The global strategy for schistosomiasis control is the reduction of morbidity, which is based on the reduction of the worm load. No vaccine is yet available. Attention is focussed on detection and treatment and vector control. In a control programme, in the first place information should be obtained on the extent of the problem in a district (frequency and severity of infections, age distribution of those infected, geographical locations, knowledge of local snails, etc.). Several possibilities exist, each of which has its advantages and disadvantages. Mass treatment can be undertaken with praziquantel (treat everyone without screening). Selective treatment of infected people can also be carried out following active screening. Treatment can be restricted to a particular group (e.g. all schoolchildren or children from specific school years). Passive screening (all those people who attend a health centre) is also possible. In each case, repeated interventions will be necessary in view of the fact that a proportion of the population is always missed the first time. Re-infections also occur in previously treated people and there are often migrations of infected people from other districts after the first intervention. Supervision with the monitoring of progress and various problems (quality control), and the provision of the necessary feedback and support are essential components of a control programme. Control of morbidity should not be seen separately from control of transmission. Health education is not effective if it is not associated with an improvement in sanitary conditions in the district. The avoidance of contact with contaminated water is only possible if there is an alternative. Hence the importance of a technical infrastructure and its maintenance (washing areas, showers, toilets, footbridges over canals, etc). It is obvious that these are only meaningful if they are accepted and used. The erection of numerous bridges over canals and the use of water pumps (drinking water, washing areas) reduce contact with potentially contaminated water. Water pumps should be of a design that allows inexpensive local repairs to be made.

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It is also possible to try to control the vectors. Snails like mud and the presence of water plants. If there is a large amount of deep shadow in places where the vectors are present, the latter will have less food (snails eat algae and plants, which are dependent on photosynthesis). No shadow at all, however, will reduce egg production. Control of water plants and vegetation involves infrastructural changes. Covering over irrigation channels can limit snail populations. Cleaning of canals or the use of concrete for irrigation canals can be useful. Snail control by chemical molluscicides cannot be sustained in the long-term (too expensive and too much collateral ecological damage). The efficacy of biological control of the vector still needs to be demonstrated. The use of certain plants with a molluscicidal effect is being studied.

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It should be noted that artemether has a preventive effect on S. mansoni and S. japonicum. Taking one tablet every two to three weeks (6 mg/kg) reduces the risk considerably. Naturally, this is a dangerous strategy to apply in a P. falciparum area. In malaria-free areas (certain regions of Brazil and Venezuela, Egypt), it may be considered. It is worth considering in foci where eradication is near, e.g. Botswana. In emergencies and for some travellers, it may be beneficial. Cyclosporin also exhibits very long-term (up to 100 days) preventive properties, but its use is only experimental.