Effects of a decade of chemotherapeutics on the prevalence of bilharziasis in a settled community : chemotherapy as a method of control, alone and in combination with molluscicides, used at Limpopo irrigation Scheme, Mozambique and Philadelphia Mission, Dennilto

Abstract

From the earliest publications of Harley in 1864 setting out the cause of endemic haematuria in the Cape and Natal to the present day, many prominent investigators in So uth Africa have recorded their data on several aspects of the disease and many international congresses held here have made contributions. Yet basic data on the epidemiology and pathology of bilharziasis are still incomplete. In these circumstances some quantifications on the importance of the infection are justified to provide a basis for priority consideration . Wright (1968 ) states that bilharziasis is endemic in 71 countries of the world having a total population of 1362 million. Of these ab out 124 million are sick with the disease. On the African continent he considers that 91 million are infected . Similar calculations for the subcontinent show that 11,25 million are infected. The subcontinent can be divided into the heavily infected areas with severe pathology, such as Malawi, Mozambique and Rhodesia : areas less heavily infected with lesser pathology, i . e ., South Africa, Zambia and Swaziland : and the lightly infected areas with light pathology, i.e., Angola, Botswana and South West Africa, with no infection reported from Lesotho. The spread of the disease is largely related to water impoundment and conservation. Rhodesia and the Republic of South Africa are at greatest risk because of expanded water programmes. One-third of the land area can be considered endemic for bilharziasis, inhabited by 11, 25 million infected people. The magnitude of the disease can be appreciated by "the size of the population infected with these parasites, serious illness even for a minority of these constitutes a major health problem" (Gear 1974).