How can worms be controlled?
Helminth infections can be effectively controlled by periodic chemotherapy (deworming) with safe, cheap and single-dose drugs. Treatment should ideally be implemented alongside improvements in sanitation and health education. Deworming can improve children's growth and benefit their learning, for example by increasing primary school attendance. Even though re-infection may occur after treatment, the risk of developing chronic or severe disease is greatly diminished and even reversed when treatment is initiated in childhood.
For STH and schistosomiasis, the World Health Organization (WHO) identifies three key groups for mass treatment: school-aged children, pre-school children and pregnant women. In communities where infection is common, all individuals at risk of infection should be offered treatment.
In the case of LF, the main strategy for reducing transmission is annual mass drug administration of entire populations at risk of infection for at least five years. Vector control is also sometimes effective against LF.
Drugs for soil-transmitted helminths
The main drugs recommended by WHO for treatment of STH are albendazole and mebendazole. They are administered as a single tablet to all children, regardless of size or age. One pill can cost as little as US$0.02.
GlaxoSmithKline has committed to donating 1 billion doses of albendazole every year until 2020 whilst Johnson & Johnson is donating 200 million doses of mebendazole per year. Our partner, Children Without Worms, oversees the annual donation of these drugs.
Drugs for schistosomiasis
The drug of choice to treat schistosomiasis is praziquantel which is slightly more expensive but still relatively cheap – on average US$0.20 per treatment for a school-aged child. Praziquantel is given as a single dose, but the number of pills has to be adjusted to the size of the child. The preferred method for adjustment in schoolchildren is an inexpensive 'dose-pole'. This uses the height of the child to estimate the dosage.
Drugs for lymphatic filariasis
Three drug regimens are recommended for mass drug administration targeting: ivermectin with albendazole in African countries where the disease onchocerciasis, or river blindness, occurs; diethylcarcamazine with albendazole in countries where onchocerciasis is not endemic; and twice yearly treatment of albendazole in countries endemic for loa loa, another filarial nematode species also known as African eye worm.
Two pharmaceutical companies, GlaxoSmithKline and Merck, made a pledge to donate albendazole and ivermectin, respectively, to help eliminate LF. GSK's commitment is a donation of 1 billion albendazole tablets every year until 2020, while Merck has pledged to donate as much ivermectin as necessary to eliminate LF as a public health problem.