Bilharziasis control in relation to water resources development in Africa and the Middle East.

As part of its world-wide programme for the control of bilharziasis, the World Health Organization has set up a Bilharziasis Advisory Team, composed of an epidemiologist and an engineer, to investigate in different countries the prevalence of the disease and its relationship to irrigation, agriculture and a variety of factors associated with the development of water resources. This paper is an appraisal of the situation in 15 countries in Africa and the Middle East, based largely on surveys conducted by the Bilharziasis Advisory Team in the period 1958-60.Analyses of data from these 15 countries indicate that about 26 million people, out of a total population of 107 million, have bilharziasis. In spite of considerable expenditure on control measures, the prevalence of the disease is increasing. This trend is closely related to water resources development. On the basis of observations in the field, it is believed that improved water management and agricultural methods, stream and water impoundment control, the proper use of molluscicides and mechanical barriers, and certain aspects of environmental sanitation offer practical solutions to this problem. The complexity of these measures requires the closest co-operation between the various agencies, national and international, concerned with agriculture, water resources and public health.