Leptospirosis

Leptospirosis is a zoonotic infection caused by pathogenic spirochetes of the genus Leptospira. It affects humans and a broad range of animals. Most human infections occur after exposure to urine-contaminated water or soil, often through skin abrasions or mucous membranes. Occupations at higher risk include farmers, sewer workers, veterinarians, and slaughterhouse workers, as well as recreational water users in tropical or subtropical regions with heavy rainfall.

The clinical presentation ranges from a mild, flu-like illness to a severe form known as Weil disease, which can involve jaundice, renal failure, hemorrhage, and pulmonary complications. The incubation period is typically 5 to 14 days. Early symptoms may include fever, headache, myalgias (especially calves), conjunctival suffusion, and abdominal pain; later stages may feature meningitis, liver and kidney dysfunction, or respiratory involvement.

Diagnosis is based on serology and molecular methods. The microscopic agglutination test (MAT) and IgM enzyme-linked immunosorbent assay (ELISA) are commonly used serologic tests, with PCR useful in early infection. Cultures are slow and rarely needed for routine management.

Treatment depends on illness severity. Mild cases can be treated with doxycycline or amoxicillin, while severe disease requires hospitalization and parenteral antibiotics such as penicillin G or ceftriaxone, along with supportive care. Early treatment reduces the risk of complications.

Prevention focuses on reducing exposure, including protective clothing, good wound care, rodent control, and avoiding swimming or wading in potentially contaminated water. Vaccines exist for animals and, in some regions, human vaccines are available, though not universally used. Leptospirosis occurs worldwide, with higher incidence in tropical regions and after floods; outcomes improve with timely diagnosis and treatment.