Adventure Sports Travel Health Tropical Medicine Wilderness


Mud puddleLeptospirosis is the most common zoonotic infection, worldwide.  Outdoor athletes (hikers, cyclists, etc) are especially vulnerable to this infection because transmission is often through contact with infected fresh water.  Simple cuts, scrapes or breaks in the skin can help the infected water enter the bloodstream, making infection more likely.  I frequently get cuts or scrapes, especially on my legs, while riding or running.  To make it worse, one of my favorite things to do is run or ride through a big puddle!


A spirochaete infection that is found worldwide and associated with skin contact and water contaminated with infected urine. Approximately 200 different serotypes are know and severity of disease seems to vary depending on the causative type/serovar. Symptoms include a sudden onset of fever, headache, and leg myalgias. Symptoms may persist for up to a month. This disease typically infects local rice or sugarcane workers and hikers/backpackers/campers.  The more severe form of leptospirosis may be known as Weil’s Syndrome.


Worldwide distribution, except polar regions.  Very common in tropical and subtropical climates

 Transmission/ Incubation:

Transmitted via skin contact with infected animal urine or water containing infected urine. Broken skin such as skinned knees or scrapes increase transmission. Incubation is generally around 10 days but may take up to a month.


Avoid swimming or wading in contaminated water, use of protective boots and/or clothing and there is some theory that a prophylactic does of doxycycline 200 mg once per week may prevent disease in high risk populations.


Leptospire agglutination titers (4 fold rise) or isolation of leptospires from blood


Prompt recognition and early treatment is key. Penicillin is the first line antibiotic. Doxycycline (100 mg orally twice per day) or Erythromycin, for those allergic to penicillin, are also good options. If using penicillin, watch for a potential Jarisch-Herxheimer reaction.

Leptospirosis Red Flags:

  • History of contact with fresh waster or mud
  • Cuts, scrapes or other breaks in the skin
  • Animal contact
  • Muscle aches, especially in legs and/or lower back
  • Fever
  • Jaundice

Weil’s Disease

The more severe form of leptospirosis infection, occuring  in about 10% of cases.  Weil’s disease classically features jaundice and kidney damage.  

Leptospirosis is something that should be in the back of the mind of all travelers who are coming into contact with fresh water, especially in tropical climates.  Outbreaks of leptospirosis are frequently seen following flooding, as in Hawaii.  Adventure sports participants need to remember they are an especially high risk group and a chilling report of infections can be found in the Emerging Infectious Diseasesjournal.  Participants in a Malaysian adventure race, one I thankfully missed, showed that 42% of contacted participants met the clinical case definition of the disease.  White-water rafters and kayakers should also be aware of this article, published in MMWR.

For some more info:

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