PURPOSE

malaria remains a major public health challenge in sub-Saharan Africa. drug resistance mediated by polymorphisms in the gene contributes to the persistence of the disease on the African continent. This study investigated infection features and differences in the genotypes between symptomatic and asymptomatic malaria cases in a rural area in east-central Gabon.

PATIENTS AND METHODS

A total of 875 children aged from 5 to 185 months were screened for infection using Optima-IT rapid diagnostic tests and standard microscopy. polymorphisms at codons 86, 184 and 1246 were investigated using PCR-RFLP.

RESULTS

Among the 448 -infected children, 57.08% (n=250) were symptomatic and 42.92% (n=198) were asymptomatic ( < 0.0001). In a sub-set of 79 isolates, the wild-type N86 was more prevalent in symptomatic (100%) than in asymptomatic infections (70.7%) (=0.007). The mutant 86Y and mixed 86N/Y genotypes were observed only in asymptomatic infections. The Y184 and 184F genotype prevalences (39.1% vs 19.4% and 60.9% vs 80.6%, respectively) were not significantly different between the two groups (=0.097). The prevalence of the wild-type D1246 differed significantly between symptomatic (10.3%) and asymptomatic (100%) ( < 0.0001). The NFD and YFD haplotypes were more prevalent in asymptomatic than in symptomatic infections [(61.9% vs 31%; =0.005) and (16.7% vs 0.0%; =0.01)], whereas the NYD and YYD haplotypes were not significantly different between the two groups [(21.4% vs 14.3%, =0.39) and (0.0% vs 7.1%, =0.24)].

CONCLUSION

Our results confirm a high transmission of infection in rural Gabon, with a high prevalence of asymptomatic carriage. The higher prevalences of wild-type N86 in symptomatic infections and of D1246 in asymptomatic infections suggest a pathogenicity associated with polymorphisms in . These results highlight the need to monitor the efficacy of artemisinin-based combination therapies in Gabon.