schistosomiasis - MASTA Travel Health | For All Your Vaccination advice


Schistosomiasis is an infection caused by a parasite. The parasite lives on certain snails which live in fresh water, most commonly in tropical areas, especially in Africa. Water sports, swimming or showering in these waters should be avoided.
  • Symptoms An itchy rash can appear on the skin, known as “swimmers itch”. Sometimes a fever can develop 2-6 weeks later, with diarrhoea, cough or other symptoms (“Katayama fever”). Long-term infection may have no symptoms for years.
  • How do you catch schistosomiasis? The tiny parasitic worms in the water burrow through the skin. They then travel to the veins of the bladder or bowels and release eggs.
  • Incubation period Usually 2-12 weeks for the initial infection.
  • Diagnosis Blood tests no earlier than 8 weeks after contact with the fresh water can confirm the diagnosis. St


Avoid water sports, swimming or wading in fresh water lakes and rivers in the tropics. If crossing a river cannot be avoided, wear waterproof footwear and try to find an area where the water is fast flowing.


A drug called praziquantel is used to treat schistosomiasis, but is not effective in the early stage of infection - so taking it after a swim is not likely to help. Any traveller who has been in fresh water in tropical areas should see their doctor 8-12 weeks later for tests.

  • There is no vaccine available to prevent schistosomiasis.
  • Schistosomiasis cannot be caught by swimming in seawater or in chlorinated swimming pools.
  • Neither using an insect repellent, nor drying off quickly after being in the water, will prevent infection with schistosomiasis.
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