Malaria and hereditary ovalocytosis

Abstract
Hereditary ovalocytosis in Papua New Guinea is restricted to areas of endemic malaria and may confer increased resistance to the disease. The incidence of malaria was investigated in 1616 Melanesians of known red cell morphology and severity of infection determined in a smaller subsample. Ovalocytics tended to be more resistant to severe malarial infections than normocytics. The ratio of parasitaemia in 112 ovalocytics compared with 741 normocytic children was 1.05 for P. falciparum; 0.90 for P.vivax; 0.54 for P. malariae, and 0.91 for infection with any species. The difficulties in conclusively demonstrating any selective advantage of the condition are discussed.