The Duffy blood types survey in 544 subjects coming from French speaking African countries, shows the high percentage of subjects having a Duffy a- b- blood type (94%). It ought to be emphasized that this predominantly Duffy a- b- population resides in areas in where there is according to the WHO data, a very low incidence of Plasmodium vivax invasion. Moreover, we have taken for another example North Vietnam, an area where there is a large Plasmodium vivax invasion and where we have found a small percentage of Duffy negative subjects (5.6%). In agreement with many authors reporting an association between Duffy negatively and vivax malarial refractoriness, this survey demonstrate that in French speaking African areas where there is a very low incidence of Plasmodium vivax invasion we have found, as expected, a high rate of Duffy negative subject.

Anaemia during malaria is not completely understood. Fourteen cases of antierythrocyte autoimmunisation with anti-I specificity were investigated in a Paris hospital during a period of 2 years. The patients lived in Gabon and had not been taking antimalarial chemoprophylaxis. All had chronic malaria (strongly positive antimalarial immunofluorescent antibody tests). All the recognised caused for anti-erythrocyte autoimmunity were excluded. One possible explanation for these observations is some sort of interaction between I antigen and Plasmodium, the result of which facilitated penetration of the erythrocyte by the malarial parasite.