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Leptospirosis is a zoonotic bacterial disease acquired by exposure to water contaminated by the urine of infected animals. Rodents are the usual reservoir, although pigs, dogs, and cattle can harbor the organism. It is most commonly attained by indirect skin or mucosal contact through occupational work, such as sugarcane or rice farming, or through recreational activities such as rafting, swimming, and hiking. Slaughterhouse workers can acquire leptospirosis through contact with infected body fluids. Leptospirosis is most common in tropical regions, especially during the rainy season.
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The incubation period is usually 7 to 14 days; more than 90% of cases are asymptomatic or mild and self-limited. Typical symptoms include the abrupt onset of high fever, chills, headache, severe myalgias, conjunctival suffusion (dilatation of vessels without inflammation or exudate), cough, jaundice, abdominal pain, rash, or diarrhea. Aseptic meningitis is common. Dermatologic findings are nonspecific and include macular, papular, and petechial rashes. Approximately 10% of patients develop the potentially life-threatening icteric form known as Weil syndrome. The initial symptoms are indistinguishable from the milder form until several days after the onset when complications such as renal failure, liver failure, rhabdomyolysis, pulmonary hemorrhage, or cardiopulmonary failure develop.
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Laboratory findings in leptospirosis are nonspecific. An elevated creatine kinase is common. Markedly elevated bilirubin values are seen in Weil syndrome. Culture of the organism is possible, but diagnosis is usually serologic. Rapid test kits are available in some countries.
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Management and Disposition
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Empiric treatment is often indicated. Outpatient management with doxycycline, penicillin, amoxicillin, or a macrolide can be considered for mild illness. Severe disease is treated with IV penicillin or ceftriaxone. Supportive care, including optimal fluid management, is essential to help prevent or ameliorate renal dysfunction. Severely ill patients often need ventilatory support in an intensive care unit and dialysis.
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About half of the cases reported in the United States are from Hawaii, with increased outbreaks during periods of heavy rainfall and flooding.
Consider leptospirosis in an acutely febrile adventure traveler with recent freshwater exposure.
The presence of conjunctival suffusions, with or without jaundice, is highly suggestive of leptospirosis.
A Jarisch-Herxheimer reaction may occur after treatment with antibiotics.
Weekly doxycycline is effective prophylaxis for short-term travelers to highly endemic areas.
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