Hereditary ovalocytosis and reduced susceptibility to malaria in Papua New Guinea.
Ovalocytosis, an hereditary condition in which most erythrocytes are oval in shape, is a polymorphism that occurs in up to 20% or more of the population in Papua New Guinea and Malaysia. Due to the geographical correlation of the trait with endemic malaria, the possibility of a selective advantage in resistance to malaria has been raised. In a study of 202 individuals with greater than or equal to 50% oval red cells matched by age, sex and village of residence with controls having less than or equal to 30% oval cells, ovalocytic subjects had blood films negative for Plasmodium vivax (P = 0.009), for P. falciparum (P = 0.044), and for all species of malaria parasites (P = 0.013), more often than controls. Among individuals parasitaemic at any time there were no clear differences in density of parasitaemia. However, in children 2 to 4 years old, parasite densities of both species were lower in ovalocytic subjects than in controls (0.01 less than P less than 0.025). The differential susceptibility to malaria infection suggested by this study has implications for the evaluation of interventions, including possible future vaccine field trials, in populations where high-frequency ovalocytosis is present.
Cattani
J A
JA
Papua New Guinea Institute of Medical Research, Goroka.
Gibson
F D
FD
Alpers
M P
MP
Crane
G G
GG
D000818:Animals; D004198:Disease Susceptibility; D004612:Elliptocytosis, Hereditary / Q000453:epidemiology / Q000276:immunology*; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D008288:Malaria / Q000453:epidemiology / Q000276:immunology*; D008297:Male; D010219:Papua New Guinea; D010963:Plasmodium falciparum / Q000276:immunology; D010966:Plasmodium vivax / Q000276:immunology