattle, swine, dogs, horses, sheep, and goats. The disease rarely occurs in cats. Animals can be asymptomatic or develop clinical infection, which can be fatal. Mortality in dogs is estimated at approximately 10 percent. Spontaneous abortion is a common outcome of leptospirosis in cattle, swine, sheep, and goats.