Preventing Soil Transmitted Helminths

Kilifi Kids has worked for the past several years to reduce the burden of illness caused by soil transmitted helminths (STH) and schistosomiasis (hookworms in humans) by ensuring that the children of Kilifi, Kenya are provided with medication to combat these illnesses.  In addition to treating the problem, we hope to assist the Kilifi community in preventing infection in the first place.

Soil transmitted helminths refers to a category of intestinal worms, which as the name implies, infect people who come in contact with STH contaminated soil. Worldwide, these are the most common infections, but primarily impact poor communities that lack good hygiene and sanitation systems. Infections are most common in sub-Saharan Africa, the Americas, China, and East Asia. According to the World Health Organization, worldwide incidents of infection are:

  • A. lumbricoides over 1 billion people
  • T. trichiura 795 million people
  • Hookworms (Ancylostoma duodenale and Necator americanus) 740 million people

These worms cause a number of symptoms, including diarrhea, abdominal pain, malaise, and weakness.  These symptoms often prevent infected individuals from working and attending school. They may even stunt growth in children and cause cognitive growth retardation.  Hookworms also cause intestinal bleeding which may lead to anemia. Additionally, STHs are often co-infections with other diseases like tuberculosis, malaria, and HIV, leading to more serious consequences from these already debilitating infections.


The worms live in an infected person’s intestine, and eggs are released into the environment in the form of feces. For some types of worms, infection takes place when the eggs are consumed by a person: when he puts his fingers in his mouth or consumes fruits or vegetables that haven’t been properly washed, cooked, or peeled. Hookworm is transmitted through the skin, typically when a person is walking barefoot in contaminated soil.


No vaccine exists to prevent infection by STHs.  Kilifi Kids has coordinated and funded de-worming events, which provide medication to all kids, killing the intestinal worms in people who are infected with the worms.  However, the medication does not have a prophylactic affect, and the ultimate goal is to prevent people from getting infected in the first place. At this time, prevention must occur through behavior changes.  Several seemingly simple actions can help prevent infection, but in the current environment they may be difficult to implement due to lack of resources.  These actions will be examined in more detail in later blog posts.

  • Wear shoes, especially in areas that are likely to be contaminated with feces.
  • Use good sanitation practice when eating and preparing food: Wash hands and food in clean water, peel fruit and vegetables, or cook foods.
  • Create designated places to go to the bathroom.  Ideally these will be permanent structures, but they should not be close enough to water sources to contaminate the water.
  • Don’t use human feces as fertilizer.

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