These rogues of parasites, of which there are a number of different dysfunctional families, are called by the tongue twister name of Schistosoma. There are S mansoni, S haematobium and S japonicum families and a couple of others you don’t want to meet!

The families have a complicated lifestyle and need certain freshwater snails to reproduce. These snails we call the intermediate host. When they have outstayed their welcome, the host releases huge numbers of tiny, free-swimming larvae (called cercariae) that wait around for a human so they can pierce the skin and enter the body in this way and cause the disease Bilharzia.

Even walking or wading through infected waters can put you at risk. However, you will be quite safe in seawater, as they do not like their drinks too salty. They also don’t like chlorine, so adequately chlorinated swimming pools are safe.

How will you know if you suffer from Biharzia? Although not much of a killer disease, it can nevertheless cause a lot of unpleasantness. On a yearly basis 200 million people are affected by it!  Symptoms of the initial infection can be mild, however about two weeks to three months later you could present with the following symptoms: fever, loss of appetite, diarrhea, nausea, abdominal pain, blood in urine, weight loss, weakness, headaches, cough as well as joint and muscle pains. Quite a list!  Symptoms mainly depend on which family of Schistosomiasis has decided to take up residence in your body and their target organ!

If not treated, the infection can cause damage to the liver, bladder, kidneys, lungs and the intestinal tract. To diagnose the disease the doctor will send blood, stool and urine samples to the lab, and when confirmed, you will be treated with a safe and effective pill.

As a traveler, where are you most likely to pick up the parasite? It occurs widely in most tropical and subtropical countries. But guess what? Sub Saharan Africa is the worst hit! So when you travel to lake Malawi, don’t think you will escape the onslaught! Your motto should be:


Avoid swimming, wading, washing in infected water and don’t drink it either! There is no vaccine available but fortunately it can be effectively treated.

If you are slumming it and have no alternatives and lots of time on your hands you can go on a Bilharzia killing spree by heating your bathwater to 50 ° C  for five minutes or filter the water with an effective filter.