Bilharzia

Hello Readers,

Part of the goal of this blog is to inform you about issues that the people of Malawi are facing.  We have talked about poverty, lifestyles, and new technologies, but have not spent much time talking about diseases.  We have all heard about HIV, AIDS, and malaria causing huge problems in Africa, but a lesser known disease has had a resurgence in Lake Malawi: Bilharzia.  Since I enjoy science, in particular the study of parasites, I thought it would be interesting to talk to you about this widespread disease.

Also known as Schistosomiasis, Bilharzia is caused by parasitic worms and is contracted through infected water.  Here’s how it works:  the eggs of the worms hatch in water, and invade a nearby snail.  The worms grow and mature inside of the snail, then leave the snail’s body and re-enter the water, where they wait for a mammal to enter the water.  Once an unsuspecting mammal (possibly human) enters the water, the worms enter the mammal’s body through the skin, and move to the bloodstream, where they grow and reproduce.  Sometimes, the worms enter the intestines, where they reproduce so that their eggs will leave the body with other waste, and enter another body of water to start the life cycle over again.  Here’s a chart of the lifecycle:

Bilharzia is mainly found in developing countries where people do not have access to adequate sanitation and clean water services.  Bilharzia has been found in most African countries, including Malawi, especially in areas around Lake Malawi.  The World Health Organization estimates that 207 million people worldwide are infected with the disease, and 700 million people are at risk of contracting the disease.  Here’s a map from the CDC of the distribution of Bilharzia:

The symptoms of Bilharzia are as follows:

  • Headache
  • Fatigue
  • Fever
  • Abdominal Pain
  • Enlarged Liver
  • Anemia
  • Rash
  • Intestinal Damage
  • Lung Damage
  • Death

Though Bilharzia rarely leads to death, it is often a chronic disease whose symptoms can put strain on a local population.  The symptoms are not caused by the actual worms, but by the immune system’s response to the worms and the worms’ eggs in the body.  Treatment of the disease is simple: a drug called Praziquantel that kills the adult worms.  Prevention is more difficult and complicated.  Some governments focus on killing the snails that host the immature worms, while others focus on informing their citizens about the risk factors for the disease.  Though no vaccine currently exists, many scientists are working towards this important step in prevention.  In addition, there are a few organizations that are working on controlling the disease and preventing its spread:

For more information on Bilharzia, check out these websites:

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