Leptospirosis

Description

Leptospirosis is a widespread zoonosis that is endemic worldwide, with a higher incidence in tropical climates, and infects a variety of wild and domestic animals that excrete the organism in their urine or in the fluids of parturition. Human infection occurs through exposure to water or soil contaminated by infected animals and has been associated with canoeing, kayaking, wading, and swimming in contaminated, untreated open water. The acute generalized illness associated with infection can mimic other tropical diseases (for example, dengue fever, malaria, and typhus), and common symptoms include fever, chills, myalgia, nausea, diarrhea, cough, and conjunctival suffusion. Manifestations of severe disease can include jaundice, renal failure, hemorrhage, pneumonitis, and hemodynamic collapse. The laboratory diagnosis of leptospirosis requires culture of the organism or demonstration of serologic conversion using the microagglutination test (MAT). However, culture is relatively insensitive and requires specialized media, and the MAT is difficult to perform and requires expertise. Therefore, availability of these techniques has been restricted to reference laboratories. Recently, several rapid and simple serologic tests have been developed that are reliable and commercially available.

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Occurrence

Leptospira proliferate in fresh water, damp soil, vegetation, and mud. The occurrence of flooding after heavy rainfall facilitates the spread of the organism because, as water saturates the environment, leptospira present in the soil pass directly into surface waters. Leptospira can enter the body through

cut or abraded skin, mucous membranes, and conjunctivae. Ingestion of contaminated water can also lead to infection.

Risk to Travelers

Travelers participating in recreational water activities, such as white water rafting, adventure racing, or kayaking, in areas where leptospirosis is endemic or epidemic could be at increased risk for the disease, particularly during periods of flooding. Travelers who might be at increased risk for leptospirosis and who develop febrile illness should be advised to consider leptospirosis as one possible cause and to seek appropriate medical care.

Preventive Measures

There is no vaccine available to prevent leptospirosis. Travelers who might be at an increased risk for the disease should be advised to consider preventive measures such as wearing protective clothing and minimizing contact with potentially contaminated water. Such travelers also might benefit from chemoprophylaxis. Until further data become available, the Centers for Disease Control and Prevention recommends that travelers who might be at increased risk for leptospirosis be advised to consider chemoprophylaxis with doxycycline (200 milligrams orally, once a week), begun 1 to 2 days before exposure and continuing through the period of exposure.

Treatment

Treatment with antimicrobial agents (for example, penicillin, amoxicillin, or doxycycline) should be initiated early in the course of the disease, and intravenous antibiotics should be used for travelers with severe manifestations.

Credits: National Center for Infectious Diseases