Sickle Trait Hemoglobin Does Not Influence Anopheles Biting Rates.

Children with sickle cell trait (HbAS) are protected against severe and symptomatic Plasmodium falciparum (P. falciparum) malaria. Although several within-host resistance mechanisms have been investigated, it is unknown whether this protection is attributable in part to reduced exposure to P. falciparum parasites via mosquito bites. In a 15-month cohort in Western Kenya, mosquito blood meals were matched to human hosts on the basis of short tandem repeat genotypes to determine individual mosquito biting rates. Using a multilevel multivariable model, mosquito biting behavior was assessed with respect to human β-globin genotypes, and no significant difference in biting rate was observed between individuals with wild-type (HbAA) and HbAS genotypes (biting rate ratio: 1.23; 95% CI: 0.86-1.77). These findings suggest that protection against malaria conferred by the sickle cell trait is unlikely to be attributable to reduced exposure to infectious mosquito bites.