Soil-transmitted helminthiases are widely distributed in tropical and subtropical areas. Worldwide, it has been estimated that more than one billion people are infected with soil-transmitted helminthiases infections, of whom more than 300 million suffer from severe morbidity.

There are four species of helminth causing soil-transmitted helminthiases: hookworms Ancylostoma duodenale and Necator Americans, roundworm Ascariasis lumbricoides, and whipworm Trichuris trichura. Each species is responsible for a separate set of signs and symptoms, in fact for a separate disease. Symptoms include nausea, tiredness, abdominal pain and loss of appetite. These infections aggravate malnutrition and amplify rates of anaemia.

In the Eastern Mediterranean Region, the population requiring preventive chemotherapy for soil-transmitted helminthiases constituted 14% of those requiring the chemotherapy worldwide in 2008. In 2003, estimates of cases of soil-transmitted helminthiases infections were 23 million for ascariasis, seven million for trichuriasis and 10 million for hookworm disease.