Distribution of pfmdr1 and pfcrt chloroquine drug resistance alleles in north-western Nigeria.

Background In Nigeria, decline in the sensitivity of Plasmodium falciparum to Artemisinin Combination Therapy (ACT) has prompted the unofficial use of chloroquine (CQ) for self-medication. This study was designed to determine the prevalence and distribution of CQ resistant/susceptible alleles of CQ resistance transporter (Pfcrt) and P. falciparum multidrug resistance gene 1 (Pfmdr1) in view of the possible re-introduction of CQ for malaria treatment. Materials and methods Four hundred and sixty six (466) P. falciparum positive samples were randomly collected from five states of northwest Nigeria. The samples were amplified using RT- PCR at codon 76 for Pfcrt and codon 86 for Pfmdr1. Data was analysed using chi-square, odds ratios and paired t-tests. Results Drug susceptible alleles (N86) were most prevalent in the study population (47.9%; 223/466), followed by the drug resistance alleles 86Y (28.3%; 132/466), followed by the drug susceptible alleles K76 (17.4%; 81/466), the resistant alleles 76T (12.4%; 58/466) and finally the mixed infection mutation K76T (3.6%; 17/466). Differences between the distributions of the Pfmdr1 and Pfcrt alleles were significant (P<0.05). There were significant differences (P<0.05) between N86 and 86Y alleles, but no significant differences between K76 and 76T alleles, including the prevalence of the various alleles across the different age groups. Conclusion The results of this study suggest the possibility of (re)introducing CQ for malaria treatment in north-western Nigeria and provide insight in the genetic background of P. falciparum in the study area.