Distribution of Duffy Phenotypes among Infections in Sudan.

Negative Duffy expression on the surface of human red blood cells was believed to be a barrier for infection in most Africans. However, has been demonstrated to infect Duffy-negative individuals in several Central and East African countries. In this study, we investigated the distribution of Duffy blood group phenotypes with regard to infection and parasitemia in Sudan. Out of 992 microscopic-positive malaria samples, 190 were identified as positive infections. Among them, 186 were mono-infections and 4 were mixed and infections. A subset of 77 samples was estimated with parasitemia by quantitative real-time PCR. Duffy codons were sequenced from the 190 positive samples. We found that the Duffy Fy(a-b+) phenotype was the most prevalent, accounting for 67.9% of all infections, while homozygous Duffy-negative Fy(a-b-) accounted for 17.9% of the infections. The prevalence of infection in Fy(a-b+) and Fy(a+b-)were significantly higher than Fy(a-b-) phenotypes ( = 0.01 and < 0.01, respectively). A significantly low proportion of infection was observed in Duffy negative individuals Fy(a-b-). This study highlights the prevalence of in Duffy-negatives in Sudan and indicates low parasitemia among the Duffy-negative individuals.