Genetic Polymorphisms of Pfcrt K76T and Pfmdr1 N86Y among Asymptomatic School Children in Forest Communities of Ekondo Titi Subdivision along the Cameroon-Nigeria Border Area

Aims: The study sought to quantify Plasmodium infection and molecular markers for chloroquine resistance among asymptomatic school children.

Study Design: The study was cross-sectional.

Place and Duration of Study: The study was carried out in Ekondo Titi Subdivision near Cameroon's south-western border with Nigeria from March to May and from September to October 2014.

Methodology: The prevalence of human Plasmodium species was determined by nested PCR (Polymerase Chain Reaction) using DNA from dried blood spot in six primary schools. A PCR/RFLP analysis (Restriction Fragment Length Polymorphism) was used to determine the prevalence of chloroquine resistance (CQR) associated pfcrt 76T and pfmdr 1 56Y point mutations in Plasmodium falciparum asymptomatic school children.

Results: A nested PCR amplifying the 18S small-subunit ribosomal RNA (SSU rRNA) gene of Plasmodium in 205 samples confirmed 76.1% of the isolates as asymptomatic P. falciparum infections, with a substantial proportion 22% of P. malariae infection. Among these, 3.6% were single P. malariae infections and 15.1% were P. falciparum and P. malariae mixed infections. Mixed P. falciparum and P. ovale infections were 2.0%. Of the 156 Plasmodium falciparum, positive samples by species-specific PCR, 107 samples with P. falciparum mono-infection were analyzed for the presence of drug resistant alleles pfcrt 76T and pfmdr1- Y 86. The prevalence of pfcrt 76T mutation (74.6%) was higher than that of the pfmdr1-Y86 mutation (25.4%). Logistic regression analysis of socio-demographic factors predicted no significant association between pfcrt 76T mutation with gender and communities.

Conclusions: The results indicated a high prevalence of P. malariae and mixed infection in the area under study. The high-level distribution of the pfcrtT76 observed in the study could be possibly attributed to the fact that CQ remained widely used at the community level more than 14 years after withdrawal.