Soil-transmitted helminths

• Helminth is a technical name for worm.
• There are 3 species of STH which are particularly critical in terms of public health: Roundworm, Whipworm and Hookworm. 

• A person who is infected with STH has parasite eggs in their faeces.
• In areas where there is no proper latrine system, the soil around the village or living area becomes contaminated with faeces containing these worm eggs.
• In the soil the eggs mature: this takes from between 2 and 4 weeks. They can then infect humans in two ways:
• eggs stick to vegetables grown in the area. If the vegetables are not carefully cooked, washed or peeled, the eggs are ingested and infect the person;
• young children often play in the soil and put their hands in their mouths without washing them. In this way they ingest the eggs and become infected.

• drinking unclean water which has STH eggs in it;
• >walking barefoot on contaminated soil. The eggs hatch into larvae which can penetrate the skin of people walking barefoot (this is only true for hookworms).

• Drink clean water and wash, cook or peel food carefully before eating it.
• Wash your hands before eating.
• Wear shoes.

There is no direct person-to-person transmission, or infection from fresh faeces, because eggs passed in faeces need about 3 weeks to mature in the soil before they become infective.

• Most of the symptoms of STH infections are very nonspecific and only become evident when the infection is particularly severe. The nonspecific symptoms include nausea, tiredness, abdominal pain and loss of appetite.
• Sometimes you will see worms in your faeces.

• Anaemia: Hookworms live in the intestine. They attach themselves to the intestine wall and feed on blood from the cut vessels and mucosal tissues. This blood loss causes anaemia.
• Vitamin A deficiency: Worms need vitamin A to live. In many countries, people do not eat enough vitamin A-rich foods. In these situations, the limited amount of vitamin A that is eaten is taken by the worms.
• Learning: Worm infected children are less able to concentrate or memorize information. They score less well in school tests.
• Intestinal obstruction: If a person is constantly infected over a long period of time, the number of worms in that person's intestine steadily increases. Eventually the number of worms can become so great that they block the intestine and the only option at that stage is surgery. This is usually the case for small children whose intestines are still relatively narrow.

• Treatment is very simple and safe.
• Take one dose of any of the following four drugs.
• If you live in an area where worms are a problem, it is a good idea to treat yourself regularly (e.g twice a year).

• Yes, the drugs are safe and WHO recommends that if you have worms, you should be treated, even if you are pregnant.
• As a general precaution, WHO recommendations state that all drugs should be taken after the first trimester

• First, you can easily avoid getting schistosomiasis by not swimming in fresh water in areas where schistosomiasis is likely to occur.
• Second, worms (both schistosomes and soil-transmitted helminths (STHs) do not cause a life-threatening disease for someone who is generally healthy and then becomes infected. The disease is only serious for people living in endemic areas who become constantly reinfected and have no access treatment.
• Third, if you get infected, the treatment is easy and safe.