Prevalence of the molecular marker of chloroquine resistance (pfcrt 76) in Nigeria 5 years after withdrawal of the drug as first-line antimalarial: A cross-sectional study

Background. In line with the World Health Organization (WHO) guideline on chloroquine (CQ) resistance, CQ was withdrawn as the first-line antimalarial drug in Nigeria in 2005 as a result of widespread resistance. It was expected that its sensitivity and clinical usefulness ould be restored with time. This study therefore aimed to determine the level of CQ resistance in Nigerian children aged less than 60 months. Methods. We monitored the resistance pattern 5 years after withdrawal of CQ, using the pfcrt K76T mutation as a molecular marker for CQ resistance. Results. Of 98 Plasmodium falciparum-positive blood samples, 95 (96.9%) showed the K76T mutation. Twenty-seven (27.6%) of the children had been treated with CQ at home before presentation at the clinic, while 50 (51.0%) had taken other antimalarials. Conclusion. Our results indicate that there is an urgent need to re-evaluate antimalarial drug policy in Nigeria, especially when 27.6% of our study population still use CQ at home despite its withdrawal as first-line antimalarial. This may require effective legislation against the manufacture, importation and use of CQ in Nigeria, if the purpose behind its withdrawal is to be achieved.