Uncomplicated Malaria Patients Research Articles

An epidemiological analysis of severe imported malaria infections in Sri Lanka, after malaria elimination

BackgroundImported malaria continues to be reported in Sri Lanka after it was eliminated in 2012, and a few progress to life-threatening severe malaria. MethodsData on imported malaria cases reported in Sri Lanka from 2013 to 2023 were extracted from the national malaria database maintained by the Anti Malaria Campaign (AMC) of Sri Lanka. Case data of severe malaria as defined by the World Health Organization were analysed with regard to patients’ general characteristics and their health-seeking behaviour, and the latter compared with that of uncomplicated malaria patients. Details of the last three cases of severe malaria in 2023 are presented.Results532 imported malaria cases were diagnosed over 11 years (2013–2023); 46 (8.6%) were severe malaria, of which 45 were Plasmodium falciparum and one Plasmodium vivax. Most severe malaria infections were acquired in Africa. All but one were males, and a majority (87%) were 26–60 years of age. They were mainly Sri Lankan nationals (82.6%). Just over half (56.5%) were treated at government hospitals. The average time between arrival of the person in Sri Lanka and onset of illness was 4 days. 29 cases of severe malaria were compared with 165 uncomplicated malaria cases reported from 2015 to 2023. On average both severe and uncomplicated malaria patients consulted a physician equally early (mean = 1 day) with 93.3% of severe malaria doing so within 3 days. However, the time from the point of consulting a physician to diagnosis of malaria was significantly longer (median 4 days) in severe malaria patients compared to uncomplicated patients (median 1 day) (p = 0.012) as was the time from onset of illness to diagnosis (p = 0.042). All severe patients recovered without sequelae except for one who died.ConclusionsThe risk of severe malaria among imported cases increases significantly beyond 5 days from the onset of symptoms. Although patients consult a physician early, malaria diagnosis tends to be delayed by physicians because it is now a rare disease. Good access to expert clinical care has maintained case fatality rates of severe malaria at par with those reported elsewhere.

Day 3 parasitemia and Plasmodium falciparum Kelch 13 mutations among uncomplicated malaria patients treated with artemether-lumefantrine in Adjumani district, Uganda.

Artemisinin resistance threatens malaria control and elimination efforts globally. Recent studies have reported the emergence of Plasmodium falciparum parasites tolerant to artemisinin agents in sub-Saharan Africa, including Uganda. The current study assessed the day 3 parasite clearance and its correlation with P. falciparum K13 propeller gene (pfkelch13) mutations in P. falciparum parasites isolated from patients with uncomplicated malaria under artemether-lumefantrine (AL) treatment. This study enrolled 100 P. falciparum-positive patients to whom AL was prescribed between 09/September/2022 and 06/November/2022. Blood samples were collected in EDTA tubes before treatment initiation (day 0) and on day 3. Parasitemia was assessed by microscopy from blood smears and quantitative polymerase chain reaction (qPCR) from the DNA extracted. The day 0 parasite K13 gene was sequenced using Sanger sequencing. Sequence data were analysed using MEGA version 11 software. The data were analysed using STATA version 15, and the Mann‒Whitney U test was used to compare PCR parasite clearance on day 3 using the comparative CT value method and pfkelch13 mutations. The prevalence of day 3 parasitaemia was 24% (24/100) by microscopy and 63% (63/100) by qPCR from the AL-treated patients. P. falciparum K13-propeller gene polymorphism was detected in 18.8% (15/80) of the day 0 DNA samples. The K13 mutations found were C469Y, 12.5% (10/80); A675V, 2.5% (2/80); A569S, 1.25%, (1/80), A578S, 1.25%, (1/80) and; F491S, 1.25%, (1/80) a new allele not reported anywhere. The C469Y mutation, compared to the wild-type, was associated with delayed parasite clearance p = 0.0278, Hodges-Lehmann estimation 3.2108 on the log scale, (95%CI 1.7076, 4.4730). There was a high prevalence of day 3 P. falciparum among malaria patients treated using artemether-lumefantrine. We conclude the presence of the K13 mutation associated with artemisinin resistance by P. falciparum in Adjumani district, Uganda, necessitates regular surveillance of the effectiveness and efficacy of artemether-lumefantrine in the country.

An elevated level of interleukin-17A in a Senegalese malaria cohort is associated with rs8193038 IL-17A genetic variant

Malaria infection is a multifactorial disease partly modulated by host immuno-genetic factors. Recent evidence has demonstrated the importance of Interleukin-17 family proinflammatory cytokines and their genetic variants in host immunity. However, limited knowledge exists about their role in parasitic infections such as malaria. We aimed to investigate IL-17A serum levels in patients with severe and uncomplicated malaria and gene polymorphism’s influence on the IL-17A serum levels. In this research, 125 severe (SM) and uncomplicated (UM) malaria patients and 48 free malaria controls were enrolled. IL-17A serum levels were measured with ELISA. PCR and DNA sequencing were used to assess host genetic polymorphisms in IL-17A. We performed a multivariate regression to estimate the impact of human IL-17A variants on IL-17A serum levels and malaria outcomes. Elevated serum IL-17A levels accompanied by increased parasitemia were found in SM patients compared to UM and controls (P < 0.0001). Also, the IL-17A levels were lower in SM patients who were deceased than in those who survived. In addition, the minor allele frequencies (MAF) of two IL-17A polymorphisms (rs3819024 and rs3748067) were more prevalent in SM patients than UM patients, indicating an essential role in SM. Interestingly, the heterozygous rs8193038 AG genotype was significantly associated with higher levels of IL-17A than the homozygous wild type (AA). According to our results, it can be concluded that the IL-17A gene rs8193038 polymorphism significantly affects IL-17A gene expression. Our results fill a gap in the implication of IL-17A gene polymorphisms on the cytokine level in a malaria cohort. IL-17A gene polymorphisms also may influence cytokine production in response to Plasmodium infections and may contribute to the hyperinflammatory responses during severe malaria outcomes.

Characterisation of populations at risk of sub-optimal dosing of artemisinin-based combination therapy in Africa.

Selection of resistant malaria strains occurs when parasites are exposed to inadequate antimalarial drug concentrations. The proportion of uncomplicated falciparum malaria patients at risk of being sub-optimally dosed with the current World Health Organization (WHO) recommended artemisinin-based combination therapies (ACTs) is unknown. This study aims to estimate this proportion and the excess number of treatment failures (recrudescences) associated with sub-optimal dosing in Sub-Saharan Africa. Sub-populations at risk of sub-optimal dosing include wasted children <5 years of age, patients with hyperparasitaemia, pregnant women, people living with HIV, and overweight adults. Country-level data on population structure were extracted from openly accessible data sources. Pooled adjusted Hazard Ratios for PCR-confirmed recrudescence were estimated for each risk group from published meta-analyses using fixed-effect meta-analysis. In 2020, of the estimated 153.1 million uncomplicated P. falciparum malaria patients in Africa, the largest risk groups were the hyperparasitaemic patients (13.2 million, 8.6% of uncomplicated malaria cases) and overweight adults (10.3 million, 6.7% of uncomplicated cases). The estimated excess total number of treatment failures ranged from 0.338 million for a 98% baseline ACT efficacy to 1.352 million for a 92% baseline ACT efficacy. Our study shows that an estimated nearly 1 in 4 people with uncomplicated confirmed P. falciparum malaria in Africa are at risk of receiving a sub-optimal antimalarial drug dosing. This increases the risk of antimalarial drug resistance and poses a serious threat to malaria control and elimination efforts. Changes in antimalarial dosing or treatment duration of current antimalarials may be needed and new antimalarials development should ensure sufficient drug concentration levels in these sub-populations that carry a high malaria burden.

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

Low frequency of Plasmodium falciparum hrp2/3 deletions from symptomatic infections at a primary healthcare facility in Kilifi, Kenya.

There is a growing concern for malaria control in the Horn of Africa region due to the spread and rise in the frequency of Plasmodium falciparum Histidine-rich Protein (hrp) 2 and 3 deletions. Parasites containing these gene deletions escape detection by the major PfHRP2-based rapid diagnostic test. In this study, the presence of Pfhrp2/3 deletions was examined in uncomplicated malaria patients in Kilifi County, from a region of moderate-high malaria transmission. 345 samples were collected from the Pingilikani dispensary in 2019/2020 during routine malaria care for patients attending this primary health care facility. The Carestart™ RDT and microscopy were used to test for malaria. In addition, qPCR was used to confirm the presence of parasites. In total, 249 individuals tested positive for malaria by RDT, 242 by qPCR, and 170 by microscopy. 11 samples that were RDT-negative and microscopy positive and 25 samples that were qPCR-positive and RDT-negative were considered false negative tests and were examined further for Pfhrp2/3 deletions. Pfhrp2/3-negative PCR samples were further genotyped at the dihydrofolate reductase (Pfdhfr) gene which served to further confirm that parasite DNA was present in the samples. The 242 qPCR-positive samples (confirmed the presence of DNA) were also selected for Pfhrp2/3 genotyping. To determine the frequency of false negative results in low parasitemia samples, the RDT- and qPCR-negative samples were genotyped for Pfdhfr before testing for Pfhrp2/3. There were no Pfhrp2 and Pfhrp3 negative but positive for dhfr parasites in the 11 (RDT negative and microscopy positive) and 25 samples (qPCR-positive and RDT-negative). In the larger qPCR-positive sample set, only 5 samples (2.1%) were negative for both hrp2 and hrp3, but positive for dhfr. Of the 5 samples, there were 4 with more than 100 parasites/µl, suggesting true hrp2/3 deletions. These findings revealed that there is currently a low prevalence of Pfhrp2 and Pfhrp3 deletions in the health facility in Kilifi. However, routine monitoring in other primary health care facilities across the different malaria endemicities in Kenya is urgently required to ensure appropriate use of malaria RDTs.

What is the role of autoantibodies in post-artesunate delayed hemolysis?

We read with great interest the recent publication by Kurth et al.1 that highlights an interesting aspect of post-artesunate delayed hemolysis (PADH) among uncomplicated malaria patients treated with oral artemisinin-based combination therapy (ACT). Post-treatment delayed hemolysis has increasingly been observed, especially among travellers from non-endemic areas.2 Besides the well-known ‘pitting’ mechanism, the article discussed that ACT might produce drug-autoantibodies that contribute to post-treatment hemolysis. We would like to discuss the possible role of autoantibodies against red blood cells (RBC) as a pathophysiologic mechanism of PADH and the clinical implication of corticosteroid therapy for patients with PADH. Camprubí et al. (2019) reported a case of PADH in a splenectomized patient with a positive direct antiglobulin test (DAT); this raised a critical discussion as the ‘pitting’ mechanism cannot explain the hemolysis in this patient.3 The phenomenon may be explained by three hypotheses involving drug-induced immune hemolytic anaemia. First, the drug, acting as a hapten, attaches to the RBC membrane and induces autoantibody reactions. Second, the immune complex mechanism involves anti-drug antibodies produced during artesunate treatment in previous infections. Once artesunate is administered in subsequent infections, a drug-anti-drug immune complex is formed and randomly binds to the RBC surface, which activates complement fixation and opsonization, leading to cell lysis. Lastly, it assumes that the drug may act as a coating for the RBCs. If IgG antibodies against the drug are present, the reaction to the drug-coated RBCs can cause hemolysis. The immune complex mechanism may explain the high levels of autoantibodies found among ‘semi-immune’ patients of African descent who developed PADH in the recent study by Kurth et al.

A cross-sectional study on demography, clinical presentation, knowledge, attitude, practice, and treatment seeking behavior among uncomplicated Plasmodium falciparum malaria patients at a tertiary care hospital in Eastern India

Background: Malaria continues to be a public health problem in India including Kolkata, West Bengal. Timely recognition of the symptoms of malaria, attending health-care facilities, prompt diagnosis and appropriate treatment can only prevent fatal outcome. Aims and Objectives: The aim of the study was to explore the knowledge, attitude, practice, and treatment seeking behavior of uncomplicated Plasmodium falciparum malaria patients attending a tertiary care hospital in Kolkata. Materials and Methods: This cross-sectional and observational study was conducted at a tertiary care hospital in Kolkata after receiving ethics committee approval. Each consecutive consented uncomplicated P. falciparum malaria patients of all age group and gender excluding sick patients, pregnant women, and infants were interviewed with a predesigned and pretested semi-structured questionnaire to elicit personal history, clinical complaints, knowledge, and awareness about malaria, preventive measures, and treatment seeking behavior along with history of medication use. Results: Out of total 112 study participants, majority were young (mean age 37.5 ± 13.41 years), 50.89% had no formal education, mostly engaged in small business (33.03%) or in manual labor. Majority (74.10%) used antipyretic and analgesics for fever and 51.78% consulted a local private physician first before attending government hospital which they usually prefer. Many (58.92%) knew mosquito as vector but only 7.14% regularly used mosquito bed nets. Use of antibiotics (barring antimalarials) was 11.60%. Conclusion: The study participants showed a good knowledge about malaria, its transmission, and clinical symptomatology but a mismatch with attitude and practice in disease prevention and treatment seeking behavior was noted. More awareness campaign should be conducted among general public to improve the same.

Hematological Parameters Variations Among Patients With Uncomplicated Plasmodium falciparum Infection in Cambodia

Introduction: The prevalence of anemia among patients with malaria is very common from subsequent erythrocytes destruction and should be managed most appropriately. This study aimed to explore the changes in hematological parameters and their underlying influence among people with uncomplicated Plasmodium falciparum infection. Methods: A cross-sectional study was conducted among uncomplicated malaria patients infected by P. falciparum on community-based active screening days in one of the highest malaria hot-spot areas of northwestern Cambodia. Descriptive statistics, and student t-tests were used to analyze the data. Results: Among 103 malaria blood samples, the results showed that most participants had thrombocytopenia (84.5%). More than onehalf of the participants presented normal levels of the following hematological parameters: red blood cells, hemoglobin, hematocrit, mean corpuscular volume (MCV) and red cell distribution width (RDW). A significant correlation was noted between parasite counts and three body mass index (BMI) groups (P=0.047). Next, a strong association was also seen between parasite counts and body temperature (P = 0.03). Statistically significant differences in parasite count were observed across three levels of neutrophil (P=0.005), lymphocyte (P=0.001), eosinophil (P&lt;0.001), absolute lymphocyte (P=0.001) and absolute eosinophil (P&lt;0.001) counts. Conclusion: The results of this study revealed the significant role of hematological parameters in predicting the presence of malaria infection, parasite density, and forecasting adverse consequences of malaria, together with the underlying risk factors.

Observation of Malaria Treatment with Dihydroartemisinin-Piperaquine Combination at Primary Health Care

Dihydroartemisinin-Piperaquine (DHP) combination is the first-line treatment for uncomplicated malaria in Indonesia and has been used since 2010. This study was conducted to determine the efficacy of DHP combination for uncomplicated malaria treatment in a community-based evaluation. Recruitment was done by active or passive case detection. All uncomplicated malaria patients were treated with DHP once a day, for 3 days, administered orally (as is done in primary health care). Patients were followed up until day 28 post-treatment. The primary end point was a 28-day cure rate. In this study, 484 subjects were screened through active and passive cases detection. A total of 45 subjects infected by P. vivax and 2 subjects infected by P. falciparum agreed to participate through written informed consent. There was no difference between clinical malaria and asymptomatic malaria in all analyzed characteristics. One patient had a D3 parasite density greater than 25% D0, although no parasites were found on the following day (D4). This study found 46 patients (97.9%) who had adequate clinical and parasitological responses. No adverse event was reported during the follow up of this study. DHP was effective, safe, and well tolerated in the treatment of uncomplicated malaria at primary health care.

Total parasite biomass but not peripheral parasitaemia is associated with endothelial and haematological perturbations in Plasmodium vivax patients.

Plasmodium vivax is the major cause of human malaria in the Americas. How P. vivax infection can lead to poor clinical outcomes, despite low peripheral parasitaemia, remains a matter of intense debate. Estimation of total P. vivax biomass based on circulating markers indicates existence of a predominant parasite population outside of circulation. In this study, we investigate associations between both peripheral and total parasite biomass and host response in vivax malaria. We analysed parasite and host signatures in a cohort of uncomplicated vivax malaria patients from Manaus, Brazil, combining clinical and parasite parameters, multiplexed analysis of host responses, and ex vivo assays. Patterns of clinical features, parasite burden, and host signatures measured in plasma across the patient cohort were highly heterogenous. Further data deconvolution revealed two patient clusters, here termed Vivaxlow and Vivaxhigh. These patient subgroups were defined based on differences in total parasite biomass but not peripheral parasitaemia. Overall Vivaxlow patients clustered with healthy donors and Vivaxhigh patients showed more profound alterations in haematological parameters, endothelial cell (EC) activation, and glycocalyx breakdown and levels of cytokines regulating different haematopoiesis pathways compared to Vivaxlow. Vivaxhigh patients presented more severe thrombocytopenia and lymphopenia, along with enrichment of neutrophils in the peripheral blood and increased neutrophil-to-lymphocyte ratio (NLCR). When patients' signatures were combined, high association of total parasite biomass with a subset of markers of EC activation, thrombocytopenia, and lymphopenia severity was observed. Finally, machine learning models defined a combination of host parameters measured in the circulation that could predict the extent of parasite infection outside of circulation. Altogether, our data show that total parasite biomass is a better predictor of perturbations in host homeostasis in P. vivax patients than peripheral parasitaemia. This supports the emerging paradigm of a P. vivax tissue reservoir, particularly in the haematopoietic niche of bone marrow and spleen.

Significant differences in Fc\u03b3RIIa, Fc\u03b3RIIIa and Fc\u03b3RIIIb genes polymorphism and anti-malarial IgG subclass pattern are associated with severe Plasmodium falciparum malaria in Saudi children

BackgroundThe FcγRs genotypes have been reported to play a key role in the defence against malaria parasites through both cellular and humoral immunity. This study aimed to investigate the possible correlation between FcγR (IIa, IIIa, and IIIb) genes polymorphism and the clinical outcome for anti‐malarial antibody response of Plasmodium falciparum infection among Saudi children.MethodsA total of 600 volunteers were enrolled in this study, including 200 malaria-free control (MFC) subjects, 218 patients with uncomplicated malaria (UM) and 182 patients with severe malaria (SM). The FcγR genotypes were analysed using PCR amplification methods, and measurements of immunoglobulin were determined using enzyme-linked immunosorbent assay (ELISA) technique.ResultsThe data revealed that the FcγRIIa-R/R131 showed a statistically significant association with SM patients when compared to UM patients. Furthermore, higher levels of IgG1, IgG2, and IgG4 were associated with the FcγRIIa-H/H131 genotype among UM patients. Although the FcγRIIa-F/V176 genotype was not associated with UM, it showed a significant association with severe malaria. Interestingly, the FcγRIIIa-V/V176 genotype offered protection against SM. Moreover, SM patients carrying the FcγRIIIa-F/F genotype showed higher levels of AMA-1-specific IgG2 and IgG4 antibodies. The FcγRIIIb-NA1/NA1 and FcγRIIIb-NA2/NA2 genotypes did not show significant differences between the UM and the MFC groups. However, the genotype FcγRIIIb-NA2/NA2 was statistically significantly associated with SM patients.ConclusionsThe data presented in this study suggest that the influence of the FcγRIIa-R/R131, FcγRIIIa-F/F176 and FcγRIIIb-NA2/NA2 genotypes are statistically significantly associated with SM patients. However, the FcγRIIa-H/H13 and FcγRIIIa-V/V176 genotypes have demonstrated a protective effect against SM when compared to UM patients. The impact of the FcyR (IIa, IIIa and IIIb) gene variants and anti-malaria IgG subclasses play an important role in susceptibility to malaria infection and disease outcome in Saudi children.

Temporal evolution of sulfadoxine-pyrimethamine resistance genotypes and genetic diversity in response to a decade of increased interventions against Plasmodium falciparum in northern Ghana

BackgroundAnti-malarial drug resistance remains a key concern for the global fight against malaria. In Ghana sulfadoxine-pyrimethamine (SP) is used for intermittent preventive treatment of malaria in pregnancy and combined with amodiaquine for Seasonal Malaria Chemoprevention (SMC) during the high malaria season. Thus, surveillance of molecular markers of SP resistance is important to guide decision-making for these interventions in Ghana.MethodsA total of 4469 samples from uncomplicated malaria patients collected from 2009 to 2018 was submitted to the Wellcome Trust Sanger Institute, UK for DNA sequencing using MiSeq. Genotypes were successfully translated into haplotypes in 2694 and 846 mono infections respectively for pfdhfr and pfdhps genes and the combined pfhdfr/pfdhps genes across all years.ResultsAt the pfdhfr locus, a consistently high (> 60%) prevalence of parasites carrying triple mutants (IRNI) were detected from 2009 to 2018. Two double mutant haplotypes (NRNI and ICNI) were found, with haplotype NRNI having a much higher prevalence (average 13.8%) than ICNI (average 3.2%) across all years. Six pfdhps haplotypes were detected. Of these, prevalence of five fluctuated in a downward trend over time from 2009 to 2018, except a pfdhps double mutant (AGKAA), which increased consistently from 2.5% in 2009 to 78.2% in 2018. Across both genes, pfdhfr/pfdhps combined triple (NRNI + AAKAA) mutants were only detected in 2009, 2014, 2015 and 2018, prevalence of which fluctuated between 3.5 and 5.5%. The combined quadruple (IRNI + AAKAA) genotype increased in prevalence from 19.3% in 2009 to 87.5% in 2011 before fluctuating downwards to 19.6% in 2018 with an average prevalence of 37.4% within the nine years. Prevalence of parasites carrying the quintuple (IRNI + AGKAA or SGEAA) mutant haplotypes, which are highly refractory to SP increased over time from 14.0% in 2009 to 89.0% in 2016 before decreasing to 78.9 and 76.6% in 2017 and 2018 respectively. Though quintuple mutants are rising in prevalence in both malaria seasons, together these combined genotypes vary significantly within season but not between seasons.ConclusionsDespite high prevalence of pfdhfr triple mutants and combined pfdhfr/pfdhps quadruple and quintuple mutants in this setting SP may still be efficacious. These findings are significant as they highlight the need to continuously monitor SP resistance, particularly using deep targeted sequencing to ascertain changing resistance patterns.

Genetic profiles of glucose-6-phosphate dehydrogenase among uncomplicated malaria patients in malaria endemic region of Thailand

Genetic profiles of glucose-6-phosphate dehydrogenase among uncomplicated malaria patients in malaria endemic region of Thailand

Artemether\u2013lumefantrin treatment adherence among uncomplicated plasmodium falciparum malaria patients, visiting public health facilities in AsgedeTsimbla district, Tigray, Ethiopia: a cross-sectional study

BackgroundEthiopia has set a goal to eliminate malaria by 2030; Artemether–lumefantrine (AL) is put as one of the cornerstone strategies for uncomplicated plasmodium falciparum malaria treatment. However, only focusing on prescribing of the treatment without assessing patients’ adherence could lead to the resistance of the drug. In Ethiopia, there is limited evidence about patients’ adherence to AL and its influencing factors. Therefore, this study aimed at addressing this information gap.MethodsA health facility based cross-sectional study was employed. Participants were selected using simple random sampling technique from registration books of the public health facilities in AsgedeTsimbla. Data were collected from March 24th to April 30th, 2018. We interviewed participants using a pre-tested structured questionnaire, and the blister pack was also inspected at their homes on day 4. Data were entered into Epi-Info and analyzed using SPSS 21. Odds ratios with 95% Confidence Intervals were estimated and the level of significance was declared at p-value ≤ 0.05.ResultsA total of 384 study participants were interviewed with a response rate of 95.5%. The overall AL adherence was 53.6% (95% CI 48.4–58.3%). Children aged < 5 years [AOR: 0.4, 95% CI (0.2–0.8)], and being treated in health post [AOR: 0.3, 95% CI (0.1–0.5)] were more likely to show AL adherence whereas illiteracy [AOR: 9.4, 95% CI (4.2–21.3)], didn’t know the consequence of discontinued AL [AOR: 4.0, 95% CI (2.1–7.6)], had concomitant drugs [AOR: 2.5, 95% CI (1.4–4.5)], and stopped/saved drug when improved before tablet got finished [AOR: 3.2, 95% CI (1.7–5.9)] were factors less likely to be associated with AL adherence.ConclusionAL adherence was low. Children aged < 5 years, and being treated in health post were determinants of AL adherence whereas illiteracy, didn’t know the consequence of discontinued the drug, had concomitant drugs, and stopped/saved drug when improved before tablet got finished were factors that hindered the AL adherence. Stakeholders should emphasize designing appropriate strategies including educational interventions to increase the AL adherence and prevent drug resistance. Further research should be conducted to evaluate AL resistance.

Persistence of Markers of Chloroquine Resistance in Plasmodium falciparum in Bangladesh.

The control of malaria, in terms of drug resistance, remains a significant global challenge, with Bangladesh, a malaria-endemic country, being no exception. The aim of this study was to explore antimalarial resistance in Bangladesh by molecular analysis of Plasmodium falciparum chloroquine resistance transporter (pfcrt) and P. falciparum multidrug resistance transporter 1 (pfmdr1) genetic markers of P. falciparum. Samples were obtained from uncomplicated malaria patients between 2009 and 2014 from six malaria-endemic districts. Based on parasite transmission intensity, the endemic districts were divided into high-transmission (Chittagong Hill Tracts [CHT]) and low-transmission (non-CHT) regions. Falciparum malaria-positive isolates were genotyped for K76T of the pfcrt gene, and N86Y and Y184F of the pfmdr1 gene: in total, 262 P. falciparum clinical isolates were analyzed. In CHT areas, the prevalence of polymorphisms was 70.6% for 76T, 14.4% for 86Y, and 7.8% for 184F. In non-CHT areas, 76T and 86Y mutations were found in 78.0% and 19.5% of the samples, respectively, whereas no 184F mutations were observed. We compared our data with previous similar molecular observations, which shows a significant decrease in pfcrt 76T mutation prevalence. No pfmdr1 amplification was observed in any of the samples suggesting an unaltered susceptibility to amino alcohol drugs such as mefloquine and lumefantrine. This study provides an updated assessment of the current status of pfcrt and pfmdr1 gene mutations in Bangladesh, and suggests there is persistent high prevalence of markers of resistance to aminoquinoline drugs.

Efficacy of Artemether-Lumefantrine on various Plasmodium falciparum Kelch 13 and Pfmdr1 genes isolated in Ghana

IntroductionArtemether-Lumefantrine (A-L) remains the drug of choice for the treatment of uncomplicated malaria in Ghana. However, the pharmaco-activity of A-L has not been assessed on various Plasmodium falciparum Kelch 13 and Pfmdr1 genes. Therefore, this study sought to determine the therapeutic efficacy of A-L on P. falciparum parasites isolated from Ghana. MethodsThe clinical study was done in Ga West Municipality, Ghana, where 78 uncomplicated malaria patients were recruited with prior consent. The patients were treated orally with A-L according to national treatment guidelines. Baseline parasitaemia was determined before treatment and 8-hourly parasitaemia posttreatment were determined till initial clearance of parasitaemia and at days 7, 14, 21, and 28. Kelch 13 and Pfmdr1 genes were genotyped by sequencing using baseline samples. Parasite clearance characteristics were determined using Parasite Clearance Estimator beta 0.9 application. ResultsFive Kelch 13 (F446I, S466N, R539I, A578S, and A676S) and three Pfmdr1 mutations (N86Y, Y184F and D1246Y) were identified in 78 infected samples. About 8% of the samples contained two Pfmdr1 double mutations (N86Y & D1246Y and Y184F & N86Y). Additionally, three samples (3.8%) were found to contain both Kelch 13 mutations and Pfmdr1 wild type genes. In all patients, parasitaemia persisted within the first 24 h of A-L therapy. However, at hour 40, only two patients were parasitaemic while all patients were aparasitaemic at hour 48. The genotypic profiles of the two persistent parasites at hour 40 were F446I and D1246Y, and R539I, Y184F, and N86Y. The slope half-life of the former was 6.4 h while the latter was 6.9 h and their respective PCT99 were 47.9 h and 49.2 h as well as a clearance rate constants of 0.109 and 0.092 respectively. ConclusionThis study reports the effectiveness of A-L on various P. falciparum mutant alleles. However, continuous surveillance of Kelch 13 mutations and Pfmdr1 gene in Ghana and regular assessment of the therapeutic efficacy of A-L and other artemisinin derivatives is recommended.

Comparative analysis of asexual and sexual stage Plasmodium falciparum development in different red blood cell types

BackgroundRed blood cell (RBC) polymorphisms are suggested to influence the course of Plasmodium falciparum malaria. Whereas some variants have been found to be protective, others have been found to enhance parasite development. This study evaluated the effect of variant haemoglobin (Hb) and ABO blood groups on P. falciparum merozoite invasion, multiplication rates as well as gametocyte development.MethodsApproximately 2.5 mL of venous blood was collected from each participant. Flow cytometry was used to determine the in vitro merozoite invasion rates of NF54 parasites into the blood of 66 non-parasitaemic individuals with variant Hb genotypes (HbSS, HbSC) and blood groups (A, B, O), which were then compared with invasion into HbAA blood. The ex vivo asexual parasite multiplication and gametocyte production rates of parasites from 79 uncomplicated malaria patients with varying Hb genotypes (HbAS, HbAC and HbAA) were also estimated using microscopy.ResultsMerozoite invasion rates were significantly reduced by about 50% in RBCs containing HbSS and HbSC relative to HbAA cells. The presence of blood group O and B reduced the invasion rates of HbSS by about 50% and 60%, respectively, relative to HbSC but the presence of blood group A removed the inhibitory effect of HbSS. The initial parasite densities in uncomplicated malaria patients with Hb genotypes HbAS and HbAC cells were similar but significantly lower than those with genotype HbAA. The ex vivo parasite multiplication rate, gametocytaemia and gametocyte conversion rates followed a similar trend but did not reach statistical significance (p > 0.05).ConclusionsParasite invasion rate into erythrocytes is dependent on both erythrocyte blood group antigen and haemoglobin genotype as blood group O and B provided protection via reduced merozoite invasion in RBCs containing HbSS relative to HbSC. Regardless of haemoglobin type, greater than 70% malaria patients had circulating ring stage parasites that differentiated into stage II gametocytes in 4 days.

High-Performance Liquid Chromatography with Diode Array Detection for the Simultaneous Quantification of Piperaquine and Mefloquine in Human Plasma in Vietnamese Uncomplicated Malaria Patients

A bioanalytical method using high-performance liquid chromatography with diode array detection was developed and validated for quantification of piperaquine and mefloquine in human plasma. After extraction from 200 μL of plasma by using solid phase extraction on MCX-96 well plate; piperaquine, mefloquine and quinine (internal standard) were separated using a mobile phase consisting of trichloroacetic acid 1 mM and trimethylamine 0.025%, pH 3.4-Acetonitrile applying gradient elution on a Poroshell 120, C8 end capped 100 × 4.6 mm, 2.7 μm column at a flow rate of 1.0 mL/min at 35°C. The peaks were monitored with a diode array detection set at a wavelength of 343 nm for piperaquine, quinine and 283 nm for mefloquine. The limit of quantification was 10 ng/mL, 50 ng/ mL for piperaquine and mefloquine, respectively. The method was linear over the range of 10 to 2,000 ng/ml for piperaquine and 50 to 10,000 ng/ml for mefloquine in plasma. The intra, inter assay precision were less than 8% overall quality control ranges for these analytes. The accuracies varied between 99.85% and 104.6% at all quality control levels for piperaquine and mefloquine. The validated method was applied to measure the concentrations of piperaquine, mefloquine in samples collected from 12 uncomplicated malaria patients in Binh Phuoc province, Vietnam.

Genetic Diversity and Multiplicity of Infection in Plasmodium Falciparum Isolates Causing Uncomplicated Malaria Infections in North-East India

Understanding the genetic diversity of Plasmodium falciparum still remains a major obstacle in developing effective malaria control strategies in different geographical regions of North East India. The study was aimed to determine the genetic diversity of P. falciparum merozoite surface protein 1 (mspl) and 2 (msp2) and multiplicity of infection (MOl) from uncomplicated malaria patients from the states of Assam, Manipur and Meghalaya in North East India. A total of sixty six P. falciparum isolates from uncomplicated malaria patients attending various public health centers of northeastern states were collected from September 2015 to December 2018 prior to treatment. Parasite DNA was extracted and mspl and msp2 gene frequencies and diversity were analyzed using allele-specific nested PCR assay followed by sequencmg. Analysis of mspl alleles revealed that Kl allelic family was predominant with 33.34% followed by MAD20 at 18.18%% and R033 at 9.09% respectively. In msp2, the 3D7 family was most highly represented with 50% prevalence against 31.81% for FC27. Multiclonal infections were observed with 26 (39.40%) and 12 (18.18%) patients harboring more than one parasite genotype followed by MOl at 1.12 and 0.95 for mspl and msp2 genes respectively. The present study showed the highest genetic diversity in P. falciparum infected patients in Assam state with multiple clones followed by Meghalaya and Manipur indicating gene flow between the parasite populations within the states due to frequent human migration.