As many countries implement different programs aimed at eliminating malaria, attention should be given to asymptomatic carriers that may interrupt the progress. This was a community-based cross-sectional study conducted in Tanzania from December 2022 to July 2023 within 4 villages from each of the 3 regions, Geita and Kigoma, which are high malaria transmission, and Arusha, which is low transmission. Malaria was diagnosed in asymptomatic individuals aged 1 year and older using the malaria rapid diagnostic test and light microscope. A total of 2,365 of 3,489 (67.9%) participants were enrolled from high-transmission villages. The overall prevalence was 25.5% and 15.8% by malaria rapid diagnostic test and light microscope, respectively. Using the respective tools, the prevalence was significantly higher at 35.6% (confidence interval (CI)=23.6–49.9) and 23.1% (CI=16.2–35.1) in the high-transmission regions (Geita and Kigoma) compared with 2.9% (CI=1.1–3.5) and 1.1% (CI=0.7–1.8) in the low-transmission region (Arusha). Children younger than 15 years and males accounted for the greatest proportion of infections. In the study area, the prevalence of asymptomatic cases was higher than that of reported symptomatic cases in health facilities. We hypothesize that these parasite reservoirs may contribute to the persistence of malaria in the country. Therefore, to achieve comprehensive malaria control in the country, the surveillance and screening of asymptomatic malaria cases are vital.

This study investigates the antimalarial potential of extracts and compounds from various plants used in traditional Korean medicine, in response to the increasing resistance of Plasmodium falciparum to standard treatments such as chloroquine and artemisinin. The antimalarial activity screening was conducted on 151 extracts, identifying the top seven candidates, including Geranium thunbergii (50% ethanol and 100% methanol extract), Reynoutria japonica, Amomum villosum (hot water and 50% ethanol extract), Cinnamomum zeylanicum, and Platycodon grandiflorum. Among these, G. thunbergii was identified as the top priority for further analysis due to its high antimalarial activity and high yield of bioactive compounds. The plant extracts were fractionated using ethyl acetate, chloroform, and hot water, and their efficacy against P. falciparum was evaluated through IC₅₀ determination and microscopic analysis. The compounds evaluated included ellagic acid, gallic acid, afzelin, quercetin, and protocatechuic acid. Among the tested compounds, ellagic acid showed the most potent antimalarial activity with an IC₅₀ of 1.60 ± 0.09 µM, followed by gallic acid (39.43 ± 1.48 µM) and afzelin (52.77 ± 1.84 µM). In contrast, quercetin (116.8 ± 3.78 µM) and protocatechuic acid (1.23 ± 0.02 mM) exhibited minimal antimalarial effects. Giemsa staining was employed to visualize parasite morphology and confirmed that ellagic acid is effective in inhibiting growth at the late trophozoite stage. These findings suggest that ellagic acid could serve as a promising lead compound for developing a novel antimalarial agent. This study highlights the importance of exploring plant-based compounds as alternative strategies against drug-resistant malaria. Further investigation into the mechanisms underlying the antimalarial activity of these compounds is necessary to fully validate their therapeutic potential.

The emergence and spread of Plasmodium falciparum resistance to malaria drugs pose a major threat to malaria control efforts. This study assessed the prevalence of molecular markers associated with resistance to key antimalarials in P. falciparum clinical isolates from Mzuzu and Lilongwe in Malawi. These two regions have high human mobility and are strategically located near the border with Zambia and Tanzania, respectively. A total of 1,582 blood samples were collected from individuals who visited hospitals for diagnosis between December 2020 and June 2021. P. falciparum infections were confirmed using nested and quantitative PCR, and drug resistance marker genes (pfmdr1, pfcrt, pfk13, pfatp6, pfdhfr, and pfdhps) were sequenced by Sanger sequencing. No resistance-associated mutations were detected in pfk13 and pfcrt genes, supporting continued susceptibility to artemisinin derivatives and chloroquine (CQ). However, the pfmdr1-NFD haplotype, linked to reduced lumefantrine (LUM) susceptibility, was present in 159/371 (42.9%) isolates. Notably, the quadruple pfdhfr-pfdhps mutant haplotype (AIRNVI-SGEAA), associated with high-level sulfadoxine-pyrimethamine (SP) resistance, was found 287/328 (87.5%) of isolates. These findings highlight the ongoing risk of declining efficacy of LUM partner drugs in artemisinin-based combination therapies (ACT) and reduced SP effectiveness for intermittent preventive treatment in pregnancy (IPTp). The absence of pfcrt mutations, together with the presence of wild type pfmdr1 alleles lacking CQ-related mutation, suggests the re-emergence of CQ-sensitive parasites. Continuous molecular surveillance, alongside clinical efficacy studies, is essential to inform treatment policies and prevent the spread of drug-resistant malaria in Malawi.

Glucose acquisition is essential for the long-term survival of adult Clonorchis sinensis within the host bile duct. Although several glucose transporter-related proteins have been identified in C. sinensis, the molecular and functional properties of facilitative glucose transport proteins, including the protein designated as glucose transporter protein 5 (CsGTP5) in this study, have not been characterized. In this study, CsGTP5 was cloned from adult C. sinensis and functionally analyzed using the Xenopus laevis oocyte expression system. The CsGTP5 open reading frame comprised 1,575 bp and encoded a 524-amino-acid protein with 12 predicted transmembrane domains, consistent with the topology of facilitative glucose transporter-like proteins. CsGTP5-expressing oocytes showed significantly increased uptake of [3 H] deoxy-D-glucose compared with water-injected control oocytes, whereas no significant uptake was observed for other tested substrates, including arginine, α-ketoglutarate, p-aminohippurate, taurocholate, and tetraethylammonium. CsGTP5-mediated [3 H] deoxy-D-glucose uptake increased in a time-dependent manner and was not affected by replacement of extracellular Na+ with Li+ or choline, indicating sodium-independent transport. Uptake was saturable, with an apparent Km of 4.0 mM and a Vmax of 300.0 pmol/oocyte/h. Competition assays showed that deoxy-D-glucose and glucose strongly inhibited CsGTP5-mediated uptake, whereas other monosaccharides had little effect. Molecular docking analysis further supported the predicted glucose-recognition capacity of CsGTP5. These findings demonstrate that CsGTP5 mediates sodium-independent deoxy-D-glucose uptake in a heterologous oocyte expression system and provide a basis for further investigation of its physiological role in C. sinensis.