Schistosomiasis or bilharzia is a disease caused by worms, which can be contracted through contact between the skin and contaminated fresh water, for example when swimming, bathing or wading. The sea and swimming pools with chlorine do not pose any risk.
The symptoms depend on the stage of the disease:
- An itchy skin rash sometimes occurs within several hours after infection. This rash usually disappears on its own within a few days.
- Flu-like symptoms with a fever can sometimes develop after two to six weeks and can persist for days to weeks. This is called acute schistosomiasis or "Katayama syndrome".
- Chronic symptoms can develop after months or years. These symptoms primarily affect the intestines or the urinary tract.
Schistosomiasis primarily occurs in rivers and lakes in:
- South America
- Central America
- The Middle East
There is no vaccine or medication to prevent infection.
Avoid contact with potentially infected water; this means no swimming, paddling or water sports (such as rafting or kayaking) in lakes or rivers in high-risk areas.
You cannot prevent infection by applying insect-repellent products or by drying yourself thoroughly after water contact.
A preventive treatment after swimming in potentially infected water is pointless, as the treatment only works at a later stage, once the larvae have grown into adult worms.
The parasite can be killed by one of the following intervention:
- Purify water by chlorine, UV rays or filtration, if done correctly.
- Boil water, or heat it to 50 °C for at least five minutes.
- Store water for one to three days (depending on ambient temperature)