Current status of 4-aminoquinoline resistance markers 18 years after cessation of chloroquine use for the treatment of uncomplicated falciparum malaria in the littoral coastline region of Cameroon

ABSTRACT

The onset and rapid spread of chloroquine resistance and the introduction of amodiaquine for the treatment of uncomplicated malaria in Cameroon have influenced the proportion of Plasmodium falciparum sensitive and resistant alleles related to 4-aminoquinoline drugs. This study was undertaken to determine the prevalence of resistance markers to antimalarial 4-aminoquinolines in Douala in the Littoral Region, and Buea in the South West Region in June 2020. Dry blood spots were prepared from malaria microscopy positive cases and used for parasite DNA extraction by chelex-100 method. Plasmodium species identification was carried out by PCR amplification/agarose gel electrophoresis of 18srRNA. The Pfcrt and Pfmdr1 genes were amplified by PCR followed by restriction digestion. The prevalence of single nucleotide polymorphisms (SNPs) was compared between study sites and with previous studies carried out between 2003–2005 and 2009–2011 using the Chi square test. The results showed that Plasmodium falciparum was the dominant species occurring as mono-infections (84.6%). The wild type K76 allele of the Pfcrt gene was found in 74.9% of isolates while the wild N86, Y184 and D1246 alleles of the Pfmdr1 gene were found respectively in 87.2%, 89.6% and 100% of field isolates. The results showed a significant reduction in the mutant alleles compared to results obtained in 2003–2005 and 2009–2013. The KNYD haplotype was observed to be the most prevalent. The results indicated that there is a gradual erosion of the mutant Pfcrt and Pfmdr1 genotype and a gradual return to the sensitive P. falciparum genotype in Cameroon.

KEYWORDS:

• Plasmodium falciparum
• drug resistance
• pfmdr1
• 4-aminoquinoline
• pfcrt
• alleles
• buea

Acknowledgments

The authors are sincerely thankful to the authorities of the Bonassama Health District Hospital and the Laquintini Hospital in Douala as well as the Regional Hospital in Buea for their frank collaboration that led to the realization of this work. They are equally thankful to the patients who accepted to donate blood samples and data for the study. They acknowledge the Cell and Molecular Biology Laboratory for providing laboratory space and some reagents for the molecular analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Institutional review board statement

The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Ethics Review Committee of the Faculty of Health Science, University of Buea.

Informed consent statement

Prior to enrolment, written informed consent was obtained from all participants involved in this study. This included potential publication of study data.

Data Availability Statement

Data are contained within the article.

Additional information

Funding

This research was supported partially through the Malaria Research Capacity Development in West and Central Africa (MARCAD) Consortium. The MARCAD consortium is funded through a grant from the Developing Excellence in Leadership, Training and Science (DELTAS) Africa Initiative (grant # DEL-15–010) to the University of Yaoundé I. The DELTAS Africa Initiative is an independent funding scheme of the African Academy of Sciences (AAS)’s Alliance for Accelerating Excellence in Science in Africa (AESA) and supported by the New Partnership for Africa’s Development Planning and Coordinating Agency (NEPAD Agency) with funding from the Wellcome Trust (grant # Wellcome Trust (DELTAS Africa) 107741/A/15/Z) and the United Kingdom (UK) government. The views expressed in this publication are those of the authors and not necessarily those of AAS, NEPAD Agency, Wellcome Trust or the UK government.