Countries in the Greater Mekong Subregion (GMS) have committed to eliminating malaria by 2030. The success of a national malaria programme’s transition from malaria control to elimination is dependent on the readiness of the health system to implement malaria elimination strategies. Understanding the readiness of health systems and what needs to be adapted is key to identifying barriers in achieving malaria elimination goals. This study aims to assess health system needs for malaria elimination, identify national-level barriers to effective implementation, and provide recommendations for policymakers and programme managers to strengthen strategies through a health system perspective. A multi-country qualitative study was conducted in the GMS. Semi-structured interviews were conducted with 39 stakeholders including national malaria policymakers (n = 5), basic health staff from Ministries of Health (n = 12), managers and field supervisors from malaria implementing partners (n = 16) and personnel from technical agencies (n = 6). Reflexive thematic analysis of national level health system requirements was carried out aligned with themes adapted from the World Health Organization (WHO) health system building blocks. Stakeholders discussed that malaria elimination required inputs from all six WHO health system building blocks at the national level. Major inputs included strong political commitment, targeted interventions for high-risk groups, reliable forecasting and supply chains, skilled workforce, and robust quality assurance. Furthermore, National Malaria Elimination Programmes should expand access to diagnostic kits and medicines and enforce mandatory glucose-6-phosphate dehydrogenase enzyme testing. Stakeholders identified health system barriers such as the lack of targeted interventions in high-risk groups in national policies, incomplete reporting from private sector, lack of experienced workforce for elimination, administrative constraints in supply chain, declining malaria funding from international donors, and poor compliance to regulations for malaria elimination. For malaria elimination in the GMS to succeed, comprehensive health system strengthening across all six building blocks is essential. National programmes must assess national health system readiness for malaria elimination to avoid inefficiencies, financial strain, and unattended gaps, using a systems thinking approach. This study also highlighted the importance of evaluating the national programmes from the perspective of health system needs and readiness for successful transitioning from control to elimination phase.

Malaria parasite genomes have been generated predominantly using Illumina short-read sequencing that requires expensive equipment, is time-consuming with complex protocols, and does not adequately interrogate complex genomic regions that harbour important malaria virulence determinants. The portable Oxford Nanopore Technologies MinION platform generates long reads in real time and may overcome these limitations. We present compelling evidence that Nanopore sequencing delivers valuable additional information for malaria parasites with similar data fidelity for single nucleotide variant (SNV) calls compared to standard Illumina whole-genome sequencing. We demonstrate this through sequencing of pure Plasmodium falciparum DNA, mock infections and natural isolates from low-density, asymptomatic infections. Nanopore has low error rates for haploid SNV genotyping and identifies structural variants not detected with short reads. Nanopore genomes can be directly compared to publicly available genomes and produce high-quality end-to-end chromosome assemblies including complex, previously difficult-to-access regions. Nanopore sequencing could expedite whole-genome surveillance of malaria and provide new insights into parasite genome biology.

Abstract Malaria, caused by Plasmodium falciparum spans liver, blood, and mosquito stages, limiting the effectiveness of single-stage vaccines. The PTRAMP-CSS heterodimer, a core component of the essential PCRCR invasion complex, is expressed on merozoites, mature gametocytes, and salivary gland sporozoites, enabling single-antigen targeting across multiple lifecycle stages. Nanobodies against PTRAMP-CSS block merozoite invasion of erythrocytes, reduce mosquito infection in membrane-feeding assays, and inhibit sporozoite invasion of primary human hepatocytes. High-resolution crystal structures of inhibitory and non-inhibitory nanobody-antigen complexes identify conserved inhibitory epitopes and guide the design of bispecific nanobody Fc constructs with enhanced potency. In semi-immune Kenyan CHMI samples, higher baseline IgG to PTRAMP-CSS and Ripr is associated with improved parasite control. By demonstrating conserved vulnerability across all three major lifecycle stages, PTRAMP-CSS offers a realistic path to single-antigen, multistage vaccines and biologics that aim to prevent disease and block transmission.

BackgroundGlobal efforts to control and eventually eliminate malaria have been less effective for Plasmodium vivax relative to Plasmodium falciparum due to its unique biology, including dormant liver stages that cause later relapse, and earlier commitment to transmission stages. After the nationwide distribution of long-lasting insecticide treated nets (LLIN) in Papua New Guinea (PNG), P. vivax initially reduced to low prevalence, but again resurged to levels similar to those before LLIN distributions.MethodTo explore changes in P. vivax population structure and identify sources of resurgence over this period, we applied a previously validated genome-wide SNP barcode to genotype 336 P. vivax isolates obtained from serial cross-sectional surveys conducted over a decade in East Sepik (2005, 2012, 2016) and Madang Province (2006, 2010, 2014).ResultsPopulation genetic analyses of the resulting parasite genotypes revealed contrasting spatiotemporal patterns between the two provinces. In Madang, the complexity of infection, genetic diversity, and population structure varied with prevalence, with a possible population bottleneck and early clonal expansion at low transmission, and rapid recovery of the population with resurgence. In East Sepik, there was a less dramatic impact on the parasite population after prevalence decline, and ongoing transmission of multiple residual lineages throughout the study period. P. vivax decline was also accompanied by an increase in genetic differentiation between the two areas, which reduced with resurgence suggesting changes in parasite migration between areas associated with prevalence.ConclusionThe earlier implementation of LLIN in East Sepik, smaller rebound, heterogeneity in transmission and relative isolation, compared to Madang may have contributed to these differing patterns. The results demonstrate that long term sustained control efforts are essential to make a lasting impact on the P. vivax population, and that SNP barcodes can provide valuable insights into parasite transmission dynamics as a result of control efforts.

BACKGROUND:Knowledge of the genetic diversity of Plasmodium vivax antigen vaccine candidates can offer valuable insights into antigens targeted by host immunity and their utility as vaccine candidates. We previously catalogued the genetic diversity of DBP, MSP1, and members of the RBP family. Here we report the diversity of 14 additional P vivax vaccine candidates to identify polymorphic domains and immune selection, to guide selection of alleles for vaccine development. METHODS:A total of 289 of 353 publicly available P vivax whole genome sequences from Asia, the Americas, and Oceania passed a stringent variant-calling pipeline. Measures of diversity and balancing selection were calculated both across linear gene sequences and 3-dimensional (3D) proteins. RESULTS:The blood-stage antigens AMA1, CyRPA, RBP1a, and P41 exhibited high genetic diversity and signatures of balancing selection on both linear and 3D structures. These signatures were consistent across all endemic regions, suggesting that these polymorphic loci are under immune selection. In contrast, CSP, TRAP, MSP4, MSP9, MSP10, GAMA, S12, ARP, S25, and S28 antigens showed low to intermediate genetic diversity and variable patterns among countries. Haplotype networks identified common variants that may represent antigenically distinct clusters. Importantly, sequences from the vaccine strain Sal-1 have extremely low global frequencies. CONCLUSIONS:AMA1, CyRPA, RBP1a, and P41 are under strong immune selection, while other antigens show limited diversity. Current vaccine formulations based on Sal-1 may have limited efficacy. Our results provide a framework for vaccine developers to select more common variants.

Prioritising malaria vaccine targets requires understanding immunity to genetically and structurally diverse parasite antigens, influencing antibody measurements and durability. We measured total IgG levels to 25 Plasmodium falciparum antigens and assessed their association with protection and antigen features. Antibodies were quantified in two longitudinal cohorts of Papua New Guinean children (5-14 years; n=647) experiencing high or moderate transmission. Associations between antibody levels and time to first clinical malaria episode were evaluated using Cox regression and Bayesian antibody-kinetics models, incorporating antigen genetic diversity and structural properties. In high-transmission settings, antibody levels were elevated and stable, with the strongest protection observed for conserved, low-diversity antigens dominated by the 3D7-reference-matching haplotypes and enriched for intrinsically disordered and alpha-helical regions. In moderate transmission, antibody levels were variable, decayed over time, and reflected recent exposure. These findings identify antigen diversity as a key modifier of malaria immunity and underscore the importance of antigen features.

Background Plasmodium vivax poses a major obstacle to malaria elimination because this parasite can lie dormant in the liver for weeks to months before reactivating and causing a relapse of infection. These dormant forms (hypnozoites) cannot be detected using standard diagnostics, but P vivax exposure in the previous 9 months and, by proxy, hypnozoite carriage, can be inferred using serological markers. In this study, we aimed to examine how genetic variation in P vivax affects the utility of these markers and whether redesigned antigens could improve performance. Methods In this observational diagnostic accuracy study, we analysed global P vivax genetic data to assess variation in leading serological markers (n=14). Accordingly, we expressed new haplotypes that better reflect global sequence diversity for eight antigens, compared with the commonly used reference strain (Sal-1). Antibody responses against these were tested using samples from cohorts in Brazil and Thailand, with magnitude assessed in relation to how recently participants had a qPCR-detectable blood-stage P vivax infection. We compared the ability of the haplotypes versus the reference to correctly identify individuals infected within the previous 9 months. Findings Extensive global genetic diversity was identified in two P vivax antigens, MSP5 (π=14·8 × 10-3) and DBPII (π=7·7 × 10-3). Several antigens had large numbers of circulating haplotypes, with the percentage with similar sequence identity to the reference Sal-1 ranging from 0·4% (MSP5) to 99% (S16). Samples for immune analysis were previously collected between April 2013 and June 2014, with 774 and 923 participants included in the current analysis from Thailand and Brazil, respectively. Two antigens showed strong differences in immunogenicity by region and construct (RBP2a and DBPII). However, for most proteins (five of eight: MSP5, RiPR, PTEX150, Pv-fam-a, and RBP2b), these differences had no significant effect on the accuracy of identifying recent exposure. Affected performance (eg, RBP2a) was overcome by adding multiple antigens into the classification model. Interpretation Even highly diverse antigens can be effective serological markers. Our findings highlight the importance of testing the effect of genetic diversity and suggest practical strategies to ensure consistent performance across regions. Funding Australian National Health and Medical Research Council.

With resistance to current frontline antimalarial treatments rapidly emerging in malaria endemic regions, there is an urgent need to identify new antimalarial compounds with novel mechanisms of action. Currently, no clinically used antimalarials target erythrocyte invasion, the process by which the short-lived, extracellular merozoite form of Plasmodium falciparum parasites enters a host erythrocyte. Following invasion, the parasite grows and then divides to form a schizont, containing merozoites that exit the host cell and invade new erythrocytes. To identify novel egress and invasion inhibitors, we screened the Medicines for Malaria Venture COVID Box (160 compounds) and Global Health Priority Box (240 compounds). Parasites were treated with the compounds at 1 μM during the egress and invasion period and across both libraries, 20 invasion inhibitors and two partial egress inhibitors were identified. A comparison of the growth IC50 and invasion IC50 of each hit compound revealed that invasion inhibition is likely central to the parasiticidal mechanism of six of the compounds, as their IC50s for growth and invasion were similar. Of these six inhibitors, two (MMV006931 and MMV024850) were found to directly block the invasion of mechanically purified merozoites. We sought to identify the protein targets of these compounds through resistance selection and subsequent whole genome sequencing. We were able to select parasites with robust resistance to MMV006931 but not MMV024850. Genome sequencing of clonal MMV006931-resistant parasites identified mutations in the P. falciparum sterol exporter PfNCR1, which helps eliminate excess cholesterol from the parasite's plasma membrane. By demonstrating that MMV006931 sensitises parasites to lysis by a sterol-dependent detergent, we confirmed that PfNCR1 is the likely target of MMV006931.

While strong political commitment and robust technical strategies are essential to drive malaria elimination, the readiness of national health systems ultimately determines whether these commitments can be successfully translated into action. Without adequate preparation, gaps in the health system can undermine the transition from malaria burden reduction to elimination policies, reduce the effectiveness of interventions, and jeopardise progress toward achieving zero local transmission of malaria. Despite its critical importance, there is currently no systematic and comprehensive approach for assessing health system readiness for malaria elimination. This paper highlights the consequences of unprepared health systems and the urgent need for standardised, structured, comprehensive readiness assessments that would enable policymakers and programme managers to systematically evaluate health system readiness for malaria elimination at national and subnational levels, identify and address critical gaps, and strengthen the health systems. These efforts will support sustained elimination and achieve WHO-certified malaria elimination.

Background Countries in the Greater Mekong Subregion (GMS) have pledged to eliminate malaria by 2030. Achieving malaria elimination is a complex undertaking that requires a strong and well-functioning health system. Assessing health system readiness comprehensively at both national and sub-national levels is critical, as commitment at the national level does not necessarily translate into adequate readiness at lower administrative levels. To better understand the requirements for implementing malaria elimination strategies at the sub-national level and to identify challenges that could hinder progress toward elimination, a qualitative study was conducted across the GMS. Methods Semi-structured interviews were conducted with 39 key stakeholders, including policymakers (n = 5), health personnel from Ministries of Health (n = 12), managers and field supervisors from malaria implementing partners (n = 16), and representatives from technical agencies and research institutions (n = 6). The data were analysed using reflexive thematic analysis, and the findings were organised according to themes derived from the World Health Organization’s six health system building blocks framework (service delivery, surveillance, elimination workforce, products and commodities, programme financing and leadership and governance). Results Stakeholders observed that sub-national level health systems for malaria elimination required inputs from all six WHO health system building blocks. They noted health system related issues in the current sub-national level malaria elimination programmes of the GMS included service disruptions, delayed implementation of reactive surveillance and response activities, human resource shortages, stock-outs of malaria commodities, and unorganised coordination with relevant sectors at the sub-national level – all of which could hinder the progress of GMS countries towards malaria elimination. Conclusions This study comprehensively evaluated sub-national health system needs and issues regarding implementation of malaria elimination activities in the GMS countries. It highlighted the importance of health system readiness at sub-national levels in translating political commitment into effective action. Furthermore, this study emphasised the need to evaluate the health system readiness comprehensively at sub-national level in order to accelerate the progress towards malaria elimination by 2030.

Summary Plasmodium falciparum causes the majority of severe malaria, and merozoite invasion of erythrocytes is a vulnerable, antibody-accessible step of the blood-stage cycle. PfRipr is an essential component of the PCRCR invasion complex, yet the structural basis for antibody-mediated neutralisation remains unclear. Here, we map inhibitory and non-inhibitory epitopes across PfRipr and show that all potent inhibitors localise to the tail region (EGF6-8). Crystal structures reveal that inhibitory antibodies restrict the flexibility surrounding EGF7. Indeed, EGF7 buried surface area correlates strongly with inhibitory potency, identifying this domain as the principal invasion-inhibitory determinant. Pairwise antibody combinations revealed unexpected synergy, with non-inhibitory mAbs potentiating anti-Rh5 activity. Conditional deletion, sequence replacement or positional swapping of EGF6-8 abolished invasion, demonstrating that both sequence and spatial arrangement are indispensable. These data define EGF7 as a conserved, functionally essential vulnerability and provide a blueprint for rational EGF6-8 immunogen design capable of eliciting P. falciparum strain-transcending protection against blood-stage malaria.

[This corrects the article DOI: 10.3389/fgene.2025.1621920.].

Plasmepsin V (PMV), an essential aspartyl protease, plays a critical role during the asexual blood stage of infection of Plasmodium by enabling the export of parasite proteins into the host red blood cell. This export is vital for parasite survival and pathogenesis, making PMV an attractive target for antimalarial drug development. Peptidomimetic inhibitors designed to mimic the natural substrate of PMV have demonstrated potent parasite-killing activity by blocking protein export. While these compounds have been instrumental in validating PMV as a bona fide antimalarial target, inconsistencies between their biochemical potency and cellular activity have raised questions regarding their precise mechanism of action. In this study, we employed chemoproteomic approaches, including solvent-induced protein precipitation and intact-cell thermal profiling, to demonstrate PMV target engagement by the peptidomimetics. To further support these findings, we generated parasite lines exhibiting reduced sensitivity to peptidomimetics. Through whole-genome sequencing of these parasite lines, a single nucleotide variant within the pmv gene was revealed. This mutation was later validated using reverse genetics, confirming its role in mediating resistance. Together, these data provide strong evidence that the peptidomimetics exert their antimalarial activity by directly targeting PMV. These findings further support the potential of PMV as a validated and promising target for future antimalarial drug development.

Background:Plasmodium vivax poses a major obstacle to malaria elimination because it can lie dormant in the liver for weeks or months before reactivating and causing a relapse of infection. These dormant forms (hypnozoites) cannot be detected using standard diagnostics, but recent P. vivax exposure and by proxy, hypnozoite carriage, can be inferred using antibody-based tests (serological markers). In this study, we examined how genetic variation in P. vivax affects the utility of these antibody markers, and whether redesigned antigens could improve performance. Methods:We analysed global P. vivax genetic data to assess variation in leading serological markers. Based on this, we produced new antigen versions (haplotypes) that better reflect global sequence diversity, compared to the commonly used reference strain (Sal-1). Antibody responses against these new constructs were then tested using samples from well-characterised cohorts in Brazil and Thailand. Antibody levels were assessed in relation to how recently participants had a qPCR-detectable blood-stage P. vivax infection. We compared the ability of the haplotypes and reference constructs to correctly identify individuals infected within the prior 9-months. Findings:Extensive genetic diversity was identified in two P. vivax antigens, DBPII and MSP5. Several antigens had large numbers of circulating haplotypes globally, with the percentage with similar sequence identity to the reference Sal-1 ranging from 0.4% (MSP5) to 99% (S16). Two antigens exhibited strong differences in immunogenicity by region and construct (RBP2a and DBPII). However, for most proteins (5 out of 8), these differences had little impact on the accuracy of identifying recent exposure. In cases where performance was affected (e.g. RBP2a), this could be overcome by adding multiple antigens into the classification model. Interpretation:Even highly diverse antigens can be effective serological exposure markers. Our findings highlight the importance of testing the impact of genetic diversity when designing serological tests and suggest practical strategies, such as using a mix of antigens, to ensure consistent performance across regions.

Background Malaria continues to pose a significant burden in endemic countries, many of which lack access to molecular surveillance. Insights from malaria cases in travellers returning to non-endemic areas can provide valuable data to inform endemic country programmes. To evaluate the potential for novel global insights into malaria, we examined epidemiological and molecular data from imported malaria cases to Australia.Methods We analysed malaria cases reported in Australia from 2012 to 2022 using National Notifiable Disease Surveillance System data. Molecular data on imported malaria cases were obtained from literature searches.Results Between 2012 and 2022, 3204 malaria cases were reported in Australia. Most cases (69%) were male and 44% occurred in young adults aged 20-39 years. Incidence rates initially declined between 2012 and 2015, then increased until 2019. During 2012-2019, the incidence in travellers ranged from 1.34 to 7.71 per 100 000 trips. Cases were primarily acquired in Sub-Saharan Africa (n = 1433; 45%), Oceania (n = 569; 18%) and Southern and Central Asia (n = 367; 12%). The most common countries of acquisition were Papua New Guinea (n = 474) and India (n = 277). Plasmodium falciparum accounted for 58% (1871/3204) of cases and was predominantly acquired in Sub-Saharan Africa, and Plasmodium vivax accounted for 32% (1016/3204), predominantly from Oceania and Asia. Molecular studies of imported malaria cases to Australia identified genetic mutations and deletions associated with drug resistance and false-negative rapid diagnostic test results, and led to the establishment of reference genomes for P. vivax and Plasmodium malariae.Conclusions Our analysis highlights the continuing burden of imported malaria into Australia. Molecular studies have offered valuable insights into drug resistance and diagnostic limitations, and established reference genomes. Integrating molecular data into national surveillance systems could provide important infectious disease intelligence to optimize treatment guidelines for returning travellers and support endemic country surveillance programmes.

The World Health Organization identifies a strong surveillance system for malaria and its mosquito vector as an essential pillar of the malaria elimination agenda. Anopheles salivary antibodies are emerging biomarkers of exposure to mosquito bites that potentially overcome sensitivity and logistical constraints of traditional entomological surveys. Using samples collected by a village health volunteer network in 104 villages in Southeast Myanmar during routine surveillance, the present study employs a Bayesian geostatistical modeling framework, incorporating climatic and environmental variables together with Anopheles salivary antigen serology, to generate spatially continuous predictive maps of Anopheles biting exposure. Our maps quantify fine-scale spatial and temporal heterogeneity in Anopheles salivary antibody seroprevalence (ranging from 9 to 99%) that serves as a proxy of exposure to Anopheles bites and advances current static maps of only Anopheles occurrence. We also developed an innovative framework to perform surveillance of malaria transmission. By incorporating antibodies against the vector and the transmissible form of malaria (sporozoite) in a joint Bayesian geostatistical model, we predict several foci of ongoing transmission. In our study, we demonstrate that antibodies specific for Anopheles salivary and sporozoite antigens are a logistically feasible metric with which to quantify and characterize heterogeneity in exposure to vector bites and malaria transmission. These approaches could readily be scaled up into existing village health volunteer surveillance networks to identify foci of residual malaria transmission, which could be targeted with supplementary interventions to accelerate progress toward elimination.

Objectives:Following the scaling-up of malaria control strategies in Mali, understanding the changes in age-specific prevalence of infection and risk factors associated with remains necessary to determine new priorities to progress toward disease elimination. This study aimed to estimate the risk of clinical malaria using longitudinal data across three different transmission settings in Mali.Methods:Cohort-based longitudinal studies were performed from April 2018 to December 2022. Incidence of malaria was measured through community health center-based passive case detection. Generalized estimation equation model was used to assess risk factors for clinical malaria.Results:A total of 21,453 clinical presentations were reported from 4500 participants, mainly from July to November. Data shows a significant association between malaria episodes, sex, age group, season, and year. Women had lower risk, the risk of clinical episode increased with age up to 14 years then declined, and in both sites, the dry-season risk of clinical episode was significantly lower compared to the rainy season.Conclusion:Determining factors associated with the occurrence of clinical malaria across different ecological settings across the country could help in the development of new strategies aiming to accelerate malaria elimination in an area where malaria transmission remains intense.

ABSTRACTThe complex life cycle of Plasmodium parasites, the eukaryotic pathogens that cause malaria, features three distinct invasive forms tailored specifically to the equally distinct host environment they must navigate and invade for progression of the life cycle. One conserved feature of all these invasive forms is the presence of micronemes, apically oriented secretory organelles involved in egress, motility, adhesion and invasion. Micronemes are tailored to their specific host environment and feature stage specific contents. Here we investigate the role of GPI-anchored micronemal antigen (GAMA), which shows a micronemal localization in all zoite forms of the rodent infecting species Plasmodium berghei. While GAMA is dispensable during asexual blood stages, GAMA knock out parasites are severely defective for invasion of the mosquito midgut, resulting in reduced numbers of oocysts. Once formed, oocysts develop normally, however sporozoites are unable to egress and these sporozoites exhibit defective motility. Epitope-tagging of GAMA revealed tight temporal expression late during sporogony and showed that GAMA is shed during sporozoite gliding motility in a similar manner to circumsporozoite protein. Complementation of P. berghei knock out parasites with full length P. falciparum GAMA partially restored infectivity to mosquitoes, indicating a conservation of function across Plasmodium species. A suite of parasites with GAMA expressed under the promoters of the known ookinete-to-sporozoite stage-specific genes: CTRP, CAP380 and TRAP, further confirmed the involvement of GAMA in midgut infection, motility and infection of the mammalian host and revealed a lethal consequence to overexpression of GAMA during oocyst development. Combined, the research suggest that GAMA plays independent roles in sporozoite motility, egress and invasion, possibly implicating GAMA as a regulator of microneme function.AUTHOR SUMMARYMalaria remains a major source of morbidity and mortality across the globe. Completion of a complex life cycle between vertebrates and mosquitoes is required for the maintenance of parasite populations and the persistence of malaria disease and death. Three invasive forms across the complex lifecycle of the parasite must successfully egress and invade specific cell types within the vertebrate and mosquito hosts to maintain parasite populations and consequently disease and suffering. A conserved feature of all invasive forms are the micronemes, apically oriented secretory organelles which contain proteins required for motility, egress and invasion. Few proteins are expressed in the micronemes of all three invasive forms. One such protein is GPI-anchored micronemal antigen (GAMA). Here we reveal that GAMA is required for the invasion of the mosquito midgut, egress of sporozoites from oocysts and invasion of the vertebrate host. Our finding indicate that while GAMA is essential for sporozoite motility, the defects in oocyst egress and hepatocyte invasion occur independently of the motility defect, implicating the requirement of GAMA in all three processes.

BackgroundSeasonal malaria chemoprevention (SMC) is recommended by the World Health Organization for the sub-Sahel region in sub-Saharan Africa for preventing malaria in children 3 months old to younger than 5 years. Since 2016, the Malian National Malaria Control Program has deployed SMC countrywide during its high malaria transmission season at a rate of 4 monthly cycles annually. The standard SMC regimen includes sulfadoxine-pyrimethamine (SP) plus amodiaquine (AQ). Resistance against SP is suspected to be rising across West Africa; therefore, assessing the effectiveness of an alternative antimalarial drug for SMC is needed to provide a second-line regimen when it is ultimately needed. It is not well understood whether SMC effectively prevents malaria in children aged 5 years or older. ObjectiveThe primary goal of the study is to compare 2 SMC regimens (SP-AQ and dihydroartemisinin-piperaquine [DHA-PQ]) in preventing uncomplicated Plasmodium falciparum malaria in children 3 months to 9 years old. Secondly, we will assess the possible use of DHA-PQ as an alternative SMC drug in areas where resistance to SP or AQ may increase following intensive use. MethodsThe study design is a 3-arm cluster-randomized design comparing the SP-AQ and DHA-PQ arms in 2 age groups (younger than 5 years and 5-9 years) and a control group for children aged 5-9 years. Standard SMC (SP-AQ) for children younger than 5 years was provided to the control arm, while SMC with SP-AQ was delivered to children aged 3 months to 9 years (arm 2), and SMC with DHA-PQ will be implemented in study arm 3 for children up to 9 years of age. The study was performed in Mali’s Koulikoro District, a rural area in southwest Mali with historically high malaria transmission rates. The study’s primary outcome is P falciparum incidence for 2 SMC regimens in children up to 9 years of age. Should DHA-PQ provide an acceptable alternative to SP-AQ, a plausible second-line prevention option would be available in the event of SP resistance or drug supply shortages. A significant byproduct of this effort included bolstering district health information systems for rapid identification of severe malaria cases. ResultsThe study began on July 1, 2019. Through November 2022, a total of 4556 children 3 months old to younger than 5 years were enrolled. Data collection ended in spring 2023, and the findings are expected to be published later in early 2024. ConclusionsRoutine evaluation of antimalarial drugs is needed to establish appropriate SMC age targets. The study goals here may impact public health policy and provide alternative therapies in the event of drug shortages or resistance. Trial RegistrationClinicalTrials.gov NCT04149106, https://clinicaltrials.gov/ct2/show/NCT04149106 International Registered Report Identifier (IRRID)DERR1-10.2196/51660

With resistance to most antimalarials increasing, it is imperative that new drugs are developed. We previously identified an aryl acetamide compound, MMV006833 (M-833), that inhibited the ring-stage development of newly invaded merozoites. Here, we select parasites resistant to M-833 and identify mutations in the START lipid transfer protein (PF3D7_0104200, PfSTART1). Introducing PfSTART1 mutations into wildtype parasites reproduces resistance to M-833 as well as to more potent analogues. PfSTART1 binding to the analogues is validated using organic solvent-based Proteome Integral Solubility Alteration (Solvent PISA) assays. Imaging of invading merozoites shows the inhibitors prevent the development of ring-stage parasites potentially by inhibiting the expansion of the encasing parasitophorous vacuole membrane. The PfSTART1-targeting compounds also block transmission to mosquitoes and with multiple stages of the parasite’s lifecycle being affected, PfSTART1 represents a drug target with a new mechanism of action.