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A study of the relations between plasma haptoglobin levels and malaria endemicity was carried out on selected specimens collected in 1980-1985 during studies on malaria transmission in various populations of the Brazzaville region of the Republic of the Congo. The prevalence of ahaptoglobinemia in school-children is 2.2% in Moungali and 2.9% in Poto-Poto, two districts of Brazzaville where malaria transmission intensity is less than one infective mosquito bite per person per year and malaria prevalence in schoolchildren is less than 10%. In contrast, ahaptoglobinemia prevalence is 48% in schoolchildren from the village of Djoumouna, where malaria transmission intensity reaches 1,000 infective bites per person per year and malaria prevalence in schoolchildren is 94%. Intermediate values, between 11.1% and 23.4% are observed in schoolchildren from Talangaï, Massina, and Linzolo, districts or villages where malaria transmission intensity is between 20 and 250 infective bites per person per year and malaria prevalence in schoolchildren is between 66% and 81%. These findings indicate that ahaptoglobinemia prevalence is correlated with the level of malaria endemicity and provide additional support for the hypothesis that malaria is the main cause of ahaptoglobinemaia in African populations. The haptoglobin system may be of considerable interest in the investigation of the mechanisms of anemia in malaria.

The lack of serum haptoglobin in Africans has been investigated in the Congo, Central Africa, where HpO prevalence is about 30%. This study shows that it is possible to suppress ahaptoglobinaemia within a few weeks by antimalarial chemoprophylaxis, that it does not occur in protected individuals, that ahaptoglobinaemia reappears at its original incidence levels after interruption of chemoprophylaxis, and that some individuals are more susceptible in relation to Hp2 gene. Malaria is the only significant cause of ahaptoglobinaemia in subjects both with and without detectable parasitaemia. The possible mechanisms involved are discussed.