Geographical emergence of sulfadoxine-pyrimethamine drug resistance-associated P. falciparum and P. malariae alleles in co-existing Anopheles mosquito and asymptomatic human populations across Cameroon

• Published in: Antimicrobial agents and chemotherapy Vol. 67; no. 12; p. e0058823
• Main Authors: Nkemngo, Francis N, Raissa, Lymen W, Nguete, Daniel N, Ndo, Cyrille, Fru-Cho, Jerome, Njiokou, Flobert, Wanji, Samuel, Wondji, Charles S
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 14-12-2023
• Subjects: Antimicrobial Chemotherapy; Epidemiology and Surveillance; sulfadoxine-pyrimethamine; Cameroon; P. falciparum; Anopheles mosquitoes; P. malariae; drug resistance; humans
• ISSN: 0066-4804; 1098-6596
• DOI: 10.1128/aac.00588-23

Malaria molecular surveillance remains critical in detecting and tracking emerging parasite resistance to anti-malarial drugs. The current study employed molecular techniques to determine
species prevalence and characterize the genetic diversity of
and
molecular markers of sulfadoxine-pyrimethamine resistance in humans and wild
mosquito populations in Cameroon.
mosquito collections and parasitological survey were conducted in villages to determine
species infection, and genomic phenotyping of anti-folate resistance was accomplished by sequencing the dihydrofolate-reductase (
) and dihydropteroate-synthase (
) genes of naturally circulating
and
isolates. The malaria prevalence in Elende was 73.5% with the 5-15 years age group harboring significant
(27%) and
(19%) infections. The polymorphism breadth of the pyrimethamine-associated
marker revealed a near fixation (94%) of the triple-mutant -A
I
. The
backbone mediating sulfadoxine resistance reveals a high frequency of the
K
A
A
alleles (20.8%). Similarly, the
N
K
S
S
F
I
haplotype (78.4%) was predominantly detected in the asexual blood stage. In contrast, the
-
occured at 37.2% frequency. The combined quadruple N
K
S
S
F
I
_
K
A
A
(31.9%) was the major circulating haplotype with similar frequency in humans and mosquitoes. This study highlights the increasing frequency of the
parasite mostly common in asymptomatic individuals with apparent
infection. Interventions directed at reducing malaria transmission such as the scaling-up of SP are favoring the emergence and spread of multiple drug-resistant alleles between the human and mosquito host systems.