Parasitological Failure Research Articles

Assessing the therapeutic efficacy of artemether-lumefantrine for uncomplicated malaria in Lagos, Nigeria: a comprehensive study on treatment response and resistance markers

BackgroundThe burden of malaria persists in sub-Saharan Africa and the emergence of artemisinin resistance has introduced complexity to control efforts. Monitoring the efficacy of artemisinin-based treatment for malaria is crucial to address this challenge. This study assessed treatment efficacy of artemether-lumefantrine (AL) and genetic diversity of Plasmodium falciparum isolates in a Nigerian population.MethodsParticipants presenting with clinical symptoms of uncomplicated malaria at a health centre in Lagos, Nigeria, were screened for P. falciparum. Enrolled participants were treated with AL and monitored through scheduled check-up visits, clinical and laboratory examinations for 28 days. Parasite clearance and genetic diversity were assessed through polymerase chain reaction (PCR) analysis of merozoite surface proteins (msp1 and msp2). The prevalence of drug resistance mutations was assessed by P. falciparum multidrug resistance gene 1 (mdr1) genotyping followed by P. falciparum ubiquitin-specific protease 1 (ubp1) gene sequencing.ResultsThe PCR-uncorrected treatment outcome revealed 94.4% adequate clinical and parasitological response (ACPR) and 5.6% late parasitological failure (LPF) rates. After PCR correction, no suspected LPF case was detected and ACPR 67/67 (100%) was achieved in all the individuals. Moreover, a high prevalence of wild-type alleles for mdr1 N86Y (93.7%), and mdr1 D1246Y (87.5%) was observed. Genetic diversity analysis revealed predominant K1 allelic family for msp1 (90.2%) and FC27 for msp2 (64.4%). Estimated multiplicity of infection (MOI) was 1.7, with the highest MOI observed in the 5–15 years age group. ubp1 sequence analysis identified one nonsynonymous E1528D polymorphism at a low frequency (1.6%).ConclusionThe study demonstrated sustained efficacy of AL for treating uncomplicated P. falciparum malaria. Genetic diversity analysis revealed various allelic types, suggesting occurrences of polyclonal infections. Nonetheless, the detection of a significant ubp1 polymorphism could have future implications for the epidemiology of anti-malarial drug resistance in the population.

Chloroquine has shown high therapeutic efficacy against uncomplicated Plasmodium vivax malaria in southern Ethiopia: seven decades after its introduction

BackgroundPlasmodium vivax malaria is a leading cause of morbidity in Ethiopia. The first-line treatment for P. vivax is chloroquine (CQ) and primaquine (PQ), but there have been local reports of CQ resistance. A clinical study was conducted to determine the efficacy of CQ for the treatment of P. vivax malaria in southern Ethiopia.MethodsIn 2021, patients with P. vivax mono-infection and uncomplicated malaria were enrolled and treated with 25 mg/kg CQ for 3 consecutive days. Patients were followed for 28 days according to WHO guidelines. The data were analysed using per-protocol (PP) and Kaplan‒Meier (K‒M) analyses to estimate the risk of recurrent P. vivax parasitaemia on day 28.ResultsA total of 88 patients were enrolled, 78 (88.6%) of whom completed the 28 days of follow-up. Overall, 76 (97.4%) patients had adequate clinical and parasitological responses, and two patients had late parasitological failures. The initial therapeutic response was rapid, with 100% clearance of asexual parasitaemia within 48 h.ConclusionDespite previous reports of declining chloroquine efficacy against P. vivax, CQ retains high therapeutic efficacy in southern Ethiopia, supporting the current national treatment guidelines. Ongoing clinical monitoring of CQ efficacy supported by advanced molecular methods is warranted to inform national surveillance and ensure optimal treatment guidelines.

Detection of novel Plasmodium falciparum coronin gene mutations in a recrudescent ACT-treated patient in South-Western Nigeria.

Routine surveillance for antimalarial drug resistance is critical to sustaining the efficacy of artemisinin-based Combination Therapies (ACTs). Plasmodium falciparum kelch-13 (Pfkelch-13) and non-Pfkelch-13 artemisinin (ART) resistance-associated mutations are uncommon in Africa. We investigated polymorphisms in Plasmodium falciparum actin-binding protein (Pfcoronin) associated with in vivo reduced sensitivity to ART in Nigeria. Fifty-two P. falciparum malaria subjects who met the inclusion criteria were followed up in a 28-day therapeutic efficacy study of artemether-lumefantrine in Lagos, Nigeria. Parasite detection was done by microscopy and molecular diagnostic approaches involving PCR amplification of genes for Pf18S rRNA, varATS, telomere-associated repetitive elements-2 (TARE-2). Pfcoronin and Pfkelch-13 genes were sequenced bi-directionally while clonality of infections was determined using 12 neutral P. falciparum microsatellite loci and msp2 analyses. Antimalarial drugs (sulfadoxine-pyrimethamine, amodiaquine, chloroquine and some quinolones) resistance variants (DHFR_51, DHFR_59, DHFR_108, DHFR_164, MDR1_86, MDR1_184, DHPS_581 and DHPS_613) were genotyped by high-resolution melting (HRM) analysis. A total of 7 (26.92%) cases were identified either as early treatment failure, late parasitological failure or late clinical failure. Of the four post-treatment infections identified as recrudescence by msp2 genotypes, only one was classified as recrudescence by multilocus microsatellites genotyping. Microsatellite analysis revealed no significant difference in the mean allelic diversity, He, (P = 0.19, Mann-Whitney test). Allele sizes and frequency per locus implicated one isolate. Genetic analysis of this isolate identified two new Pfcoronin SNVs (I68G and L173F) in addition to the P76S earlier reported. Linkage-Disequilibrium as a standardized association index, IAS, between multiple P. falciparum loci revealed significant LD (IAS = 0.2865, P=0.02, Monte-Carlo simulation) around the neutral microsatellite loci. The pfdhfr/pfdhps/pfmdr1 drug resistance-associated haplotypes combinations, (108T/N/51I/164L/59R/581G/86Y/184F), were observed in two samples. Pfcoronin mutations identified in this study, with potential to impact parasite clearance, may guide investigations on emerging ART tolerance in Nigeria, and West African endemic countries.

Genetic Evaluation of Interlukin-22 Single Nucleotide Polymorphism (rs1179251) with Plasmodium falciparum Clearance among Children Less Than 10 Years in the North Region of Cameroon

IL-22 is a pro and anti-inflammatory cytokine which induces the regeneration of hepatocytes cells during the immune response. Evidence has shown that genetic polymorphisms on IL-22 gene could affect the immune response and consequently the parasite clearance and the treatment outcome of malaria. This study aimed at determining the prevalence of the SNP rs1179251 of the Interleukin-22 gene and a possible association with P. falciparum clearance among children less than 10 years old in the North region of Cameroon. A case-control study was performed on 184 conveniently collected blood samples, spotted on Whartman No 3 filter paper from the SPAQ (Sulfadoxine-Pyrimethamine + Amodiaquine) clinical trial carried out in Garoua and Yagoua in 2015, from which DNA was extracted using Chelex-100 method. Genotyping of the IL-22 gene SNPs was performed using Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP). Parasite clearance was defined as the disappearance of pre-treatment parasites without subsequent recurrence, irrespective of whether recurrence is a reinfection or a recrudescing parasite. Treatment outcomes were classified according to the WHO guidelines; patients that experienced early treatment failure (ETF), and late parasitological failure (LPF) were classified as failures (56 cases), while patients that experienced adequate clinical parasitological response (ACPR) were classified as successes (128 controls). The chi square test was used to establish the association between the SNP rs1179251 and parasite clearance. A P-value less than 0.05 was considered as statistically significant. The findings revealed that the mutant allele C was the most predominant with a frequency of 74.46%, with the ancestral allele G having a frequency of 25.54%. These results showed that carriers of the mutant allele C could be 3.7 times more likely not to clear the parasites during treatment but this was not statistically significant (P=0.07, OR= 3.72). In conclusion, no association was found between the SNP rs1179251 of IL-22 gene and Plasmodium falciparum clearance. So, in spite of the importance of IL-22 gene in immune responses, the studied polymorphism does not serve a decisive role in Plasmodium falciparum clearance.

Evolution of genetic markers for drug resistance after the introduction of dihydroartemisinin–piperaquine as first-line anti-malarial treatment for uncomplicated falciparum malaria in Indonesia

BackgroundDihydroartemisinin–piperaquine has been Indonesia’s first-line anti-malarial treatment since 2008. Annual therapeutic efficacy studies (TES) done in the last 12 years showed continued high treatment efficacy in uncomplicated Plasmodium falciparum malaria. Although these studies did not show evidence for artemisinin resistance, a slight increase in Late Treatment Failure was observed over time. It is highlight to explore the evolution of genetic markers for ACT partner drug resistance since adopting DHA–PPQ.MethodsDry blood spots were identified from a mass blood survey of uncomplicated falciparum malaria patients (N = 50) in Sumba from 2010 to 2018. Analysis of genotypic profile (N = 51) and a Therapeutic Efficacy Study (TES) from Papua (N = 142) from 2020 to 2021, 42-day follow-up. PCR correction using msp1, msp2, and glurp was used to distinguish recrudescence and reinfection. Parasite DNA from DBSs was used for genotyping molecular markers for antimalaria drug resistance, including in Pfk13, pfcrt, and pfmdr1, as well as gene copy number variation in pfpm2/3 and pfmdr1.ResultsThe study revealed the absence of SNPs associated with ART resistance and several novel SNPs such as L396F, I526V, M579I and N537S (4.25%). In Sumba, the mutant haplotype SDD of pfmdr1 was found in one-third of the isolates, while only 8.9% in Papua. None of the pfcrt mutations linked to piperaquine resistance were observed, but 71% of isolates had pfcrt I356L. Amplification of the pfpm2/3 genes was in Sumba (17.02%) and Papua (13.7%), while pfmdr1 copy number prevalence was low (3.8%) in both areas. For the TES study, ten recurrences of infection were observed on days 28, 35, and 42. Late parasitological failure (LPF) was observed in 10/117 (8.5%) subjects by microscopy. PCR correction revealed that all nine cases were re-infections and one was confirmed as recrudescence.ConclusionThis study revealed that DHA–PPQ is still highly effective against P. falciparum. The genetic architecture of the parasite P. falciparum isolates during 2010–2021 revealed single copy of Pfpm2 and pfmdr1 were highly prevalent. The slight increase in DHA–PPQ LTF alerts researchers to start testing other ACTs as alternatives to DHA–PPQ for baseline data in order to get a chance of achieving malaria elimination wants by 2030.Graphical

A case of complicated falciparum malaria from coming back from Myanmar-India border presenting with cerebral malaria, black water fever, acute kidney injury, metabolic acidosis, hypocalcemia, severe anemia, thrombocytopenia and hepatitis having early parasitological failure on Day 14: Awareness on dihydroartemisinine-piperaquine combination therapy

A-39-year-old migrant worker coming back from Palatwa (Sagaing Division) and Myanmar-India border area (Rakhine State) developed cerebral malaria

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

BackgroundArtemisinin-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.MethodsThe 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).ResultsThirteen 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.ConclusionsThis 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.

Treatment of uncomplicated Plasmodium vivax with chloroquine plus radical cure with primaquine without G6PDd testing is safe in Arba Minch, Ethiopia: assessment of clinical and parasitological response

BackgroundEthiopia rolled out primaquine nationwide in 2018 for radical cure along with chloroquine for the treatment of uncomplicated Plasmodium vivax malaria in its bid for malaria elimination by 2030. The emergence of anti-malarial drug resistance would challenge the elimination goal. There is limited evidence on the emergence of chloroquine drug resistance. The clinical and parasitological outcomes of treatment of P. vivax with chloroquine plus radical cure using low dose 14 days primaquine were assessed in an endemic area of Ethiopia.MethodsA semi-directly observed 42-days follow up in-vivo therapeutic efficacy study was conducted from October 2019 to February 2020. Plasmodium vivax mono-species infected patients (n = 102) treated with a 14 days low dose (0.25 mg/kg body weight per day) primaquine plus chloroquine (a total dose of 25 mg base/kg for 3 days) were followed for 42 days to examine clinical and parasitological outcomes. Samples collected at recruitment and days of recurrence were examined by 18 S based nested polymerase chain reaction (nPCR) and Pvmsp3α nPCR-restriction fragment length polymorphism. Asexual parasitaemia and the presence of gametocytes were assessed on the scheduled days using microscopy. Clinical symptoms, haemoglobin levels, and Hillmen urine test were also assessed.ResultsOf the 102 patients followed in this study, no early clinical and parasitological failure was observed. All patients had adequate clinical and parasitological responses within the 28 days of follow up. Late clinical (n = 3) and parasitological (n = 6) failures were observed only after day 28. The cumulative incidence of failure was 10.9% (95% confidence interval, 5.8–19.9%) on day 42. Among the paired recurrent samples, identical clones were detected only in two samples on day 0 and day of recurrences (day 30 and 42) using Pvmsp3α genotyping. No adverse effect was detected related to the low dose 14 days primaquine administrations.ConclusionCo-administration of CQ with PQ in the study area is well tolerated and there was no recurrence of P. vivax before 28 days of follow up. Interpretation of CQ plus PQ efficacy should be done with caution especially when the recurrent parasitaemia occurs after day 28. Therapeutic efficacy studies with appropriate design might be informative to rule out chloroquine or primaquine drug resistance and/or metabolism in the study area.

SERIOUS ANTIMALARIA RESISTANCE, GENETIC MARKERS OF KELCH 13, PLASMEPSINE 2 CNV ASSOCIATED WITH DIHYDROARTEMISININE - PIPERAQUINE RESISTANCE IN Plasmodium falciparum POPULATION IN MALARIA ENDEMIC ZONE OF DAKLAK PROVINCE, 2019 - 2020

Backgrounds: Dihydroartemisinin - piperaquine is a current frontline drug recommended in global by WHO for the treatment of Plasmodium falciparum malaria (WHO, 2015), but is now failing in Vietnam provinces where border Cambodia, and has emerged and spread. The purpose of this study was to evaluate efficacy and molecular markers of dihydroartemisinin - piperaquine failures in Daklak province. 
 Methods: A study design of non - randomized controlled study design for the 42 day - course follow - up in vivo test, and the molecular markers analysis. 
 Findings: The data showed that adequate clinical and parasitological response was sharply declined of 12,1%, late clinical failure of 51.5%, late parasitological failure of 36.4%, proportion of positive parasitemia at D3 is 37%, slope half - life of 5.36 hrs, and progressive parasite clearance PC50, PC75, PC 90, PC95, and PC99 were 13.24; 19.29; 25.69; 29.97 and 39.15 hrs, respectively. Molecular markers of C580Y Kelch mutation observed 100% (50/50) in the patients, increased of Plasmepsine 2 CNV of 72% (36/50), and both K13 and Plasmepsine 2 of 72% (36/50). 
 Conclusions: The DHA - PPQ efficacy severely decreased of 12.1%, overall treatment failure of 87.9% with the prominent C580Y mutant plus increased Plasmepsine 2 copy number variation in delayed asexual P. falciparum parasite clearance. These obvious data need to urgently change antimalarial policy in DHA - PPQ resistance zones.

Revealing the artemisinin and piperaquine treatment failure: a systematic review

Background: Artemisinin-based combination therapy (ACT) consists of a potent artemisinin component. Since the dihydroartemisinin performance effectiveness depends on piperaquine interaction still challenging, further research needs to establish the current status of artemisinin resistance relative to its geography and recognize any drug resistance interaction between dihydroartemisinin and piperaquine. Aim: This systematic review was aimed to find out the effect of dihydroartemisinin and piperaquine interaction concerning resistance, recurrence, parasitological failure, clinical failure, parasite clearance time, parasite reduction ratio, cure rate, which may affect treatment failure of patients with uncomplicated P. falciparum. Method: The article was not limited to year and country. This study analyzed any effect of interaction. Pubmed and Scopus were used as electronic databases, and MeSH terms and keywords were used to find specific studies. A total of 2131 studies were initially identified; however, 20 were eligible for qualitative synthesis. Result: The dihydroartemisinin piperaquine cure rate reported in Asia and Africa was above 98%. Eight RCTs, eleven prospective cohort studies, and one retrospective and prospective cohort study were included in this review. Design studies did not compare the same anti-malarial drug pattern, so it was difficult to do a pooled analysis. Even though this drug combination did not show a clear description of piperaquine resistance can affect artemisinin resistance, the adequate clinical and parasitological failure (ACPR) from this research reached above 93%, and for early treatment failure (ETF), late clinical failure (LCF), and late parasitological failure (LPF), were almost 0 %. Conclusion: The dihydroartemisinin-piperaquine combination still has highly efficacious therapy to fight malaria in some areas based on these multiple factors and reviews.

Safety and therapeutic efficacy of artemether-lumefantrine in the treatment of uncomplicated Plasmodium falciparum malaria at Shecha health centre, Arba Minch, Ethiopia

BackgroundIn 2004, Ethiopia adopted artemether-lumefantrine (AL, Coartem®) as first-line treatment for the management of uncomplicated Plasmodium falciparum malaria. Continuous monitoring of AL therapeutic efficacy is crucial in Ethiopia, as per the World Health Organization (WHO) recommendation. This study aimed to assess the therapeutic efficacy of AL in the treatment of uncomplicated P. falciparum infection.MethodsA 28 day onearm, prospective evaluation of the clinical and parasitological response to AL was conducted at Shecha Health Centre, Arba Minch town, Southern Ethiopia. Patients were treated with six-dose regimen of AL over three days and monitored for 28 days with clinical and laboratory assessments. Participant recruitment and outcome classification was done in accordance with the 2009 WHO methods for surveillance of anti-malarial drug efficacy guidelines.ResultsA total of 88 study participants were enrolled and 69 of them completed the study with adequate clinical and parasitological response. Two late parasitological failures were observed, of which one was classified as a recrudescence by polymerase chain reaction (PCR). The PCRcorrected cure rate was 98.6% (95% CI 92.3–100). AL demonstrated a rapid parasite and fever clearance with no parasitaemia on day 2 and febrile cases on day 3. Gametocyte clearance was complete by day three. No serious adverse events were reported during the 28 days follow-up.ConclusionThe study demonstrated high therapeutic efficacy and good safety profile of AL. This suggests the continuation of AL as the first-line drug for the treatment of uncomplicated P. falciparum malaria in Ethiopia. Periodic therapeutic efficacy studies and monitoring of markers of resistance are recommended for early detection of resistant parasites.

Plasmodium vivax Relapse Rates in Allied Soldiers during the Second World War: Importance of Hypnozoite Burden.

Allied soldiers suffered repeated relapses of Plasmodium vivax malaria during and immediately after the Second World War. This surprised many military medical officers who had underestimated the huge casualties produced by P. vivax malaria. Tropical (Philippines) strains of P. vivax were known to relapse more frequently than those from temperate regions (the United States). Intense exposure to mosquito infection likely increased the absolute number of hypnozoites in soldiers' livers. Both quinine and quinacrine were used as chemosuppressive agents, but their inconsistent use until at least 1943 promoted intermittent parasitological failures. Fear of hemolytic reactions after a mass casualty event in 1943 engendered fear and avoidance of the only 8-aminoquinoline pamaquine then available to cure relapses. Variable chemosuppression likely prevented acquisition of effective parasitological immunity. Unexpectedly high relapse rates in soldiers were likely an indirect measure of the high hypnozoite burden and suggest how difficult it will be to eliminate P. vivax malaria from endemic areas.

Influence of Vector Control and Chemotherapy Interventions on Treatment Outcomes and Parasite Incidence in Artemether Combined Therapies Treated Populations of Kisii County, Kenya

Introduction: Malaria remains the major vector borne disease in the world. Currently Kenya the ministry of health has scaled up interventions with chemotherapy and vector control standing out as a major strategy. Therefore, this study examined the influence of vector control and chemotherapy interventions on the treatment outcomes in Kisii County.
 Methods: Multi-stage random sampling was used for this study. The study was conducted from February 2021 to June 2021. Malaria-positive 275 participants were recruited into the study, treated with ACTs and followed for a period of 28 days at specified follow up days for parasite diagnosis. Occurrence of malaria clinical symptoms on the patients was also conducted. Molecular analysis was done by characterizing Merozoite proteins (MSP2) on the samples showing parasite recurrence. A Questionnaire was administered to determine the utilization of drugs for malaria treatment prior to this study and the usage of vector control after patient treatment with ACTs. Meanwhile, emphasis was laid on intervention strategies such as the use the usage of insecticide-treated nets (ITNs), Indoor residual spraying and chemotherapeutic practices as recommended by the World Health Organization (WHO).
 Results: Early treatment failure was reported among 27(12%) respondents, late clinical failures 20(8%), late parasitological failures 11(5%), and adequate clinical and parasitological outcomes 173(75%).Chemotherapeutic practices influencing treatment outcomes included; previous self-medication (OR=0.417; 95% CI: 0.153-1.385; p=0.035), ability of previously finishing doses (OR=0.328; 95% CI: 0.168-0.941; p=0.003,) and Frequency of previous antimalarial usage (OR=3.259; 95% CI: 1.054-4.721; p=0.004). While vector control interventions influencing treatment outcomes included; usage of indoor residual spraying (OR=0.408; 95% CI: 0.132-0.682; p=0.002), sleeping under the mosquito net (OR=0.218; 95% CI: 0.119-0.909; p=0.025,) and mosquito net treatment (OR=0.262; 95% CI: 0.092-0.823; p=0.003).With the molecular analysis detecting 10 samples with parasite recrudescence.
 Conclusions: Based on these findings, Antimalarial usage practices prior to current usage of ACTs and vector control after treatment remain important predictor factors for treatment outcomes.

Effect of Nevirapine-based Antiretroviral Therapy on the Treatment Outcome of Uncomplicated Malaria with Artemether-Lumefantrine among HIV-infected children

Background: The geographical overlap of malaria and HIV in sub-Saharan Africa posed a major public health challenge, which is further worsened by the potential interactions between antimalarial and antiretroviral drugs when co-administered. This study aimed to compare the responses to artemether/lumefantrine (AL) treatment among HIV-infected children on nevirapine based highly active antiretroviral therapy (HAART) and HIV-non-infected children that were positive for Plasmodium falciparummalaria parasites. Methods: This is a multi-centered, prospective, non-randomized, open-labelled study with two arms consisting of HIV- infected children on nevirapine-based HAART (NVP-arm; n=32) and HIV-non infected children (control-arm; n=40). Both groups of patients were treated with ALafter microscopic confirmation of P. falciparum and were actively monitored for 28 days for efficacy and safety. Primary outcome was Adequate Clinical and Parasitological Response (ACPR) after treatment with ALby day Results: Day 28 ACPR was lower in the NVP-arm (90%) compared to the control-arm (100%) of the study. In the NVP- arm of the study, 5% of cases had early treatment failure and 5% had late parasitological failure. The cumulative risk of developing recurrent malaria in NVP-arm was not statistically significantly higher than in the control-arm (P= 0.07). The reported potential adverse reactions to ALwere mild and included cough, pyrexia, anorexia, and abdominal pain. The cumulative risk of developing cough, pyrexia, anorexia and abdominal pain between NVP-arm compared to the control-arm was not statistically significant (Hazard ratio [HR], 0.51, 0.79 and 0.37 [95% confifidence interval {CI}, 0.04–5.26, 0.07-9.32, and 0.04- 3.56]; P= 1.000, 1.000, and 0.637) respectively. Conclusion: Treatment of uncomplicated malaria with AL was safe and effffective after 28 days of follow-up in HIV- infected children on NVP. Nevirapine based HAARTmay, however, lead to delayed parasite clearance in children treated with AL.

Molecular profiling of the artemisinin resistance Kelch 13 gene in Plasmodium falciparum from Nigeria.

Accurate assessment and monitoring of the Plasmodium falciparum Kelch 13 (pfk13) gene associated with artemisinin resistance is critical to understand the emergence and spread of drug-resistant parasites in malaria-endemic regions. In this study, we evaluated the genomic profile of the pfk13 gene associated with artemisinin resistance in P. falciparum in Nigerian children by targeted sequencing of the pfk13 gene. Genomic DNA was extracted from 332 dried blood (DBS) spot filter paper samples from three Nigerian States. The pfk13 gene was amplified by nested polymerase chain reaction (PCR), and amplicons were sequenced to detect known and novel polymorphisms across the gene. Consensus sequences of samples were mapped to the reference gene sequence obtained from the National Center for Biotechnology Information (NCBI). Out of the 13 single nucleotide polymorphisms (SNPs) detected in the pfk13 gene, five (F451L, N664I, V487E, V692G and Q661H) have not been reported in other endemic countries to the best of our knowledge. Three of these SNPs (V692G, N664I and Q661H) and a non-novel SNP, C469C, were consistent with late parasitological failure (LPF) in two States (Enugu and Plateau States). There was no validated mutation associated with artemisinin resistance in this study. However, a correlation of our study with in vivo and in vitro phenotypes is needed to establish the functional role of detected mutations as markers of artemisinin resistance in Nigeria. This baseline information will be essential in tracking and monitoring P. falciparum resistance to artemisinin in Nigeria.

Clinical Efficacy of Artemether-Lumefantrine Artesunate-Amodiaquine of Children from Three Chadian Provinces with Acute of Uncomplicated <i>Falciparum malariae</i> from 6 Months to 5 Years

Introduction: Artemisinin-based combination therapies are the first-line antimalarial drugs used to treat uncomplicated Plasmodium falciparum malaria in many endemic countries worldwide. In Chad, since the adoption of artemisinin-based combination therapy (ACTs) in its first-line treatment policy for uncomplicated malaria in 2005, Artemether-Lumefantrine and Artesunate-Amodiaquine have been used in many hospitals and health centers. The main objective of this study was to provide the baseline data of Artemether-Lumefantrine and Artesunate-Amodiaquine efficacy in three regions where many people suffered from malaria disease. Material and Methods: The baseline efficacy of two combination therapies was evaluated between January and April 2020 in Mosoro, Mondou and Dourbali Provinces in Chad. A two-arm single cohort study was conducted to assess the clinical efficacy of artesunate-amodiaquine and artemether-lumefantrine for the treatment of 1113 children aged from 6 to 59 months with uncomplicated Falciparum malariae diagnosed by thick blood smear examination, using the World Health Organization validated protocol. Results: On day 3, all patients in both groups had cleared parasitemia, after treatment, the patients presented a higher hemoglobin level in both groups artemether-lumefantrine (10.97 ± 1.39) and artesunate-amodiaquine (11.87 ± 1.81), respectively. On day 28, all patients had adequate clinical and parasitological responses with 99.82% of artesunate-amodiaquine and 99.10% of artemether-lumefantrine. Overall, both drugs were well tolerated at the clinical and biological level, no late parasitological failures have been recorded in artemether-lumefantrine and artesunate-amodiaquine groups, also both forms of Artemisinin-based combination therapy were still effective and safe in the treatment of uncomplicated P. falciparum malaria in Chad.

Dynamic changes in genetic diversity, drug resistance mutations, and treatment outcomes of falciparum malaria from the low-transmission to the pre-elimination phase on the islands of S\xe3o Tom\xe9 and Pr\xedncipe

BackgroundWith effective vector control and case management, substantial progress has been made towards eliminating malaria on the islands of São Tomé and Príncipe (STP). This study assessed the dynamic changes in the genetic diversity of Plasmodium falciparum, the anti-malarial drug resistance mutations, and malaria treatment outcomes between 2010 and 2016 to provide insights for the prevention of malaria rebounding.MethodsPolymorphic regions of merozoite surface proteins 1 and 2 (msp1 and msp2) were sequenced in 118 dried blood spots (DBSs) collected from malaria patients who had visited the Central Hospital in 2010–2016. Mutations in the multi-drug resistance I (pfmdr1), chloroquine resistance transporter (pfcrt), and kelch 13 (pfk13) genes were analysed by polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP) and sequencing in 111 DBSs. A total of 7482 cases that completed a 28-day follow-up were evaluated for treatment outcomes based on the microscopic results. Regression models were used to characterize factors associated with levels of parasite density and treatment failures.ResultsParasite strains in STP showed significant changes during and after the peak incidence in 2012. The prevalent allelic type in msp1 changed from K1 to MAD20, and that in msp2 changed from 3D7/IC to FC27. The dominant alleles of drug-resistance markers were pfmdr1 86Y, 184F, D1246, and pfcrt 76 T (Y-F-D-T, 51.4%). The average parasite density in malaria cases declined threefold from low-transmission (2010–2013) to pre-elimination period (2014–2016). Logistic regression models showed that patients with younger age (OR for age = 0.97–0.98, p < 0.001), higher initial parasite density (log10-transformed, OR = 1.44, p < 0.001), and receiving quinine treatment (compared to artemisinin-based combination therapy, OR = 1.91–1.96, p < 0.001) were more likely to experience treatment failures during follow-up.ConclusionsPlasmodium falciparum in STP had experienced changes in prevalent strains, and increased mutation frequencies in drug-resistance genes from the low-transmission to the pre-elimination settings. Notably, patients with younger age and receiving quinine treatment were more likely to show parasitological treatment failure during follow-up. Therapeutic efficacy should be carefully monitored to inform future treatment policy in STP.

In vivo efficacy and safety of artemether\u2013lumefantrine and amodiaquine\u2013artesunate for uncomplicated Plasmodium falciparum malaria in Mozambique, 2018

BackgroundArtemisinin-based combination therapy (ACT) has been the recommended first-line treatment for uncomplicated malaria in Mozambique since 2006, with artemether–lumefantrine (AL) and amodiaquine–artesunate (AS–AQ) as the first choice. To assess efficacy of currently used ACT, an in vivo therapeutic efficacy study was conducted.MethodsThe study was conducted in four sentinel sites: Montepuez, Moatize, Mopeia and Massinga. Patients between 6 and 59 months old with uncomplicated Plasmodium falciparum malaria (2000–200,000 parasites/µl) were enrolled between February and September of 2018, assigned to either an AL or AS–AQ treatment arm, and monitored for 28 days. A Bayesian algorithm was applied to differentiate recrudescence from new infection using genotyping data of seven neutral microsatellites. Uncorrected and PCR-corrected efficacy results at day 28 were calculated.ResultsTotals of 368 and 273 patients were enrolled in the AL and AS–AQ arms, respectively. Of these, 9.5% (35/368) and 5.1% (14/273) were lost to follow-up in the AL and AS–AQ arms, respectively. There were 48 and 3 recurrent malaria infections (late clinical and late parasitological failures) in the AL and AS–AQ arms, respectively. The day 28 uncorrected efficacy was 85.6% (95% confidence interval (CI) 81.3–89.2%) for AL and 98.8% (95% CI 96.7–99.8%) for AS–AQ, whereas day 28 PCR-corrected efficacy was 97.9% (95% CI 95.6–99.2%) for AL and 99.6% (95% CI 97.9–100%) for AS–AQ. Molecular testing confirmed that 87.4% (42/48) and 33.3% (1/3) of participants with a recurrent malaria infection in the AL and AS–AQ arms were new infections; an expected finding in a high malaria transmission area. Adverse events were documented in less than 2% of participants for both drugs.ConclusionBoth AL and AS–AQ have therapeutic efficacies well above the 90% WHO recommended threshold and remain well-tolerated in Mozambique. Routine monitoring of therapeutic efficacy should continue to ensure the treatments remain efficacious.Trial registration Clinicaltrials.gov: NCT04370977

CLINICAL RESPONSE OF A BRAND OF ARTEMETHER- LUMEFANTRINE IN CHILDREN BELOW FIVE YEARS OLD

Malaria is a major health concern in children aged less than five years old, globally. In Nigeria, it was estimated that 300,000 children die annually from malaria. Thus, this study aims to evaluate the clinical response of a brand of arthemether-lumefantrine (AL) for clearing parasitaemia in children aged less than five years old. This was a prospective study of the clinical and parasitological responses to the treatment of uncomplicated Plasmodium falciparum (P. falciparum) malaria using a popular dispersible brand of AL 20/120 mg. A hundred participants within 6–59 months with P. falciparum malaria were enrolled in the study and participants who could not complete the follow-ups were excluded. The drug was administered to participants following same dosage regimen on days 0, 1, 2 and followed-up on days 3, 7, 14, 21 and 28 in which the participants were assessed clinically and parasitologically. Data was analysed using MS-Excel 2010 and SPSS version 18. Kaplan-Meier survival analysis was used to assess clinical outcomes. The study showed that 73 participants completed the 28 days follow-up while 27 participants were lost to follow-up. Clinical outcome revealed no early treatment failure (ETF), one late clinical failure (LCF), 10 parasitological failures and 62 adequate clinical and parasitological response (ACPF). Clinical response was 84.9%, cumulative success and failure rate was 93.6% and 6.4%, respectively, on day 28. The clinical response of AL was efficacious. The failure rate of 6.4% could likely be as a result of reinfection within the period of follow-up.

Therapeutic efficacy of artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in four malaria endemic states of India

BackgroundMalaria is a major public health problem in India and accounts for about 88% of malaria burden in South-East Asia. India alone accounted for 2% of total malaria cases globally. Anti-malarial drug resistance is one of the major problems for malaria control and elimination programme. Artemether-lumefantrine (AL) is the first-line treatment of uncomplicated Plasmodium falciparum in north eastern states of India since 2013 after confirming the resistance against sulfadoxine-pyrimethamine. In the present study, therapeutic efficacy of artemether-lumefantrine and k13 polymorphism was assessed in uncomplicated P. falciparum malaria.MethodsThis study was conducted at four community health centres located in Koraput district of Odisha, Bastar district of Chhattisgarh, Balaghat district of Madhya Pradesh and Gondia district of Maharashtra state. Patients with uncomplicated P. falciparum malaria were administered with fixed dose combination (6 doses) of artemether-lumefantrine for 3 days and clinical and parasitological response was recorded up to 28 days as per World Health Organization protocol. Nucleotide sequencing of msp1 and msp2 gene was performed to differentiate between recrudescence and reinfection. Amplification and sequencing of k13 propeller gene region covering codon 450–680 was also carried out to identify the polymorphism.ResultsA total 376 malaria patients who fulfilled the enrolment criteria as well as consented for the study were enrolled. Total 356 patients were followed up successfully up to 28 days. Overall, the adequate clinical and parasitological response was 98.9% and 99.4% with and without PCR correction respectively. No case of early treatment failure was observed. However, four cases (1.1%) of late parasitological failure were found from the Bastar district of Chhattisgarh. Genotyping of msp1 and msp2 confirmed 2 cases each of recrudescence and reinfection, respectively. Mutation analysis of k13 propeller gene showed one non-synonymous mutation Q613H in one isolate from Bastar.ConclusionsThe study results showed that artemether-lumefantrine is highly effective in the treatment of uncomplicated P. falciparum malaria among all age groups. No functional mutation in k13 was found in the study area. The data from this study will be helpful in implementation of artemether-lumefantrine in case of treatment failure by artesunate plus sulfadoxine-pyrimethamine.