Weil disease

Weil disease is caused by spirochetes of the genus Leptospira, transmitted via contact with water, soil, or food contaminated with urine from infected animals (rodents, cattle, dogs). Organisms enter through skin abrasions or mucous membranes. The disease is classically biphasic: (1) a septicemic/leptospiremic phase with fever, myalgias (especially calves), headache, conjunctival suffusion, and flu-like symptoms lasting about a week; (2) an immune phase in which antibodies form and organisms are cleared from blood but persist in tissues (kidneys, liver, CSF), leading to aseptic meningitis in mild cases. Weil disease represents the severe, icteric form occurring in about 5-10% of leptospirosis cases, marked by the triad of jaundice (due to hepatocellular dysfunction without significant necrosis), acute kidney injury (interstitial nephritis, tubular necrosis), and hemorrhagic diathesis (due to vasculitis and thrombocytopenia, causing pulmonary hemorrhage, epistaxis, GI bleeding). Other findings include myocarditis, uveitis, and rhabdomyolysis. Lab diagnosis involves dark-field microscopy, culture (slow-growing, requires special media like Fletcher's), serology (microscopic agglutination test, ELISA for IgM), or PCR. Treatment includes penicillin G or ceftriaxone for severe disease, doxycycline for mild disease; a Jarisch-Herxheimer reaction may occur with antibiotic initiation. Prevention involves avoiding contaminated water, protective clothing for at-risk occupations (farmers, sewer workers, veterinarians), and doxycycline prophylaxis for high-risk exposure. Mortality in Weil disease can reach 5-15% due to renal failure or hemorrhage.