Efficacy and safety of artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in mainland Tanzania, 2018.

BACKGROUND: The use of artemisinin-based combination therapy (ACT) is recommended by the World Health Organization for the treatment of uncomplicated falciparum malaria. Artemether-lumefantrine (AL) is the most widely adopted first-line ACT for uncomplicated malaria in sub-Saharan Africa (SSA), including mainland Tanzania, where it was introduced in December 2006. The WHO recommends regular assessment to monitor the efficacy of the first-line treatment specifically considering that artemisinin partial resistance was reported in Greater Mekong sub-region and has been confirmed in East Africa (Rwanda and Uganda). The main aim of this study was to assess the efficacy and safety of AL for the treatment of uncomplicated falciparum malaria in mainland Tanzania. METHODS: A single-arm prospective anti-malarial drug efficacy trial was conducted in Kibaha, Mlimba, Mkuzi, and Ujiji (in Pwani, Morogoro, Tanga, and Kigoma regions, respectively) in 2018. The sample size of 88 patients per site was determined based on WHO 2009 standard protocol. Participants were febrile patients (documented axillary temperature ≥ 37.5 °C and/or history of fever during the past 24 h) aged 6 months to 10 years. Patients received a 6-dose AL regimen by weight twice a day for 3 days. Clinical and parasitological parameters were monitored during 28 days of follow-up to evaluate the drug efficacy and safety. RESULTS: A total of 653 children were screened for uncomplicated malaria and 349 (53.7%) were enrolled between April and August 2018. Of the enrolled children, 345 (98.9%) completed the 28 days of follow-up or attained the treatment outcomes. There were no early treatment failures, but recurrent infections were higher in Mkuzi (35.2%) and Ujiji (23%). By Kaplan-Meier analysis of polymerase chain reaction (PCR) uncorrected adequate clinical and parasitological response (ACPR) ranged from 63.4% in Mkuzi to 85.9% in Mlimba, while PCR-corrected ACPR on day 28 varied from 97.6% in Ujiji to 100% in Mlimba. The drug was well tolerated; the commonly reported adverse events were cough, runny nose, and abdominal pain. No serious adverse event was reported. CONCLUSION: This study showed that AL had adequate efficacy and safety for the treatment of uncomplicated falciparum malaria. The high number of recurrent infections were mainly due to new infections, indicating the necessity of utilizing alternative artemisinin-based combinations, such as artesunate amodiaquine, which provide a significantly longer post-treatment prophylactic effect.

Efficacy and safety of artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in mainland Tanzania, 2019.

BACKGROUND: Artemisinin-based combination therapy (ACT) has been a major contributor to the substantial reductions in global malaria morbidity and mortality over the last decade. In Tanzania, artemether-lumefantrine (AL) was introduced as the first-line treatment for uncomplicated Plasmodium falciparum malaria in 2006. The World Health Organization (WHO) recommends regular assessment and monitoring of the efficacy of the first-line treatment, specifically considering that artemisinin resistance has been confirmed in the Greater Mekong sub-region. This study's main aim was to assess the efficacy and safety of AL for treating uncomplicated P. falciparum malaria in Tanzania. METHODS: This was a single-arm prospective antimalarial drug efficacy trial conducted in four of the eight National Malaria Control Programme (NMCP) sentinel sites in 2019. The trial was carried out in outpatient health facilities in Karume-Mwanza region, Ipinda-Mbeya region, Simbo-Tabora region, and Nagaga-Mtwara region. Children aged six months to 10 years with microscopy confirmed uncomplicated P. falciparum malaria who met the inclusion criteria were recruited based on the WHO protocol. The children received AL (a 6-dose regimen of AL twice daily for three days). Clinical and parasitological parameters were monitored during follow-up over 28 days to evaluate drug efficacy. RESULTS: A total of 628 children were screened for uncomplicated malaria, and 349 (55.6%) were enrolled between May and September 2019. Of the enrolled children, 343 (98.3%) completed the 28-day follow-up or attained the treatment outcomes. There were no early treatment failures; recurrent infections during follow-up were common at two sites (Karume 29.5%; Simbo 18.2%). PCR-corrected adequate clinical and parasitological response (ACPR) by survival analysis to AL on day 28 of follow-up varied from 97.7% at Karume to 100% at Ipinda and Nagaga sites. The commonly reported adverse events were cough, skin pallor, and abdominal pain. The drug was well tolerated, and no serious adverse event was reported. CONCLUSION: This study showed that AL had adequate efficacy and safety for the treatment of uncomplicated falciparum malaria in Tanzania in 2019. The high recurrent infections were mainly due to new infections, highlighting the potential role of introducing alternative artemisinin-based combinations that offer improved post-treatment prophylaxis, such as artesunate-amodiaquine (ASAQ).

Therapeutic response to four artemisinin-based combination therapies in Angola, 2021.

Monitoring antimalarial efficacy is important to detect the emergence of parasite drug resistance. Angola conducts in vivo therapeutic efficacy studies (TESs) every 2 years in its fixed sentinel sites in Benguela, Lunda Sul, and Zaire provinces. Children with uncomplicated Plasmodium falciparum malaria were treated with artemether-lumefantrine (AL), artesunate-amodiaquine (ASAQ), dihydroartemisinin-piperaquine (DP), or artesunate-pyronaridine (ASPY) and followed for 28 (AL and ASAQ) or 42 days (DP and ASPY) to assess clinical and parasitological response to treatment. Two drugs were sequentially assessed in each site in February-July 2021. The primary indicator was the Kaplan-Meier estimate of the PCR-corrected efficacy at the end of the follow-up period. A total of 622 patients were enrolled in the study and 590 (95%) participants reached a study endpoint. By day 3, ≥98% of participants were slide-negative in all study sites and arms. After PCR correction, day 28 AL efficacy was 88.0% (95% CI: 82%-95%) in Zaire and 94.7% (95% CI: 90%-99%) in Lunda Sul. For ASAQ, day 28 efficacy was 92.0% (95% CI: 87%-98%) in Zaire and 100% in Lunda Sul. Corrected day 42 efficacy was 99.6% (95% CI: 99%-100%) for ASPY and 98.3% (95% CI: 96%-100%) for DP in Benguela. High day 3 clearance rates suggest no clinical evidence of artemisinin resistance. This was the fourth of five rounds of TES in Angola showing a corrected AL efficacy <90% in a site. For Zaire, AL has had an efficacy <90% in 2013, 2015, and 2021. ASAQ, DP, and ASPY are appropriate choices as artemisinin-based combination therapies in Angola.

Systematic Review and Meta-Analysis of Seasonal Malaria Chemoprevention.

Seasonal malaria chemoprevention (SMC) for children under 5 years of age for up to four monthly cycles during malaria transmission season was recommended by the WHO in 2012 and has been implemented in 13 countries in the Sahel, reaching more than 30 million children annually. Malaria control programs implementing SMC have asked the WHO to consider expanding the age range or number of monthly cycles. We conducted a systematic review and meta-analysis of SMC among children up to 15 years of age and up to six monthly cycles. Twelve randomized studies were included, with outcomes stratified by age (< 5/≥ 5 years), by three or four versus five or six cycles, and by drug where possible. Drug regimens included sulfadoxine-pyrimethamine + amodiaquine, amodiaquine-artesunate, and sulfadoxine-pyrimethamine + artesunate. Included studies were all conducted in Sahelian countries in which high-grade resistance to sulfadoxine-pyrimethamine was rare and in zones with parasite prevalence ranging from 1% to 79%. Seasonal malaria chemoprevention resulted in substantial reductions in uncomplicated malaria incidence measured during that transmission season (rate ratio: 0.27, 95% CI: 0.25-0.29 among children < 5 years; rate ratio: 0.27, 95% CI: 0.25-0.30 among children ≥ 5 years) and in the prevalence of malaria parasitemia measured within 4-6 weeks from the final SMC cycle (risk ratio: 0.38, 95% CI: 0.34-0.43 among children < 5 years; risk ratio: 0.23, 95% CI: 0.11-0.48 among children ≥ 5 years). In high-transmission zones, SMC resulted in a moderately reduced risk of any anemia (risk ratio: 0.77, 95% CI: 0.72-0.83 among children < 5 years; risk ratio: 0.70, 95% CI: 0.52-0.95 among children ≥ 5 years [one study]). Children < 10 years of age had a moderate reduction in severe malaria (risk ratio: 0.53, 95% CI: 0.37-0.76) but no evidence of a mortality reduction. The evidence suggests that in areas in which sulfadoxine-pyrimethamine and amodiaquine remained efficacious, SMC effectively reduced malaria disease burden among children both < 5 and ≥ 5 years old and that the number of cycles should be commensurate with the length of the transmission season, up to six cycles.

Variation in neutrophil levels and artemisinin-based combination therapy efficacy in West-Africa.

INTRODUCTION: Polymorphonuclear neutrophils (PMN) are involved in pathogen clearance by phagocytosis. However, the role of PMNs in the efficacy of artemisinin-based combination therapy (ACT) is poorly understood. METHODOLOGY: In a prospective longitudinal in vivo study, neutrophil rates were compared with malaria carriage after treatment with different ACTs: Artemether - lumefantrine (AL), Artesunate - amodiaquine (ASAQ), Dihydroartemisinin - piperaquine (DP) or Pyronaridine artesunate (PA). The study cases were classified as having neutropenia, normal neutrophil levels or neutrophilia depending on the level of neutrophils in the blood. This study included 3148 patients and was analyzed using R. RESULTS: On day 7, only four patients in the neutropenia group and treated with AL had a malaria positive blood smear based on microscopy. On day 28, the rate of recurrent parasitemia in the AL arm was significantly higher in neutropenia patients (50.9%) than in patients with normal rates of neutrophils (43.1%) or in those with neutrophilia (6.0%) (p < 0.001). In ASAQ arm, the rate of recurrent Plasmodium falciparum parasitemia was 58.8% in the neutropenia group versus 29.4% in patients with normal rates of neutrophils and 11.8% in patients with neutrophilia (p < 0.001). No patient treated with DP with normal neutrophil counts or neutrophilia was carrying malaria parasites on day 28. Among the 15 patients with parasitemia on day 28 in the PA arm, 11 (73.33%) had neutropenia while 4 (26.67%) had a normal neutrophil count (p < 0.001). CONCLUSIONS: Patients with neutropenia had higher rates of recurrent P. falciparum parasitemia after ACT.

Increasing Prevalence of Artemisinin-Resistant HRP2-Negative Malaria in Eritrea.

BACKGROUND: Although the clinical efficacy of antimalarial artemisinin-based combination therapies in Africa remains high, the recent emergence of partial resistance to artemisinin in Plasmodium falciparum on the continent is troubling, given the lack of alternative treatments. METHODS: In this study, we used data from drug-efficacy studies conducted between 2016 and 2019 that evaluated 3-day courses of artemisinin-based combination therapy (artesunate-amodiaquine or artemether-lumefantrine) for uncomplicated malaria in Eritrea to estimate the percentage of patients with day-3 positivity (i.e., persistent P. falciparum parasitemia 3 days after the initiation of therapy). We also assayed parasites for mutations in Pfkelch13 as predictive markers of partial resistance to artemisinin and screened for deletions in hrp2 and hrp3 that result in variable performance of histidine rich protein 2 (HRP2)-based rapid diagnostic tests for malaria. RESULTS: We noted an increase in the percentage of patients with day-3 positivity from 0.4% (1 of 273) in 2016 to 1.9% (4 of 209) in 2017 and 4.2% (15 of 359) in 2019. An increase was also noted in the prevalence of the Pfkelch13 R622I mutation, which was detected in 109 of 818 isolates before treatment, from 8.6% (24 of 278) in 2016 to 21.0% (69 of 329) in 2019. The odds of day-3 positivity increased by a factor of 6.2 (95% confidence interval, 2.5 to 15.5) among the patients with Pfkelch13 622I variant parasites. Partial resistance to artemisinin, as defined by the World Health Organization, was observed in Eritrea. More than 5% of the patients younger than 15 years of age with day-3 positivity also had parasites that carried Pfkelch13 R622I. In vitro, the R622I mutation conferred a low level of resistance to artemisinin when edited into NF54 and Dd2 parasite lines. Deletions in both hrp2 and hrp3 were identified in 16.9% of the parasites that carried the Pfkelch13 R622I mutation, which made them potentially undetectable by HRP2-based rapid diagnostic tests. CONCLUSIONS: The emergence and spread of P. falciparum lineages with both Pfkelch13-mediated partial resistance to artemisinin and deletions in hrp2 and hrp3 in Eritrea threaten to compromise regional malaria control and elimination campaigns. (Funded by the Bill and Melinda Gates Foundation and others; Australian New Zealand Clinical Trials Registry numbers, ACTRN12618001223224, ACTRN12618000353291, and ACTRN12619000859189.).

Provider and User Acceptability of Integrated Treatment for the Control of Malaria and Helminths in Saraya, South-Eastern Senegal.

Integration of vertical programs for the control of malaria, schistosomiasis, and soil-transmitted helminthiasis has been recommended to achieve elimination of malaria and neglected tropical diseases (NTD) by 2030. This qualitative study was conducted within the context of a randomized controlled trial to explore the perceptions and views of parents/caregivers of at-risk children and healthcare providers to determine their acceptability of the integrated malaria-helminth treatment approach. Randomly selected parents/caregivers of children enrolled in the trial, healthcare providers, trial staff, malaria, and NTD program managers were interviewed using purpose-designed topic guides. Transcripts obtained from the interviews were coded and common themes identified using content analysis were triangulated. Fifty-seven study participants comprising 26 parents/caregivers, 10 study children aged ≥ 10 years, 15 trial staff, four healthcare providers, and two managers from the Senegal Ministry of Health were interviewed. Thirty-eight of the participants (66.7%) were males, and their ages ranged from 10 to 65 years. Overall, the integrated malaria-helminth treatment approach was considered acceptable, but the study participants expressed concerns about the taste, smell, and side effects associated with amodiaquine and praziquantel in the combination package. Reluctance to accept the medications was also observed among children aged 10 to 14 years due to peer influence and gender-sensitive cultural beliefs. Addressing concerns about the taste and smell of amodiaquine and praziquantel is needed to optimize the uptake of the integrated treatment program. Also, culturally appropriate strategies need to be put in place to cater for the inclusion of children aged 10 to 14 years in this approach.

Therapeutic efficacy of artesunate-amodiaquine and artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Chad: clinical and genetic surveillance.

BACKGROUND: Artesunate-amodiaquine (AS-AQ) and artemether-lumefantrine (AL) are the currently recommended first-and second-line therapies for uncomplicated Plasmodium falciparum infections in Chad. This study assessed the efficacy of these artemisinin-based combinations, proportion of day 3 positive patients, proportions of molecular markers associated with P. falciparum resistance to anti-malarial drugs and variable performance of HRP2-based malaria rapid diagnostic tests (RDTs). METHODS: A single-arm prospective study assessing the efficacy of AS-AQ and AL at three sites (Doba, Kelo and Koyom) was conducted between November 2020 to January 2021. Febrile children aged 6 to 59 months with confirmed uncomplicated P. falciparum infection were enrolled sequentially first to AS-AQ and then AL at each site and followed up for 28 days. The primary endpoint was PCR-adjusted adequate clinical and parasitological response (ACPR). Samples collected on day 0 were analysed for mutations in pfkelch13, pfcrt, pfmdr-1, pfdhfr, pfdhps genes and deletions in pfhrp2/pfhrp3 genes. RESULTS: By the end of 28-day follow-up, per-protocol PCR corrected ACPR of 97.8% (CI 95% 88.2-100) in Kelo and 100% in Doba and Kayoma were observed among AL treated patients. For ASAQ, 100% ACPR was found in all sites. All, but one patient, did not have parasites detected on day 3. Out of the 215 day 0 samples, 96.7% showed pfkelch13 wild type allele. Seven isolates carried nonsynonymous mutations not known to be associated artemisinin partial resistance (ART-R). Most of samples had a pfcrt wild type allele (79% to 89%). The most prevalent pfmdr-1 allele detected was the single mutant 184F (51.2%). For pfdhfr and pfdhps mutations, the quintuple mutant allele N51I/C59R/S108N + G437A/540E responsible for SP treatment failures in adults and children was not detected. Single deletion in the pfhrp2 and pfhrp3 gene were detected in 10/215 (4.7%) and 2/215 (0.9%), respectively. Dual pfhrp2/pfhrp3 deletions, potentially threatening the efficacy of HRP2-based RDTs, were observed in 5/215 (2.3%) isolates. CONCLUSION: The results of this study confirm that AS-AQ and AL treatments are highly efficacious in study areas in Chad. The absence of known pfkelch13 mutations in the study sites and the high parasite clearance rate at day 3 suggest the absence of ART-R. The absence of pfdhfr/pfdhps quintuple or sextuple (quintuple + 581G) mutant supports the continued use of SP for IPTp during pregnancy. The presence of parasites with dual pfhrp2/pfhrp3 deletions, potentially threatening the efficacy of HRP2-based RDTs, warrants the continued surveillance. Trial registration ACTRN12622001476729.

Predictors of caregiver adherence to administration of amodiaquine during delivery of seasonal malaria chemoprevention in Nigeria, Burkina Faso, Chad, and Togo.

BACKGROUND: Malaria is the leading cause of morbidity and mortality among infants and children under-five in sub-Saharan Africa. In the Sahel, seasonal malaria chemoprevention (SMC) is delivered door-to-door in monthly cycles. In each cycle, children are administered sulfadoxine-pyrimethamine (SP) plus amodiaquine (AQ) on Day 1 by community distributors, and AQ on Day 2 and Day 3 by caregivers. Non-adherence to AQ administration by caregivers has implications for emergence of antimalarial resistance. METHODS: Predictors of non-adherence to administration of AQ on Day 2 and Day 3 among caregivers of children aged 3-59 months who had received Day 1 SP and AQ during the last 2020 SMC cycle (n = 12,730) were analysed using data from SMC coverage surveys in Nigeria, Burkina Faso and Togo, and fitting multivariate random-effects logistic regression models. RESULTS: Previous adverse reaction to SMC medicines by eligible children (OR: 0.29, 95% CI 0.24-0.36, p < 0.001), awareness of the importance of administering Day 2 and Day 3 AQ (OR: 2.19, 95% CI 1.69-2.82, p < 0.001), caregiver age, and home visits to caregivers delivered by the Lead Mothers intervention in Nigeria (OR: 2.50, 95% CI 1.93-2.24, p < 0.001), were significantly associated with caregiver adherence to Day 2 and Day 3 AQ administration. CONCLUSIONS: Increasing caregivers' knowledge of SMC and interventions such as Lead Mothers have the potential to improve full adherence to AQ administration.

Plasmodium falciparum kelch13 polymorphisms identified after treatment failure with artemisinin-based combination therapy in Niger.

BACKGROUND: Artemisinin-based combination therapy (ACT) is the most effective treatment for malaria, and has significantly reduced morbimortality. Polymorphisms associated with the Plasmodium falciparum Kelch gene (Pfkelch13) have been associated with delayed parasite clearance even with ACT treatment. METHODS: The Pfkelch13 gene was sequenced from P. falciparum infected patients (n = 159) with uncomplicated malaria in Niger. An adequate clinical and parasitological response (ACPR) was reported in 155 patients. Four (n = 4) patients had treatment failure (TF) that were not reinfections-two of which had late parasitological failures (LPF) and two had late clinical failures (LCF). RESULTS: Thirteen single nucleotide polymorphisms (SNPs) were identified of which seven were non-synonymous (C469R, T508S, R515T, A578S, I465V, I437V, F506L,), and three were synonymous (P443P, P715P, L514L). Three SNP (C469R, F506L, P715P) were present before ACT treatment, while seven mutations (C469R, T508S, R515T, L514L, P443P, I437V, I465V) were selected by artemether/lumefantrine (AL)-five of which were non-synonymous (C469R, T508S, R515T, I437V, I465V). Artesunate/amodiaquine (ASAQ) has selected any mutation. One sample presented three cumulatively non-synonymous SNPs-C469R, T508S, R515T. CONCLUSIONS: This study demonstrates intra-host selection of Pfkelch13 gene by AL. The study highlights the importance of LCF and LPF parasites in the selection of resistance to ACT. Further studies using gene editing are required to confirm the potential implication of resistance to ACT with the most common R515T and T508S mutations. It would also be important to elucidate the role of cumulative mutations.

Seasonal Malaria Chemoprevention Drug Levels and Drug Resistance Markers in Children With or Without Malaria in Burkina Faso: A Case-Control Study.

BACKGROUND: Despite scale-up of seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine (SP-AQ) in children 3-59 months of age in Burkina Faso, malaria incidence remains high, raising concerns regarding SMC effectiveness and selection of drug resistance. Using a case-control design, we determined associations between SMC drug levels, drug resistance markers, and presentation with malaria. METHODS: We enrolled 310 children presenting at health facilities in Bobo-Dioulasso. Cases were SMC-eligible children 6-59 months of age diagnosed with malaria. Two controls were enrolled per case: SMC-eligible children without malaria; and older (5-10 years old), SMC-ineligible children with malaria. We measured SP-AQ drug levels among SMC-eligible children and SP-AQ resistance markers among parasitemic children. Conditional logistic regression was used to compute odds ratios (ORs) comparing drug levels between cases and controls. RESULTS: Compared to SMC-eligible controls, children with malaria were less likely to have any detectable SP or AQ (OR, 0.33 [95% confidence interval, .16-.67]; P = .002) and have lower drug levels (P < .05). Prevalences of mutations mediating high-level SP resistance were rare (0%-1%) and similar between cases and SMC-ineligible controls (P > .05). CONCLUSIONS: Incident malaria among SMC-eligible children was likely due to suboptimal levels of SP-AQ, resulting from missed cycles rather than increased antimalarial resistance to SP-AQ.

Design, Implementation, and Coordination of Malaria Therapeutic Efficacy Studies in Nigeria in 2018.

Prior to 2018, malaria therapeutic efficacy studies (TESs) in Nigeria were implemented separately at different sites, as assigned by the National Malaria Elimination Program (NMEP). In 2018, however, the NMEP engaged the Nigerian Institute of Medical Research to coordinate the 2018 TESs in 3 of 14 sentinel sites with the objective of standardizing their conduct across all three sites: Enugu, Kano, and Plateau states in three of six geopolitical zones. Artemether-lumefantrine and artesunate-amodiaquine, the two first-line drugs for treatment of acute uncomplicated malaria in Nigeria, were tested in both Kano and Plateau states. In Enugu State, however, artemether-lumefantrine and dihydroartemisinin-piperaquine were the test drugs, with dihydroartemisinin-piperaquine being tested for potential inclusion in Nigerian treatment policy. The TES was conducted in 6-month to 8-year-old children and was funded by the Global Fund with additional support from the WHO. A multipartite core team comprised of the NMEP, the WHO, the U.S. Presidential Malaria Initiative, academia, and the Nigerian Institute of Medical Research was set up to oversee the execution of the 2018 TES. This communication reports best practices adopted to guide its coordination, and lessons learned during in the process, including applying developed standard operating procedures, powering the sample size adequately for each site to report independently, training the investigating team for fieldwork, facilitating stratification of decisions, determining efficiencies derived from monitoring and quality assessment, and optimizing logistics. The planning and coordination of the 2018 TES activities is a model of a consultative process for the sustainability of antimalarial resistance surveillance in Nigeria.

A non-randomized controlled trial to assess the protective effect of SMC in the context of high parasite resistance in Uganda.

BACKGROUND: Until recently, due to widespread prevalence of molecular markers associated with sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ) resistance in east and southern Africa, seasonal malaria chemoprevention (SMC) has not been used at scale in this region. This study assessed the protective effectiveness of monthly administration of SP + AQ (SPAQ) to children aged 3-59 months in Karamoja sub-region, Uganda, where parasite resistance is assumed to be high and malaria transmission is seasonal. METHODS: A two-arm quasi-experimental, open-label prospective non-randomized control trial (nRCT) was conducted in three districts. In two intervention districts, 85,000 children aged 3-59 months were targeted to receive monthly courses of SMC using SPAQ during the peak transmission season (May to September) 2021. A third district served as a control, where SMC was not implemented. Communities with comparable malaria attack rates were selected from the three districts, and households with at least one SMC-eligible child were purposively selected. A total cohort of 600 children (200 children per district) were selected and followed using passive surveillance for breakthrough confirmed malaria episodes during the five-month peak transmission season. Malaria incidence rate per person-months and number of malaria episodes among children in the two arms were compared. Kaplan-Meier failure estimates were used to compare the probability of a positive malaria test. Other factors that may influence malaria transmission and infection among children in the two arms were also assessed using multivariable cox proportional hazards regression model. RESULTS: The malaria incidence rate was 3.0 and 38.8 per 100 person-months in the intervention and control groups, respectively. In the intervention areas 90.0% (361/400) of children did not experience any malaria episodes during the study period, compared to 15% (29/200) in the control area. The incidence rate ratio was 0.078 (95% CI 0.063-0.096), which corresponds to a protective effectiveness of 92% (95% CI 90.0-94.0) among children in the intervention area. CONCLUSION: SMC using SPAQ provided high protective effect against malaria during the peak transmission season in children aged 3-59 months in the Karamoja sub-region of Uganda.

Optimization of HPLC-MS/MS method for determination of antimalarial adulterants in herbal products.

The use of herbal products is booming all over the world because of being believed as safer than conventional drugs and free of side effects. However, there are untrustworthy manufacturers who adulterate herbal products by adding conventional drugs which might eventually lead to microbial resistance and herb-to-drug interactions. There is a need to develop methods for detecting adulterants in herbal products. A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for simultaneous identification and determination of conventional antimalarials (chloroquine, quinine, sulfadoxine, pyrimethamine, mefloquine, lumefantrine, amodiaquine, artemisinin, dihydroartemisinin, artesunate and artemether) in herbal products was developed. Stable isotopically labelled compounds (artemether-d3, quindine-d3, and sulfadoxine-d3) were used as internal standards (ISs) for quantitative analysis. Extraction of analytes was performed using methanol: water: formic acid (90:10:0.1, v/v) and chromatographic separation was done in a gradient mode using mobile phase A: Ultrapure water containing 0.1% formic acid and 1 mM ammonium formate and mobile phase B: Acetonitrile/methanol (50:50) containing 0.1% formic acid and 1 mM ammonium formate. The calibration curves were linear (r2 ≥ 0.991) over the range of 0.001-0.3 µg mL-1 for all compounds. The limit of detection (LOD) ranged from 0.002 to 0.02 µg mL-1 while the limit of quantification (LOQ) ranged from 0.006 to 0.08 µg mL-1. Accuracy, expressed as recovery of spiked herbal products ranged from 52 to 128%. The precision, expressed as percent relative standard deviation (%RSD) at two concentration levels, ranged from 1.0 to 13.8%. The matrix effect expressed as the matrix factor (MF) ranged from 0.77 to 0.97. The developed method was used to identify and quantify conventional antimalarials in herbal product samples from Tanzania. Ten out of 50 herbal products were found to contain amodiaquine, sulfadoxine, pyrimethamine, mefloquine, dihydroartemisinin, artemether and lumefantrine. The developed method is considered a valuable tool for getting a better understanding of the adulteration of conventional antimalarials in herbal products.

Exploring the repositioning of the amodiaquine as potential drug against visceral leishmaniasis: The in vitro effect against Leishmania infantum is associated with multiple mechanisms, involving mitochondria dysfunction, oxidative stress and loss of cell cycle control.

Visceral leishmaniasis (VL) is a progressive, debilitating, and potentially fatal disease if left untreated. As a neglected tropical disease (NTD), the available treatment is restricted to a few drugs, which typically must be administered over a long period but are associated with serious adverse effects and have variability in efficacy. In this sense, drug repositioning has been considered an excellent strategy in the search for alternative treatments, especially in reducing the time and cost of the research. In this work, the repositioning potential of amodiaquine (AQ), a well-known antimalarial drug, was investigated for the treatment of VL. AQ showed significant and selective activity against promastigotes (IC50 = 11.6 µg/mL) and intracellular amastigotes (IC50 = 2.4 µg/mL) of L. infantum, being 10 times more destructive to the intracellular parasites than the host cell. In addition, pre-treatment of macrophages with AQ caused a significant reduction in the infection index, indicating a prophylactic effect of this drug. SEM images showed that AQ induces strong shape alterations of the promastigotes with an increase in cell volume with rounding and ribbing (vertical ridges), as well as a shortened flagellum. In addition, AQ induced depolarization of the ΔΨm, an increase in ROS and neutral lipids levels, and changes in the cell cycle in promastigotes, without alterations to the permeability of the parasite plasma membrane. L. infantum-infected macrophages treated with AQ induced the activation of oxidative mechanisms by infected host cells, with an increase in ROS and NO levels. Finally, in vitro interactions between AQ and miltefosine were found to have an additive effect in both biological stages of the parasite, with the ∑FIC50 values ranging from 0.74 to 1.16 µg/mL and 0.54-1.11 µg/mL for promastigotes and intracellular amastigotes, respectively. Overall, these data highlight the utility of drug repurposing and indicate future preclinical testing for AQ itself or in combination as a potential VL treatment.

Prevalence of Plasmodium falciparum haplotypes associated with resistance to sulfadoxine-pyrimethamine and amodiaquine before and after upscaling of seasonal malaria chemoprevention in seven African countries: a genomic surveillance study.

BACKGROUND: Seasonal malaria chemoprevention is used in 13 countries in the Sahel region of Africa to prevent malaria in children younger than 5 years. Resistance of Plasmodium falciparum to seasonal malaria chemoprevention drugs across the region is a potential threat to this intervention. METHODS: Between December, 2015, and March, 2016, and between December, 2017, and March, 2018, immediately following the 2015 and 2017 malaria transmission seasons, community surveys were done among children younger than 5 years and individuals aged 10-30 years in districts implementing seasonal malaria chemoprevention with sulfadoxine-pyrimethamine and amodiaquine in Burkina Faso, Chad, Guinea, Mali, Nigeria, Niger and The Gambia. Dried blood samples were collected and tested for P falciparum DNA by PCR. Resistance-associated haplotypes of the P falciparum genes crt, mdr1, dhfr, and dhps were identified by quantitative PCR and sequencing of isolates from the collected samples, and survey-weighted prevalence and prevalence ratio between the first and second surveys were estimated for each variant. FINDINGS: 5130 (17·5%) of 29 274 samples from 2016 and 2176 (7·6%) of 28 546 samples from 2018 were positive for P falciparum on quantitative PCR. Among children younger than 5 years, parasite carriage decreased from 2844 of 14 345 samples (19·8% [95% CI 19·2-20·5]) in 2016 to 801 of 14 019 samples (5·7% [5·3-6·1]) in 2018 (prevalence ratio 0·27 [95% CI 0·24-0·31], p<0·0001). Genotyping found no consistent evidence of increasing prevalence of amodiaquine resistance-associated variants of crt and mdr1 between 2016 and 2018. The dhfr haplotype IRN (consisting of 51Ile-59Arg-108Asn) was common at both survey timepoints, but the dhps haplotype ISGEAA (431Ile-436Ser-437Gly-540Glu-581Ala-613Ala), crucial for resistance to sulfadoxine-pyrimethamine, was always rare. Parasites carrying amodiaquine resistance-associated variants of both crt and mdr1 together with dhfr IRN and dhps ISGEAA occurred in 0·05% of isolates. The emerging dhps haplotype VAGKGS (431Val-436Ala-437Gly-540Lys-581Gly-613Ser) was present in four countries. INTERPRETATION: In seven African countries, evidence of a significant reduction in parasite carriage among children receiving seasonal malaria chemoprevention was found 2 years after intervention scale-up. Combined resistance-associated haplotypes remained rare, and seasonal malaria chemoprevention with sulfadoxine-pyrimethamine and amodiaquine is expected to retain effectiveness. The threat of future erosion of effectiveness due to dhps variant haplotypes requires further monitoring. FUNDING: Unitaid.

Surveillance des effets indésirables lors des campagnes de la chimioprévention du paludisme saisonnier chez les enfants de 3-59 mois au Burkina Faso.

INTRODUCTION: Seasonal malaria chemoprevention (SMC) by mass administration of sulfadoxine pyrimethamine + amodiaquine (SPAQ) reduces the burden of malaria in children aged 3-59 months. The occurrence of adverse drug reaction (ADR) may affect the success of this intervention. There are few studies of SMC adverse event surveillance in sub-Saharan Africa, particularly in Burkina Faso, a highly endemic country. Our main objective was to characterize the ADRs reported during SMC campaigns in Burkina Faso. Secondly, we evaluated the performance of the pharmacovigilance integrated into the SMC program in order to support safe administration of SMC. METHOD: This was a retrospective descriptive study of SMC individual case safety reports recorded in VigiBase® in Burkina Faso from 2014 to 2021. We used the P-method for the analysis of preventable serious adverse drug reactions and WHO criteria for assessing the performance of pharmacovigilance integrated into the SMC program. RESULTS: A total of 1,105 SMC individual case safety reports were registered in VigiBase® for 23,311,453 doses of SPAQ given between 2014 and 2021. No pharmacovigilance signal was detected. The number of serious cases was 101, of which 23 (22.8%) were preventable. In 38.1% of children, the occurrence of ADRs led to discontinuation of SMC treatment. Vomiting was the most frequently reported adverse drug reaction (48.0%). The proportion of children whose treatment was discontinued due to vomiting was 42.7%, while the proportion of treatment discontinuation for other ADRs was 32.8% (p = 0.01). The SMC program contributed at 46.2% to the national pharmacovigilance database. The reporting rate was 0.03 per 1,000 exposed children in 2021. The median completeness score of the ICSRs was 0.7 (IQR: 0.5-0.7), and the median time to register the ICSRs in VigiBase® was 204 (IQR: 143-333) days. CONCLUSIONS: Post-drug administration vomiting may interfere with the purpose of SMC. Measures to manage this adverse drug reaction should be taken to improve the success of the SMC program. Based on the information on reporting time and reporting rate, spontaneous reporting should be supported by active surveillance, including cohort event monitoring, in Burkina Faso.

A hybrid effectiveness-implementation study protocol to assess the effectiveness and chemoprevention efficacy of implementing seasonal malaria chemoprevention in five districts in Karamoja region, Uganda.

Background: The World Health Organization (WHO) recommends seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine (SPAQ) for children aged 3 to 59 months, living in areas where malaria transmission is highly seasonal. However, due to widespread prevalence of resistance markers, SMC has not been implemented at scale in East and Southern Africa. An initial study in Uganda showed that SMC with SPAQ was feasible, acceptable, and protective against malaria in eligible children in Karamoja region. Nonetheless, exploration of alternative regimens is warranted since parasite resistance threats persist. Objective: The study aims to test the effectiveness of SMC with Dihydroartemisinin-piperaquine (DP) or SPAQ (DP-SMC & SPAQ-SMC), chemoprevention efficacy as well as the safety and tolerability of DP compared to that of SPAQ among 3-59 months old children in Karamoja region, an area of Uganda where malaria transmission is highly seasonal. Methods: A Type II hybrid effectiveness-implementation study design consisting of four components: 1) a cluster randomized controlled trial (cRCT) using passive surveillance to establish confirmed malaria cases in children using both SPAQ and DP; 2a) a prospective cohort study to determine the chemoprevention efficacy of SPAQ and DP (if SPAQ or DP clears sub-patent infection and provides 28 days of protection from new infection) and whether drug concentrations and/or resistance influence the ability to clear and prevent infection; 2b) a sub study examining pharmacokinetics of DP in children between 3 to <6 months; 3) a resistance markers study in children 3-59 months in the research districts plus the standard intervention districts to measure changes in resistance marker prevalence over time and finally; 4) a process evaluation. Discussion: This study evaluates the effects of SPAQ-SMC versus DP-SMC on clinical malaria in vulnerable children in the context of high parasite SP resistance, whilst informing on the best implementation strategies. Conclusion: This study will inform malaria policy in high-burden countries, specifically on utility of SMC outside the sahel, and contribute to progress in malaria control.

Comparative effect of artemether-lumefantrine and artesunate-amodiaquine on gametocyte clearance in children with uncomplicated Plasmodium falciparum malaria in Madagascar.

BACKGROUND: Gametocytes are the sexual stages ensuring continuity of the development cycle of the parasite, as well as its transmission to humans. The efficacy of artemisinin-based anti-malarials against asexual stages of Plasmodium has been reported in Madagascar, but their effects on gametocytes are not well documented. The present study aims to determine the emergence of gametocyte and gametocyte clearance after artesunate-amodiaquine (ASAQ) or artemether-lumefantrine (AL) treatment in children with uncomplicated Plasmodium falciparum malaria in 5 regions of Madagascar. METHODS: 558 children with uncomplicated P. falciparum malaria, aged between 1 and 15 years, were assigned randomly to AL or ASAQ treatment. They come from 5 regions of Madagascar with different epidemiological facies related to malaria: Ankilivalo, Benenitra, Ampanihy, Ankazomborona and Matanga. Gametocytes were identified by microscopy, from t blood smears at day 1, day 2, day 3, day 7, day 14, day 21 and day 28 after treatment. RESULTS: At baseline, 9.7% (54/558) children [95% CI: 7.4-12.5%] had detectable gametocyte by microscopy. Among the 54 enrolled children, gametocytes emergence rate was high during the first days of treatment in both treatment arms (AL and ASAQ), especially on day 1. Gametocytes were undetectable from day 14 for AL arm while for ASAQ arm, gametocyte carriage was gradually decreased but persisted until day 21. CONCLUSION: This study demonstrates that AL has a more rapid effect on gametocyte clearance compared to ASAQ in children with uncomplicated Plasmodium falciparum malaria.

A Decade of Progress Accelerating Malaria Control in Mali: Evidence from the West Africa International Center of Excellence for Malaria Research.

This article highlights over a decade of signature achievements by the West Africa International Centers for Excellence in Malaria Research (WA-ICEMR) and its partners toward guiding malaria prevention and control strategies. Since 2010, the WA-ICEMR has performed longitudinal studies to monitor and assess malaria control interventions with respect to space-time patterns, vector transmission indicators, and drug resistance markers. These activities were facilitated and supported by the Mali National Malaria Control Program. Research activities included large-scale active and passive surveillance and expanded coverage of universal long-lasting insecticide-treated bed nets and seasonal malaria chemoprevention (SMC). The findings revealed substantial declines in malaria occurrence after the scale-up of control interventions in WA-ICEMR study sites. WA-ICEMR studies showed that SMC using sulfadoxine-pyrimethamine plus amodiaquine was highly effective in preventing malaria among children under 5 years of age. An alternative SMC regimen (dihydroartemisinin plus piperaquine) was shown to be potentially more effective and provided advantages for acceptability and compliance over the standard SMC regimen. Other findings discussed in this article include higher observed multiplicity of infection rates for malaria in historically high-endemic areas, continued antimalarial drug sensitivity to Plasmodium falciparum, high outdoor malaria transmission rates, and increased insecticide resistance over the past decade. The progress achieved by the WA-ICEMR and its partners highlights the critical need for maintaining current malaria control interventions while developing novel strategies to disrupt malaria transmission. Enhanced evaluation of these strategies through research partnerships is particularly needed in the wake of reported artemisinin resistance in Southeast Asia and East Africa.