The Threadworm (Strongyloides stercoralis)

Strongyloides stercoralis, or threadworm, is a type of roundworm that can infect humans. This parasite is is free-living in the soil and can infect a person by coming into contact with their skin.

These little roundworms are about 2mm long and actually burrow through the person’s skin to enter the system.

The Incredible Journey

Once the worms are in the system they migrate through the tissues to get to the small intestine. Sometimes they burrow under the skin leaving a red trail as they move at a rate of 5cm per day. Sometimes they even get caught in the bloodstream and are delivered to the lungs. Once there, they irritate until they are coughed up and swallowed so that they may continue their journey through the digestive system to the small intestine.

So What Are The Health Consequences Of Infection?

Symptoms of threadworm can range from very minor symptoms to death depending on the immune system of the person. Unlike other worms, threadworms multiply while inside the body. Females can actually lay up to 50 eggs per day each! Because of this, the immune system has to fight to make sure that the worm population doesn’t get out of control.

Threadworm infections in a person who has a healthy immune system can cause anaemia (low red blood cell count) from the worms feeding on blood in the gut. They can also cause other problems such as abdominal pain, cramping, bloating, malabsorbtion symptoms and chronic diarrhoea. Some people have weak immune systems such as those infected with HIV / AIDS (so common in Africa) or those taking certain types of medication to suppress the immune system. In these people the immune system can’t keep the number of worms under control and they can develop a hyperinfection. In these cases the worms reproduce out of control and the patient dies in 70-90% of cases.