When parasitic disease, whether of protozoan or other origin, gets out of control, it is mostly due to increasing, rarely decreasing, human population pressure and/or to changes of human behaviour. By his various activities man changes his environment; it thus appears logical to try to control disease by environmental management. The goal thereof is not to eradicate disease but rather to establish a new, tolerable equilibrium.

Environmental management has been shown to alleviate the situation. It ought not, however, be seen as a unique measure; it must rather be an integral part of a comprehensiveplan which includes various other approaches simultaneously, such as medical treatment, vector and intermediate host control, improvement of water supply and nutrition, improvement of housing and sanitary conditions.

Environmental management is thus closely interlinked with traditional occupations, customs and beliefs. In addition, environmental management, in the long run, can be undertaken only by local populations. These, therefore, need information and motivation, information through acceptable health education, motivation through long-lasting government support, from all levels and with all departments concerned co-operating, and possibly through appropriate, unobtrusive expatriate assistance.