A critical analysis of the published data on the association between blood group A and hepatosplenic schistosomiasis revealed a significant heterogeneity among samples. On the basis of, first, the known distribution of the blood groups within different racial groups in Northeastern Brazil and secondly, of the greater resistance of the Brazilian Negro to the development of the severe forms of the disease, it is suggested that the association demonstrated by the published data may reflect a racial effect on the clinical evolution of schistosomiasis.
Schistosomiasis; Blood groups