High Frequency of Pfcrt-76T Allele in Plasmodium falciparum Isolates From Gabon and Ivory Coast After the Withdrawal of Chloroquine.

The aim of this study was to assess the proportion of Pfcrt-76T mutant allele four years after the adoption of new malaria control guidelines in Gabon and Ivory Coast. Frequency of K76T mutation of Pfcrt gene was compared between Plasmodium falciparum isolates from Gabon and Ivory Coast. Samples were collected in 2008 in Gabon and in 2009 in Ivory Coast. In total, 151 isolates were selected and analysed by nested-PCR-RFLP for Pfcrt-76 allele identification: 63 in Abobo (Ivory Coast) and 78 in Oyem (Gabon). The proportion of Pfcrt-76T mutant allele was higher in Oyem (70%) compared to Abobo (46%) (p=0.005). This allele was more frequently detected in patients less than 5 years old in Oyem (75 %) compared to Abobo (52%) (p<0.01). The present work showed different prevalence of Pfcrt-76T allele between both sites probably due to a different drug pressure on P. falciparum strains circulating in these areas. Moreover, a decrease of the mutation frequency is observed compared to data obtained in 2005. Therefore, a continuous monitoring of this allele and other drug resistance molecular markers is required in these countries.