The lack of K13-propeller mutations associated with artemisinin resistance in Plasmodium falciparum in Democratic Republic of Congo (DRC)

Abstract Background. Loss of efficacy of malaria diagnostic tests may lead to untreated or mistreated cases, compromising case management and control. There is an increasing reliance on rapid diagnostic tests (RDTs), with the most widely used of these targeting the Plasmodium falciparum histidine-rich protein 2 gene. There are numerous reports of the deletion of this gene in P. falciparum parasites in some populations, rendering them undetectable by PfHRP2 RDTs. We aimed to identify P. falciparum parasites lacking the P. falciparum histidine rich protein 2 and 3 genes isolated from asymptomatic and symptomatic school-age children in Kinshasa, Democratic Republic of Congo. Methods. We assessed the performance of PfHRP2-based RDTs in comparison to microscopy and PCR. PCR was then used to identify parasite isolates lacking pfhrp2/3 genes. Results. Of 462 DNA samples analysed, deletions of the pfhrp2 and pfhrp3 genes were found in only three (2%) samples and one (1%) sample in the RDT positive subgroup, respectively. No parasites lacking the pfhrp2/3 genes were found in the RDT negative subgroup. Conclusion. Plasmodium falciparum histidine-rich protein 2/3 gene deletions are uncommon in the surveyed population, and do not result in diagnostic failure. We encourage the use of rigorous PCR methods to identify pfhrp2/3 gene deletions in order to minimize the overestimation of their prevalence.

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Assessment of Molecular Markers of Anti-malarial Drug Resistance in Pfk13-propeller, Pfcrt and Pfmdr1 Genes in Plasmodium Falciparum Isolated From Patients Returning for Malaria Retreatment in Democratic Republic of Congo

10.21203/rs.3.rs-87989/v1 ◽

2020 ◽

Author(s):

Doudou Malekita Yobi ◽

Nadine K. Kayiba ◽

Dieudonné M. Mvumbi ◽

Raphael Boreux ◽

Pius Z. Kabututu ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Molecular Markers ◽

Real Time ◽

Real Time Pcr ◽

Copy Number ◽

Democratic Republic ◽

Democratic Republic Of Congo ◽

First Line ◽

Pcr Assay ◽

Republic Of Congo

Abstract BackgroundThe Democratic Republic of Congo (DRC) malaria treatment policy recommends two first-line artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated malaria: Artesunate-amodiaquine (ASAQ) and Artemether-lumefantrine (AL). This study investigated resistance to the ACTs currently in use in DRC through molecular markers in pfk13, pfcrt and pfmdr1 genes in Plasmodium falciparum isolated from patients returning for malaria retreatment. MethodsFrom November 2018 to November 2019, dried blood spots were taken from patients returning to health structures for fever within 28 days after an initial malaria treatment in 6 sentinel sites of National Malaria Control Programme (NMCP) across DRC. The new episode of malaria was first detected by a rapid diagnostic test (RDT) and then confirmed by a real-time PCR assay. Fragments of interest in pfk13 and pfcrt genes were amplified by conventional PCR before sequencing and Pfmdr1 gene copy number was determined by a TaqMan real-time PCR assay. ResultsOut of 474 enrolled patients, 364 (76.8%) were confirmed positive by PCR for P. falciparum. Of the 325 P. falciparum isolates successfully sequenced in pfk13-propeller gene, 7 (2.2%) carried non-synonymous (NS) mutations among which 3 previously reported (N498I, N554K and A557S) and 4 not yet reported (F506L, E507V, D516E and G538S). Of the 335 isolates successfully sequenced in pfcrt gene, 139 (41.5%) harbored the K76T mutation known to be associated with CQ resistance. The SVMNT haplotype associated with resistance to AQ has not been found. None of the isolates carried increased copy number of pfmdr1 gene among the 322 P. falciparum isolates successfully analyzed.ConclusionNo molecular marker known to date as associated with resistance to first-line ACTs in use was detected in P. falciparum isolated in patients returning for retreatment. Regular monitoring through in vivo drug efficacy and molecular studies must continue to ensure the effectiveness of the treatment of malaria in DRC.

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Pfhrp2 -deleted Plasmodium falciparum parasites in the Democratic Republic of Congo: A national cross-sectional survey

The Journal of Infectious Diseases ◽

10.1093/infdis/jiw538 ◽

2016 ◽

pp. jiw538 ◽

Cited By ~ 14

Author(s):

Jonathan B. Parr ◽

Robert Verity ◽

Stephanie M. Doctor ◽

Mark Janko ◽

Kelly Carey-Ewend ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Democratic Republic ◽

Democratic Republic Of Congo ◽

Cross Sectional Survey ◽

Cross Sectional ◽

Republic Of Congo

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Household prevalence of P. falciparum, P. vivax, and P. ovale in the Democratic Republic of the Congo, 2013-2014

Clinical Infectious Diseases ◽

10.1093/cid/ciaa1772 ◽

2020 ◽

Author(s):

Cedar L Mitchell ◽

Hillary M Topazian ◽

Nicholas F Brazeau ◽

Molly Deutsch-Feldman ◽

Jeremie Muwonga ◽

...

Keyword(s):

Risk Factors ◽

Plasmodium Falciparum ◽

Democratic Republic ◽

Democratic Republic Of Congo ◽

Molecular Study ◽

Age Group ◽

Cross Sectional ◽

Republic Of Congo ◽

Republic Of The Congo

Abstract In a cross-sectional molecular study in the Democratic Republic of Congo, 78% of households had at least one member infected with Plasmodium falciparum, vivax, and/or ovale spp. 47% of children and 33% of adults tested positive for at least one species. Risk factors varied by species and age group.

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