Freshwater Swimming


In some countries, freshwater can be contaminated by a microscopic parasite that causes a disease known as schistosomiasis.

Places likely to harbour pests are the shallow edges of lakes and streams with abundant aquatic vegetation.
This parasite quickly penetrates healthy skin and enters the blood stream and certain organs such as the intestines, liver and bladder.
The incubation period may be long (from 14 to 84 days).
Itching and hives can appear within hours of swimming or up to one week after contact.
The treatment is praziquantel, available at your pharmacy.

Symptoms of acute infection include:

  • Fever
  • Muscle pain
  • Diarrhea
  • Respiratory symptoms


Some freshwater rivers and streams contaminated by animal urine can also contain a bacterium that causes a disease known as leptospirosis.

The disease occurs when the bacterium penetrates the skin through a scratch, through the mouth, eyes or nose.
The risk increases especially after heavy rain or a cyclone. Certain water sports such as kayaking and rafting are often associated with an increased risk of catching leptospirosis.
Direct transmission can also occur from simple contact with infected animals, or by a bite.
Leptospirosis can also be spread by ingesting water or food contaminated with the bacteria. 

Symptoms can vary widely and may include the following:

  • Fever
  • Headache
  • Muscle pain
  • Pinkeye (conjunctivitis)
  • Nausea, vomiting

Prevention :

Avoid swimming in :

  • Ponds
  • Rivers
  • Waterfalls
  • Lakes
  • Ditches
  • Bathing in fresh water if you have scratches or cuts

Other forms of prevention :

  • Wear protective clothing in fresh water and keep your mouth closed
  • Avoid contact with domestic and wild animals, especially rodents
  • Do not drink or touch the water
  • Do not rely on local residents telling you that the water is not contaminated
  • Do not rely on the fact that other people have been swimming in the water
  • If you need to cross through a river or stream, put on rubber boots
  • If you come in contact with the water, use a clean towel to wipe it off your skin immediately and vigorously (note : does not fully prevent schistosomiasis)
  • Do swim in a pool that has been properly treated with chlorine

Source :
Source : Guide d’intervention en santé voyage
Source :
The information provided is for personal use, reference and education only and is not intended to be a substitute for a Physician’s advice, diagnosis or treatment. Please consult your healthcare professional for specific information on personal health matters.