ABSTRACT
BACKGROUND: Because of the loss of chloroquine (CQ) effectiveness, the Democratic Republic of Congo (DRC)'s malaria treatment policy replaced CQ by sulfadoxine-pyrimethamine (SP) as first-line treatment of uncomplicated malaria in 2003, which in turn was replaced by artemisinin-based combination therapies (ACT) in 2005. The World Health Organization (WHO) recommends monitoring of anti-malarial drug resistance every 2 years. The study aimed to provide baseline data for biennial molecular surveillance of anti-malarial drug resistance by comparing data from a study conducted in 2019 to previously published data from a similar study conducted in 2017 in the DRC. METHODS: From July to November 2019, a cross-sectional study was conducted in ten sites which were previously selected for a similar study conducted in 2017 across the DRC. P. falciparum malaria was diagnosed by a rapid diagnostic test (RDT) or by microscopy and dried blood samples (DBS) were taken from patients who had a positive test. Segments of interest in pfcrt and pfk13 genes were amplified by conventional PCR before sequencing. RESULTS: Out of 1087 enrolled patients, 906 (83.3%) were PCR-confirmed for P. falciparum. Like in the 2017-study, none of the mutations known to be associated with Artemisinine (ART) resistance in Southeast Asia was detected. However, non-synonymous (NS) mutations with unknown functions were observed among which, A578S was detected in both 2017 and 2019-studies. The overall prevalence of pfcrt-K76T mutation that confers CQ-resistance was 22.7% in 2019-study compared to 28.5% in 2017-study (p-value = 0.069), but there was high variability between sites in the two studies. Like in 2017-study, the pfcrt 72-76 SVMNT haplotype associated with resistance to amodiaquine was not detected. CONCLUSION: The study reported, within 2 years, the non-presence of molecular markers currently known to be associated with resistance to ART and to AQ in P. falciparum isolated in the DRC. However, the presence of polymorphisms with as-yet unknown functions was observed, requiring further characterization. Moreover, an overall decrease in the prevalence of CQ-resistance marker was observed in the DRC, but this prevalence remained highly variable from region to region.
Subject(s)
Antimalarials , Malaria, Falciparum , Antimalarials/pharmacology , Antimalarials/therapeutic use , Cross-Sectional Studies , Democratic Republic of the Congo/epidemiology , Drug Combinations , Drug Resistance/genetics , Humans , Malaria, Falciparum/drug therapy , Malaria, Falciparum/epidemiology , Plasmodium falciparum/genetics , Protozoan Proteins/geneticsABSTRACT
BACKGROUND: The national policy for malaria treatment of the Democratic Republic of Congo recommends two first-line artemisinin-based combinations for the treatment of uncomplicated malaria: artesunate-amodiaquine and artemether-lumefantrine. This study investigated the presence of markers associated with resistance to the current first-line artemisinin-based combination therapy (ACT) in isolates of Plasmodium falciparum from treatment failure patients in the Democratic Republic of Congo. METHODS: From November 2018 to November 2019, dried blood spots were taken from patients returning to health centres for fever within 28 days after an initial malaria treatment in six sentinel sites of the National Malaria Control Programme across Democratic Republic of Congo. The new episode of malaria was first detected by a rapid diagnostic test and then confirmed by a real-time PCR assay to define treatment failure. Fragments of interest in pfk13 and pfcrt genes were amplified by conventional PCR before sequencing and the Pfmdr1 gene copy number was determined by a TaqMan real-time PCR assay. RESULTS: Out of 474 enrolled patients, 364 (76.8%) were confirmed positive by PCR for a new episode of P. falciparum malaria, thus considered as treatment failure. Of the 325 P. falciparum isolates obtained from 364 P. falciparum-positive patients and successfully sequenced in the pfk13-propeller gene, 7 (2.2%) isolates carried non-synonymous mutations, among which 3 have been previously reported (N498I, N554K and A557S) and 4 had not yet been reported (F506L, E507V, D516E and G538S). Of the 335 isolates successfully sequenced in the pfcrt gene, 139 (41.5%) harboured the K76T mutation known to be associated with chloroquine resistance. The SVMNT haplotype associated with resistance to amodiaquine was not found. None of the isolates carried an increased copy number of the pfmdr1 gene among the 322 P. falciparum isolates successfully analysed. CONCLUSION: No molecular markers currently known to be associated with resistance to the first-line ACT in use were detected in isolates of P. falciparum from treatment failure patients. Regular monitoring through in vivo drug efficacy and molecular studies must continue to ensure the effectiveness of malaria treatment in Democratic Republic of Congo.
Subject(s)
Amodiaquine/pharmacology , Antimalarials/pharmacology , Artemether, Lumefantrine Drug Combination/pharmacology , Artemisinins/pharmacology , Drug Resistance/genetics , Membrane Transport Proteins/genetics , Multidrug Resistance-Associated Proteins/genetics , Plasmodium falciparum/genetics , Protozoan Proteins/genetics , Adolescent , Adult , Aged , Child , Child, Preschool , Democratic Republic of the Congo , Drug Combinations , Female , Genetic Markers/genetics , Humans , Infant , Infant, Newborn , Male , Middle Aged , Treatment Failure , Young AdultABSTRACT
BACKGROUND: The loss of chloroquine (CQ) effectiveness has led to its withdrawal from national policies as a first-line treatment for uncomplicated malaria in several endemic countries, such as the Democratic Republic of Congo (DRC). The K76T mutation on the pfcrt gene has been identified as a marker of CQ resistance and the SVMNT haplotype in codons 72-76 on the same gene has been associated with resistance to amodiaquine (AQ). In the DRC, the prevalence of K76T has decreased from 100% in 2000 to 63.9% in 2014. The purpose of this study was to determine the prevalence of K76T mutations in circulating strains of Plasmodium falciparum, 16 years after CQ withdrawal in the DRC and to investigate the presence of the SVMNT haplotype. METHODS: In 2017, ten geographical sites across the DRC were selected. Dried blood samples were collected from patients attending health centres. Malaria was first detected by a rapid diagnostic test (RDT) available on site (SD Bioline Malaria Ag Pf or CareStart Malaria Pf) or thick blood smear and then confirmed by a P. falciparum species-specific real-time PCR assay. A pfcrt gene segment containing a fragment that encodes amino acids at positions 72-76 was amplified by conventional PCR before sequencing. RESULTS: A total of 1070 patients were enrolled. Of the 806 PCR-confirmed P. falciparum positive samples, 764 were successfully sequenced. The K76T mutation was detected in 218 samples (28.5%; 95% CI 25.4%-31.9%), mainly (96%) with the CVIET haplotype. Prevalence of CQ resistance marker was unequally distributed across the country, ranging from 1.5% in Fungurume to 89.5% in Katana. The SVMNT haplotype, related to AQ resistance, was not detected. CONCLUSION: Overall, the frequency of the P. falciparum CQ resistance marker has decreased significantly and no resistance marker to AQ was detected in the DRC in 2017. However, the between regions variability of CQ resistance remains high in the country. Further studies are needed for continuous monitoring of the CQ resistance level for its prospective re-use in malaria management. The absence of the AQ resistance marker is in line with the use of this drug in the current DRC malaria treatment policy.
Subject(s)
Amodiaquine/therapeutic use , Antimalarials/therapeutic use , Chloroquine/therapeutic use , Drug Resistance/genetics , Malaria, Falciparum/drug therapy , Membrane Transport Proteins/genetics , Protozoan Proteins/genetics , Adolescent , Adult , Aged , Child , Child, Preschool , Democratic Republic of the Congo/epidemiology , Dried Blood Spot Testing , Humans , Infant , Infant, Newborn , Malaria, Falciparum/epidemiology , Mass Screening , Middle Aged , Mutation , Plasmodium falciparum/genetics , Polymorphism, Genetic , Prospective Studies , Young AdultABSTRACT
Contexte et objectifs. La République Démocratique du Congo compte parmi les pays à lourd fardeau pour la tuberculose (TB), l'incidence réelle de la maladie n'est pas formellement connue. La présente étude vise à décrire les tendances de l'incidence notifiée des patients atteints de tuberculose pulmonaire bactériologiquement confirmée (TP+) et leurs issues thérapeutiques. Méthodes. Cette étude documentaire, analyse les données des patients diagnostiqués et traités pour tuberculose de 2007 à 2017 en RDC. L'incidence notifiée des patients TP+, le taux d'accroissement annuel, les issues thérapeutiques ont été recherchés. Les variations du nombre de patients sont exprimées par les proportions. Les tendances sont présentées à travers les courbes de régression linéaire. Les issues thérapeutiques sont comparées à l'aide du z-score avec un seuil significatif de pË 0,05. Résultats. Au total 884 458 patients TP+ ont été rapportés, dont 820 858 nouveaux patients (NP TP+) et 63 600 déjà traités. Le taux d'accroissement au cours de cette décade était de 28,95%, soit de 66099 en 2007 à 93767 en 2017 pour les NP TP+. L'augmentation annuelle moyenne était de 2,41% +/- 3,28 pour les NP TP+ et de 5,7% +/- 0,26 par an pour les rechutes. La notification des échecs de traitement initial et repris après abandon de traitement ont une tendance à la baisse. L'évaluation thérapeutique de tous les cas cumulés a concerné 848 163 patients dont 789 716 NP TP+ et 58447 en retraitement. Le succès thérapeutique était de 88,0 % pour les NP TP+ et 70,0 % pour les rechutes, de 64,3 % pour les échecs et de 67,8% pour les repris en traitement après abandon. En somme 70 515 (8,3%) patients ont gardé des expectorations positives. Conclusion. Cette étude montre une tendance à la hausse de notification des cas incidents dont l'issue de traitement répond aux standards de l'OMS. En outre, un nombre des personnes demeurent porteurs de germes persistants précurseurs d'une TB pharmacorésistante acquise
Subject(s)
Democratic Republic of the Congo , Tuberculosis, Pulmonary/drug therapy , Tuberculosis, Pulmonary/therapyABSTRACT
Contexte et objectifs. La République Démocratique du Congo compte parmi les pays à lourd fardeau pour la tuberculose (TB), l'incidence réelle de la maladie n'est pas formellement connue. La présente étude vise à décrire les tendances de l'incidence notifiée des patients atteints de tuberculose pulmonaire bactériologiquement confirmée (TP+) et leurs issues thérapeutiques. Méthodes. Cette étude documentaire, analyse les données des patients diagnostiqués et traités pour tuberculose de 2007 à 2017 en RDC. L'incidence notifiée des patients TP+, le taux d'accroissement annuel, les issues thérapeutiques ont été recherchés. Les variations du nombre de patients sont exprimées par les proportions. Les tendances sont présentées à travers les courbes de régression linéaire. Les issues thérapeutiques sont comparées à l'aide du z-score avec un seuil significatif de pË 0,05. Résultats. Au total 884 458 patients TP+ ont été rapportés, dont 820 858 nouveaux patients (NP TP+) et 63 600 déjà traités. Le taux d'accroissement au cours de cette décade était de 28,95%, soit de 66099 en 2007 à 93767 en 2017 pour les NP TP+. L'augmentation annuelle moyenne était de 2,41% +/- 3,28 pour les NP TP+ et de 5,7% +/- 0,26 par an pour les rechutes. La notification des échecs de traitement initial et repris après abandon de traitement ont une tendance à la baisse. L'évaluation thérapeutique de tous les cas cumulés a concerné 848 163 patients dont 789 716 NP TP+ et 58447 en retraitement. Le succès thérapeutique était de 88,0 % pour les NP TP+ et 70,0 % pour les rechutes, de 64,3 % pour les échecs et de 67,8% pour les repris en traitement après abandon. En somme 70 515 (8,3%) patients ont gardé des expectorations positives. Conclusion. Cette étude montre une tendance à la hausse de notification des cas incidents dont l'issue de traitement répond aux standards de l'OMS. En outre, un nombre des personnes demeurent porteurs de germes persistants précurseurs d'une TB pharmacorésistante acquise
