Contrasting Asymptomatic and Drug Resistance Gene Prevalence of <i>Plasmodium falciparum</i> in Ghana: Implications on Seasonal Malaria Chemoprevention

• Main Authors: Cheikh Cambel Dieng, Lauren Gonzalez, Kareen Pestana, Shittu B. Dhikrullahi, Linda E. Amoah, Yaw A. Afrane, Eugenia Lo
• Format: Article
• Language: English
• Published: MDPI AG 2019-07-01
• Series: Genes
• Subjects: <i>Plasmodium falciparum</i>; <i>pfdhps</i>; <i>phdhfr</i>; asymptomatic infections; antimalarial drug resistance; Sulfadoxine-Pyrimethamine; quantitative real-time PCR; TARE-2
• Online Access: https://www.mdpi.com/2073-4425/10/7/538

Malaria is a significant public health problem in Ghana. Seasonal Malaria Chemoprevention (SMC) using a combination of sulfadoxine-pyrimethamine and amodiaquine has been implemented since 2015 in northern Ghana where malaria transmission is intense and seasonal. In this study, we estimated the prevalence of asymptomatic <i>P. falciparum</i> carriers in three ecological zones of Ghana, and compared the sensitivity and specificity of different molecular methods in identifying asymptomatic infections. Moreover, we examined the frequency of mutations in <i>pfcrt</i>, <i>pfmdr1</i>, <i>pfdhfr</i>, and <i>pfdhps</i> that relate to the ongoing SMC. A total of 535 asymptomatic schoolchildren were screened by microscopy and PCR (18s rRNA and TARE-2) methods. Among all samples, 28.6% were detected as positive by 18S nested PCR, whereas 19.6% were detected by microscopy. A high PCR-based asymptomatic prevalence was observed in the north (51%) compared to in the central (27.8%) and south (16.9%). The prevalence of <i>pfdhfr</i>-N51I/C59R/S108N/<i>pfdhps</i>-A437G quadruple mutant associated with sulfadoxine-pyrimethamine resistance was significantly higher in the north where SMC was implemented. Compared to 18S rRNA, TARE-2 serves as a more sensitive molecular marker for detecting submicroscopic asymptomatic infections in high and low transmission settings. These findings establish a baseline for monitoring <i>P. falciparum</i> prevalence and resistance in response to SMC over time.