The association of <i>eba-175</i> alleles with the outcome of malaria in Nigerian children

Abstract

Malaria remains a major cause of morbidity and mortality in Nigeria. Plasmodium falciparum erythrocyte binding antigen-175, eba-175, plays an important role in the invasion of host cells during falciparum malaria infection. It mediates erythrocyte invasion by sialic acid dependent binding to glycophorin A on erythrocytes. Dimorphic allelic segments, FCR-3 (F-segment) and CAMP (C-segment) have been found in the eba-175 encoding gene and associations have been reported between the dimorphism and the clinical outcome of malaria in endemic populations. The possible associations of the dimorphism with the clinical outcome of malaria were investigated in Ibadan south-west Nigeria. Blood samples were obtained from 390 children categorized into clinical categories of asymptomatic controls and uncomplicated and severe malaria cases as defined by WHO. The allelic dimorphism of eba-175 was analysed by nested polymerase chain reaction. Overall, the F-fragment was observed in a higher frequency than the C-fragment. Single infections were more frequent than mixed infections (F-/C-Fragments). The C-fragment and mixed infections were most common in the asymptomatic controls compared to the uncomplicated and severe malaria cases. The presence of C-fragments and mixed infections were significantly associated with the asymptomatic controls. The results from this study confirm the dimorphism of eba-175 in the Ibadan south-west population. We conclude that the C-fragment and mixed infections are associated with asymptomatic malaria in children in Ibadan, south-west Nigeria.

Keywords: severe malaria, mixed infections, C-fragment, eba-175, Nigeria.