The landscape of drug resistance in Plasmodium falciparum malaria in the Democratic Republic of Congo: a mapping systematic review.

CONTEXT: The Democratic Republic of Congo (DRC), one of the most malaria-affected countries worldwide, is a potential hub for global drug-resistant malaria. This study aimed at summarizing and mapping surveys of malaria parasites carrying molecular markers of drug-resistance across the country. METHODS: A systematic mapping review was carried out before July 2023 by searching for relevant articles through seven databases (PubMed, Embase, Scopus, African Journal Online, African Index Medicus, Bioline and Web of Science). RESULTS: We identified 1541 primary studies of which 29 fulfilled inclusion criteria and provided information related to 6385 Plasmodium falciparum clinical isolates (collected from 2000 to 2020). We noted the PfCRT K76T mutation encoding for chloroquine-resistance in median 32.1% [interquartile interval, IQR: 45.2] of analyzed malaria parasites. The proportion of parasites carrying this mutation decreased overtime, but wide geographic variations persisted. A single isolate had encoded the PfK13 R561H substitution that is invoked in artemisinin-resistance emergence in the Great Lakes region of Africa. Parasites carrying various mutations linked to resistance to the sulfadoxine-pyrimethamine combination were widespread and reflected a moderate resistance profile (PfDHPS A437G: 99.5% [IQR: 3.9]; PfDHPS K540E: 38.9% [IQR: 47.7]) with median 13.1% [IQR: 10.3] of them being quintuple IRN-GE mutants (i.e., parasites carrying the PfDHFR N51I-C59R-S108N and PfDHPS A437G-K540E mutations). These quintuple mutants tended to prevail in eastern regions of the country. Among circulating parasites, we did not record any parasites harboring mutations related to mefloquine-resistance, but we could suspect those with decreased susceptibility to quinine, amodiaquine, and lumefantrine based on corresponding molecular surrogates. CONCLUSIONS: Drug resistance poses a serious threat to existing malaria therapies and chemoprevention options in the DRC. This review provides a baseline for monitoring public health efforts as well as evidence for decision-making in support of national malaria policies and for implementing regionally tailored control measures across the country.

Evaluation of the usefulness of intermittent preventive treatment of malaria in pregnancy with sulfadoxine-pyrimethamine in a context with increased resistance of Plasmodium falciparum in Kingasani Hospital, Kinshasa in the Democratic Republic of Congo.

BACKGROUND: Increasing resistance of Plasmodium falciparum to sulfadoxine-pyrimethamine (SP) threatens its usefulness for intermittent preventive treatment in pregnancy (IPTp-SP). The prophylactic effects of IPTp-SP on maternal malaria and adverse pregnancy outcomes were evaluated in Kingasani Hospital, Kinshasa in the Democratic Republic of Congo (DRC). METHODS: Laboring women (n = 844) and respective newborns were investigated. Blood samples collected from women were tested for malaria using rapid diagnostic test (RDT), blood smears examination, and real-time PCR. The hemoglobin level was measured by HemoCue© analyzer. A PCR-RFLP method was applied for detecting N51I, C59R, and S108N mutations on dhfr along with A437G and K540E mutations on dhps in P. falciparum positive samples. Logistic regression models assessed relationships between IPTp-SP uptake and pregnancy outcomes. RESULTS: P. falciparum malaria was detected at delivery in 10.8% of women and was statistically associated with fever during the pregnancy (OR = 2.9 [1.5; 6.3]; p = 0.004) and maternal anemia (OR = 3.9 [2.4; 6.3]; p < 0.001). One out of five parasites was a quintuple mutant encoding dhfr mutations 51I, 59R, and 108 N along with dhps mutations 437G and 540E. The molecular profile of parasites (i.e., 32.6% of parasites carrying dhps K540E) was suitable with continued use of SP for IPTp. IPTp-SP uptake was not associated with reduced maternal malaria, fever reported in pregnancy, or fetal deaths (p > 0.05). Conversely, three or more doses of SP were associated with reduced maternal anemia at delivery (OR = 0.4 [0.2; 0.9]; p = 0.024), shortened gestation (OR = 0.4 [0.2; 0.8]; p = 0.009), and low-birth weights (OR = 0.2 [0.1; 0.5]; p < 0.001). CONCLUSION: IPTp-SP was not associated with reduced maternal malaria in our study, but evidence was found of a prophylactic effect against adverse pregnancy outcomes. To counteract further loss of clinical effects of IPTp-SP in the study population, alternative strategies able to improve its anti-malarial efficacy such as combination of SP with partner molecules should be implemented.

Care-seeking behaviour and socio-economic burden associated with uncomplicated malaria in the Democratic Republic of Congo.

BACKGROUND: This study aimed to estimate the socio-economic costs of uncomplicated malaria and to explore health care-seeking behaviours that are likely to influence these costs in the Democratic Republic of Congo (DRC), a country ranked worldwide as the second most affected by malaria. METHODS: In 2017, a cross-sectional survey included patients with uncomplicated malaria in 64 healthcare facilities from 10 sentinel sites of the National Malaria Control Programme (NMCP) in the DRC. A standard questionnaire was used to assess health care-seeking behaviours of patients. Health-related quality of life (HRQL) and disutility weights (DW) of illness were evaluated by using the EuroQol Group's descriptive system (EQ-5D-3L) and its visual analogue scale (EQ VAS). Malaria costs were estimated from a patient's perspective. Probabilistic sensitivity analyses (PSA) evaluated the uncertainty around the cost estimates. Generalized regression models were fitted to assess the effect of potential predictive factors on the time lost and the DW during illness. RESULTS: In total, 1080 patients (age: 13.1 ± 14 years; M/F ratio: 1.1) were included. The average total costs amounted to US$ 36.3 [95% CI 35.5-37.2] per malaria episode, including US$ 16.7 [95% CI 16.3-17.1] as direct costs and US$ 19.6 [95% CI 18.9-20.3] indirect costs. During care seeking, economically active patients and their relatives lost respectively 3.3 ± 1.8 and 3.4 ± 2.1 working days. This time loss occurred mostly at the pre-hospital stage and was the parameter associated the most with the uncertainty around malaria cost estimates. Patients self-rated an average 0.36 ± 0.2 DW and an average 0.62 ± 0.3 EQ-5D index score per episode. A lack of health insurance coverage (896 out of 1080; 82.9%) incurred substantially higher costs, lower quality of life, and heavier DW while leading to longer time lost during illness. Residing in rural areas incurred a disproportionally higher socioeconomic burden of uncomplicated malaria with longer time lost due to illness and limited access to health insurance mechanisms. CONCLUSION: Uncomplicated malaria is associated with high economic costs of care in the DRC. Efforts to reduce the cost-of-illness should target time lost at the pre-hospital stage and social disparities in the population, while reinforcing measures for malaria control in the country.

Assessment of pfcrt 72-76 haplotypes eight years after chloroquine withdrawal in Kinshasa, Democratic Republic of Congo.

BACKGROUND: In 2001, the World Health Organization (WHO) has recommended the use of artemisinin-based combination therapy (ACT) as the first-line treatment of uncomplicated malaria cases, as monotherapies had become ineffective in many parts of the world. As a result, the Democratic Republic of Congo (DRC) withdrew chloroquine (CQ) from its malaria treatment policy in 2002 and an artesunate (AS)-amodiaquine (AQ) combination became the ACT of choice in DRC in 2005. AQ-resistance (AQR) has been reported in several parts of the world and mutations in codons 72-76 of the Plasmodium falciparum chloroquine-resistance transporter (pfcrt) gene have been strongly correlated with resistance, especially mutations encoding the SVMNT haplotype. This haplotype was first identified in Southeast Asia and South America but was recently reported in two African countries neighbouring DRC. These facts raised two questions: the first about the evolution of CQ resistance (CQR) in DRC and the second about the presence of the SVMNT haplotype, which would compromise the use of AQ as a partner drug for ACT. METHODS: A total of 213 thick blood films were randomly collected in 2010 from a paediatric clinic in Kinshasa, DRC. Microscopy controls and real-time polymerase chain reaction (RT-PCR) were performed for Plasmodium species identification. Haplotypes of the pfcrt gene were determined by sequencing. RESULTS: The K76T mutation was detected in 145 out of 198 P. falciparum-positive samples (73.2%). In these 145 resistant strains, only the CVIET haplotype was detected. CONCLUSIONS: This study is the first to assess the molecular markers of resistance to CQ and AQ after the introduction of ACT in DRC. The results suggest first that CQR is decreasing, as wild-type pfcrt haplotypes were found in only 26.8% of the samples and secondly that the SVMNT haplotype is not yet present in Kinshasa, suggesting that AQ remains valid as a partner drug for ACT in this region.

In vitro antiplasmodial activity of plants used in Benin in traditional medicine to treat malaria.

AIM OF THE STUDY: The aim of the study was to evaluate the in vitro antiplasmodial activity of crude extracts of 12 plant species traditionally used in Benin for the treatment of malaria in order to validate their use. MATERIALS AND METHODS: For each species, dichloromethane, methanol and total aqueous extracts were tested. The antiplasmodial activity of extracts was evaluated using the measurement of the plasmodial lactate dehydrogenase activity on chloroquine-sensitive (3D7) and resistant (W2) strains of Plasmodium falciparum. The selectivity of the different extracts was evaluated using the MTT test on J774 macrophage-like murine cells and WI38 human normal fibroblasts. RESULTS: The best growth inhibition of both strains of Plasmodium falciparum was observed with the dichloromethane extracts of Acanthospermum hispidum DC. (Asteraceae) (IC(50)=7.5 microg/ml on 3D7 and 4.8 microg/ml on W2), Keetia leucantha (K. Krause) Bridson (syn. Plectronia leucantha Krause) (Rubiaceae) leaves and twigs (IC(50)=13.8 and 11.3 microg/ml on 3D7 and IC(50)=26.5 and 15.8 microg/ml on W2, respectively), Carpolobia lutea G.Don. (Polygalaceae) (IC(50)=19.4 microg/ml on 3D7 and 8.1 microg/ml on W2) and Strychnos spinosa Lam. (Loganiaceae) leaves (IC(50)=15.6 microg/ml on 3D7 and 8.9 microg/ml on W2). All these extracts had a low cytotoxicity. CONCLUSION: Our study gives some justifications for the traditional uses of some investigated plants.