Molecular epidemiology and genetic diversity of disappearing Plasmodium vivax in southern Thailand.

The evolution of genetic diversity and population structure of Plasmodium vivax as malaria elimination approaches remains unclear. This study analyzed the genetic variation and molecular epidemiology of P. vivax from Yala Province in southern Thailand, an area in the pre-elimination phase.

Potent AMA1-specific human monoclonal antibody against Plasmodium vivax Pre-erythrocytic and Blood Stages.

New therapeutics are necessary for preventing Plasmodium vivax malaria due to easy transmissibility and dormancy in the liver that increases the clinical burden due to recurrent relapse. In this manuscript we characterize 12 Pv Apical Membrane Antigen 1 (PvAMA1) specific human monoclonal antibodies from Peripheral Blood Mononuclear Cells of a Pv-exposed individual. PvAMA1 is essential for sporozoite and merozoite invasion, making it a unique therapeutic target.

Declining genetic polymorphism of the C-terminus Merozoite Surface Protein-1 amidst increased Plasmodium knowlesi transmission in Thailand.

Background: Recent reports from Thailand reveal a substantial surge in Plasmodium knowlesi cases over the past decades, with a more than eightfold increase in incidence by 2023 compared to 2018. This study investigates temporal changes in genetic polymorphism associated with the escalating transmission of P. knowlesi malaria in Thailand over time using the prominent vaccine candidate, pkmsp1 as a marker.

Human-to-Anopheles dirus mosquito transmission of the anthropozoonotic malaria parasite, Plasmodium knowlesi.

Background: Plasmodium knowlesi, identified as the fifth human malaria parasite, has rapidly spread across various Southeast Asian countries, yet uncertainties persist regarding its human-mosquito-human transmission. Therefore, this study aims to explore the transmission potential of P. knowlesi from human blood to mosquitoes.

Optimizing Transfection Efficiency of Spermine Polar Head Cholesterol-Based Cationic Lipids with Amino Acid Linker.

In this work, a series of spermine polar head cholesterol-based cationic lipids with various amino acid spacers were synthesized and evaluated as non-viral gene delivery systems. The physicochemical properties of the resulting lipoplexes, formed from these lipids and DOPE, were assessed, including zeta-potential, DNA binding and DNA protection from serum. Transfection efficiency and cytotoxicity were examined under serum-free and 10-40 % serum-containing conditions.

Immunogenicity and transmission-blocking potential of quiescin sulfhydryl oxidase in .

Background: Transmission-blocking vaccines (TBVs) can effectively prevent the community's spread of malaria by targeting the antigens of mosquito sexual stage parasites. At present, only a few candidate antigens have demonstrated transmission-blocking activity (TBA) potential in . Quiescin-sulfhydryl oxidase (QSOX) is a sexual stage protein in the rodent malaria parasite and is associated with a critical role in protein folding by introducing disulfides into unfolded reduced proteins.

Demographic and socioeconomic obstacles to access to malaria services for Myanmar migrants in Thailand.

Background: Typically mobile and vulnerable, migrants face significant barriers to access to routine malaria prevention, diagnostics and treatment, which leads to unchecked malaria transmission, particularly in border regions with a high population displacement. This study aimed to investigate the demographic and socioeconomic obstacles to access to malaria services among Myanmar migrants residing in the Thailand-Myanmar border areas.

Methods: A cross-sectional study was conducted in early 2024 across three districts near the Thailand-Myanmar border.

Declining Genetic Polymorphisms of the C-terminus Merozoite Surface Protein-1 Amidst Increased Transmission in Thailand.

Recent reports from Thailand reveal a substantial surge in cases over the past decade, with a more than eightfold increase in incidence by 2023 compared to 2018. This study investigates temporal changes in genetic polymorphism associated with the escalating transmission of malaria in Thailand over the past two decades. Twenty-five samples collected in 2018-2023 were sequenced for the 42-kDa region of and compared with 24 samples collected in 2000-2009, focusing on nucleotide diversity, natural selection, recombination rate, and population differentiation.

Plasmodium vivax populations in the western Greater Mekong Subregion evaluated using a genetic barcode.

An improved understanding of the Plasmodium vivax populations in the Great Mekong Subregion (GMS) is needed to monitor the progress of malaria elimination. This study aimed to use a P. vivax single nucleotide polymorphism (SNP) barcode to evaluate the population dynamics and explore the gene flow among P.

Effectiveness, Safety, and Acceptability of Primaquine Mass Drug Administration in Low-Endemicity Areas in Southern Thailand: Proof-of-Concept Study.

Background: A challenge in achieving the malaria-elimination target in the Greater Mekong Subregion, including Thailand, is the predominance of Plasmodium vivax malaria, which has shown extreme resilience to control measures.

Objective: This proof-of-concept study aimed to provide evidence for implementing primaquine mass drug administration (pMDA) as a strategy for P. vivax elimination in low-endemicity settings.

Evaluation of transmission-blocking potential of PvPSOP25 using transgenic murine malaria parasite and clinical isolates.

Background: Malaria transmission-blocking vaccines (TBVs) aim to inhibit malaria parasite development in mosquitoes and prevent further transmission to the human host. The putative-secreted ookinete protein 25 (PSOP25), highly conserved in Plasmodium spp., is a promising TBV target.

Ownership and use of insecticide-treated nets in Myanmar: insights from a nationally representative demographic and health survey.

Background: Malaria poses a substantial public health threat in Myanmar, indicating the need for rigorous efforts to achieve elimination of the disease nationwide by 2030. The use of insecticide-treated nets (ITNs) forms part of a pivotal strategy for preventing transmission. This study explored the ownership and use of ITNs in Myanmar and identified factors associated with non-use of ITNs.

Potent AMA1-specific human monoclonal antibody against P. vivax Pre-erythrocytic and Blood Stages.

New therapeutics are necessary for preventing Plasmodium vivax malaria due to easy transmissibility and dormancy in the liver that increases the clinical burden due to recurrent relapse. We isolated 12 Pv Apical Membrane Antigen 1 (PvAMA1) specific human monoclonal antibodies from Peripheral Blood Mononuclear Cells of a Pv exposed individual. PvAMA1 is essential for sporozoite and merozoite invasion, making it a unique therapeutic target.

Azithromycin disrupts apicoplast biogenesis in replicating and dormant liver stages of the relapsing malaria parasites Plasmodium vivax and Plasmodium cynomolgi.

The control and elimination of malaria caused by Plasmodium vivax is hampered by the threat of relapsed infection resulting from the activation of dormant hepatic hypnozoites. Currently, only the 8-aminoquinolines, primaquine and tafenoquine, have been approved for the elimination of hypnozoites, although their use is hampered by potential toxicity. Therefore, an alternative radical curative drug that safely eliminates hypnozoites is a pressing need.

A Pvs25 mRNA vaccine induces complete and durable transmission-blocking immunity to Plasmodium vivax.

Plasmodium vivax (P. vivax) is the major malaria parasite outside of Africa and no vaccine is available against it. A vaccine that interrupts parasite transmission (transmission-blocking vaccine, TBV) is considered highly desirable to reduce the spread of P.

In Vitro Tracking of Sporozoites via Fluorescence Imaging and MRI Using Multifunctional Micelles.

Early detection could increase the treatment efficiency and prevent the recurrence of malaria disease. To track and detect malarial sporozoites, novel drug delivery systems have been explored for their ability to target these parasites specifically. This study investigates the potential of micelles to track by targeting the hexose transporter using glucose-based interactions.

Host kinase regulation of dormant and replicating liver stages.

Upon transmission to the liver, parasites form replicating schizonts, which continue to initiate blood-stage infection, or dormant hypnozoites that reactivate weeks to months after initial infection. phenotypes in the field vary significantly, including the ratio of schizonts to hypnozoites formed and the frequency and timing of relapse. Evidence suggests that both parasite genetics and environmental factors underly this heterogeneity.

Naturally Acquired Transmission-Blocking Immunity Against Different Strains of Plasmodium vivax in a Malaria-Endemic Area in Thailand.

Background: Human immunity triggered by natural malaria infections impedes parasite transmission from humans to mosquitoes, leading to interest in transmission-blocking vaccines. However, immunity characteristics, especially strain specificity, remain largely unexplored. We investigated naturally acquired transmission-blocking immunity (TBI) against Plasmodium vivax, a major malaria parasite.

Interventions for promoting patients' adherence to 14-day primaquine treatment in a highly malaria-endemic township in Myanmar: a qualitative study among key stakeholders.

Background: Plasmodium vivax malaria is considered a major threat to malaria eradication. The radical cure for P. vivax malaria normally requires a 14-day administration of primaquine (PQ) to clear hypnozoites.

Interventions for promoting patients' adherence to 14-day primaquine treatment in a highly malaria-endemic township in Myanmar: A qualitative study among key stakeholders.

Background: malaria is considered a major threat to malaria eradication. The radical cure for malaria normally requires a 14-day administration of primaquine (PQ) to clear hypnozoites. However, maintaining adherence to PQ treatment is a significant challenge, particularly in malaria-endemic rural areas.

Identification of potent and selective N-myristoyltransferase inhibitors of Plasmodium vivax liver stage hypnozoites and schizonts.

Drugs targeting multiple stages of the Plasmodium vivax life cycle are needed to reduce the health and economic burdens caused by malaria worldwide. N-myristoyltransferase (NMT) is an essential eukaryotic enzyme and a validated drug target for combating malaria. However, previous PvNMT inhibitors have failed due to their low selectivity over human NMTs.

Antennal morphology and sensilla ultrastructure of the malaria vectors, Anopheles maculatus and An. sawadwongporni (Diptera: Culicidae).

Mosquitoes rely mainly on the olfactory system to track hosts. Sensilla contain olfactory neuron receptors that perceive different kinds of odorants and transfer crucial information regarding the surrounding environment. Anopheles maculatus and An.

High-Throughput Antibody Profiling Identifies Targets of Protective Immunity against Malaria in Thailand.

Malaria poses a significant global health challenge, resulting in approximately 600,000 deaths each year. Individuals living in regions with endemic malaria have the potential to develop partial immunity, thanks in part to the presence of anti-plasmodium antibodies. As efforts are made to optimize and implement strategies to reduce malaria transmission and ultimately eliminate the disease, it is crucial to understand how these interventions impact naturally acquired protective immunity.

Activity of Ivermectin and Its Metabolites against Asexual Blood Stage Plasmodium falciparum and Its Interactions with Antimalarial Drugs.

Ivermectin is an endectocide used widely to treat a variety of internal and external parasites. Field trials of ivermectin mass drug administration for malaria transmission control have demonstrated a reduction of mosquito survival and human malaria incidence. Ivermectin will mostly be deployed together with artemisinin-based combination therapies (ACT), the first-line treatment of falciparum malaria.