Description

Leptospirosis is a bacterial zoonosis that is endemic worldwide, with a higher incidence in tropical climates (1). A variety of wild and domestic animals may act as reservoirs for leptospires, excreting the organism in their urine or fluids of parturition. Humans may be infected through direct contact with urine or fluids of parturition of infected animals, or through contact with contaminated water or soil. A variety of occupations have traditionally been associated with increased risk of leptospirosis, including farming, veterinary, and abattoir work.

Occurrence

Leptospira proliferate in fresh water, damp soil, 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 accumulate in surface waters (2). Leptospira can enter the body through cut or abraded skin, mucous membranes, and conjunctivae. Ingestion of contaminated water may lead to infection.

Risk for Travelers

Travelers participating in recreational water activities, such as whitewater rafting, adventure racing, or kayaking may be at increased risk for the disease, particularly following periods of heavy rainfall or flooding and even in areas not previously considered endemic (3). Recent outbreaks of leptospirosis in the US have occurred in Illinois and Florida (CDC, unpublished data), while leptospirosis is endemic to Hawaii (4,5). Outbreaks in which US residents acquired leptospirosis have also occurred recently in Malaysian Borneo and Costa Rica (2,6).

Clinical Presentation

The acute, generalized illness associated with infection can mimic other tropical diseases (e.g., dengue fever, malaria, and typhus), and common symptoms include fever, chills, myalgias, nausea, diarrhea, and conjunctival suffusion (1). Manifestations of severe disease can include jaundice, renal failure, hemorrhage, pneumonitis, and hemodynamic collapse. Confirmation of leptospirosis requires culture of the organism or demonstration of serologic conversion by the microagglutination test (MAT); however, culture is relatively insensitive and requires specialized media, and the MAT is difficult to perform. The availability of these techniques has been restricted to reference laboratories. Recently, several rapid, simple serologic tests have been developed that are reliable and commercially available (7).

Prevention

No vaccine is available in the United States to prevent leptospirosis. Travelers who might be at an increased risk for infection should be advised to consider preventive measures such as wearing protective clothing, covering cuts and abrasions with occlusive dressings, and minimizing contact with potentially contaminated water. Such travelers may also benefit from chemoprophylaxis (3). Until further data become available, CDC recommends that travelers who might be at increased risk for leptospirosis be advised to consider chemoprophylaxis with doxycycline (200 mg orally, weekly), begun 1-2 days before, and continuing through, the period of exposure. Travelers who may be at increased risk for leptospirosis and who are also in need of malaria chemoprophylaxis should consider using doxycycline for both indications. (See Table 4-10 for recommended doses.)

Treatment

Missed or delayed diagnosis of leptospirosis is common, due to its non-specific clinical presentation and a low index of suspicion among healthcare providers in non-endemic areas. Treatment with antimicrobial agents (e.g., penicillin, amoxicillin, or doxycycline) should be initiated early in the course of the disease if leptospirosis is suspected (1). Aggressive supportive care may be required for respiratory, renal, and hemodynamic compromise. An infectious diseases or tropical medicine specialist should be consulted.

References

1. Levett PN. Leptospirosis. Clin Microbiol Rev. 2001;14:296-326.
2. Sejvar J, Bancroft E, Winthrop K, Bettmyer J, Bajani M, Bragg S, et al. Leptospirosis in “Eco-Challenge” athletes, Malaysian Borneo. Emerg Infect Dis. 2003;6:702-7.
3. Haake DA, Dundoo M, Cader R, Kubak BM, Hartskeerl RA, Dejvar JJ, et al. Leptospirosis, water sports, and chemoprophylaxis. Clin Infect Dis. 2002;34:e40-3.
4. Morgan J, Bornstein SL, Karpati AM, et al. Outbreak of leptospirosis among triathlon participants and community residents in Springfield, Illinois, 1998. Clin Infect Dis. 2002;34:1593-9.
5. Park SY, Effler PV, Nakata M, et al. Leptospirosis after flooding of a university campus–Hawaii, 2004. MMWR Morbid Mortal Wkly Rep. 2004;55:125-127.
6. CDC. Outbreak of leptospirosis among white-water rafters–Costa Rica, 1996. MMWR Morbid Mortal Wkly Rep. 1997;46:577-579.
7. Bajani MD, Ashford DA, Bragg SL, Woods CW, Aye T, Spiegel RA, et al. Evaluation of four commercially available rapid serologic tests for diagnosis of leptospirosis. J Clin Microbiol. 2003;41:803-9.