Prevalence of Toxoplasma antibodies in Southern Africa

An indirect fluorescent antibody survey of the prevalence of Toxoplasma antibodies was carried out on sera from 4 regions of Southern Africa (Natal, Eastern Cape, Western Cape, and South West Africa and Botswana). The overall prevalence of seropositivity at a titre of 1/16 or higher was 20% (of 3379 sera tested), the highest prevalence occurring in Blacks (34%) and Indians (33%) of Natal, and the lowest in San (Bushmen) (9%) and Whites (12%) of South West Africa and Botswana. Differences in prevalence in these areas, and between different ethnic groups, are discussed and compared with previous studies in Southern Africa. Climatic factors affecting prevalence and transmission are compared in relation to cyst and oöcyst survival. The marked differences in prevalence between the San (9%) and the Negroid Dama (27%), both inhabiting the arid Kalahari Desert, are discussed with reference to the lifestyles of these groups.