Acta Tropica

BackgroundMalaria control is increasingly challenged by the urban-adapted vector Anopheles stephensi, yet molecular and cellular tools for this species remain scarce, restricting functional genomic studies and the development of genetic control strategies. To help address this gap, we established a new embryo-derived Anopheles stephensi cell line. ResultsWe generated and characterised a novel embryo-derived Anopheles stephensi (SDA-500) cell line capable of sustained growth in vitro. Species identity was confirmed by mitochondrial COI barcoding, and karyotypic analysis revealed a diploid chromosome complement with the presence of a Y chromosome, confirming that at least some cells are of male origin. Transfection conditions were optimized, with TransIT-PRO showing higher efficiency than Lipofectamine-based reagents. Using a dual-luciferase reporter assay, of several promoters tested the Anopheles gambiae polyubiquitin promoter exhibited the strongest and most consistent transcriptional activity in SDA-500 cells. ConclusionsThe SDA-500 cell line provides a stable and genetically validated in vitro platform that supports efficient transgene expression. This resource provides a useful system for functional genomics and molecular manipulation in Anopheles stephensi and is expected to facilitate studies of mosquito biology and contribute to the development of novel malaria control strategies.

BackgroundResistance of the arbovirus vector Aedes albopictus to pyrethroid insecticides is an emerging threat to vector control programs in Europe. Three knock-down resistance (Kdr) mutations affecting the voltage-gated sodium channels targeted by pyrethroids are known to confer resistance: V1016G, I1532T and F1534C. As these Kdr mutations are actively circulating in Europe, their monitoring is crucial for resistance surveillance programs. However, current Kdr genotyping methods are labor-intensive and costly, limiting their applicability for large-scale high-throughput surveillance. MethodologyNovel digital droplet PCR (ddPCR) TaqMan assays were developed, allowing the quantification of these Kdr mutations from pooled mosquito samples from field populations. The specificity of these assays was validated by using mosquitoes of known genotypes together with synthetic DNA constructs carrying haplotype combinations previously unseen in the field. The assays accuracy was assessed by comparing Kdr frequencies measured from pooled mosquitoes to those derived from individual genotypes. These assays were then used in a pilot surveillance study in mainland France, integrating deltamethrin bioassays, pooled Kdr mutation tracking and vector control interventions data. FindingsThe developed ddPCR assays demonstrated high accuracy and specificity, with matching Kdr mutation frequencies between pooled samples and individual genotyping. The pilot surveillance study confirmed the low prevalence of Kdr V1016G and I1532T mutations in most French populations, though some populations exhibited a moderate decrease in susceptibility to deltamethrin. Deltamethrin spraying intensity was weakly correlated with Kdr I1532T mutation frequency while no correlation was observed with deltamethrin susceptibility, suggesting that insecticide selective pressure from curative vector control activities is at most a minor driver of resistance. ConclusionThese novel ddPCR assays provide a simple, cost-effective and high-throughput method for quantifying the frequency of Kdr mutations in Ae. albopictus populations. Their implementation in routine country-wide surveillance programs will enhance the detection of emerging resistance, and inform vector control strategies, preventing arboviral disease transmission. Author summaryAedes albopictus, the Asian tiger mosquito, is an emerging global threat due to its ability to transmit the dengue, chikungunya and Zika viruses among others. Recurrent use of insecticides to prevent infections selects resistant mosquitoes. Kdr (knock-down resistance) mutations confer resistance to pyrethroid insecticides, like deltamethrin. In order to track the arrival of these mutations in a population, individual PCR tests are routinely used, which is very inefficient and costly. The digital droplet PCR tests presented in this study can instead be performed on pools of mosquitoes from the field, greatly increasing the output while reducing the costs. This makes them ideal for use in the surveillance of these mutations in field populations. We first confirmed that the tests are as efficient in pools as they are on single mosquitoes, then we applied these tests in a pilot study on French field mosquitoes to demonstrate their applicability for use in surveillance. Finally, we explored the link between deltamethrin sprayings, bioassay mortality and Kdr mutations frequency, which is non-existent. This means the current management of mosquito populations via insecticide use is sensible. We believe these tests have a place in streamlining the future surveillance programs of these mutations in the field.

Ivermectin is an important broad-spectrum anthelmintic used to treat nematode parasites including gastro-intestinal infections of humans and animals. The mode of action for Ivermectin is understood to involve activation of inhibitory glutamate-gated chloride channels (GluCls). Ivermectin has also been reported to inhibit the release of extracellular vesicles (EVs). We found that EVs are released from the whole intestine of the gastro-intestinal parasite, Ascaris suum. Proteomic analysis identified 1,574 proteins within these intestinal EVs, including 96 nematode proteins with putative immune-associated functions based on homology to proteins involved in host immune processes and 130 proteins with predicted digestive functions. Comparative analysis following ivermectin exposure revealed 38 differentially abundant proteins that included the putative immune-related proteins: transthyretin-like proteins, a small heat-shock antigen, a phospholipase A2, and the NF-{kappa}B subunit p105. Thus, ivermectin modulated the potential immune-related cargo of intestinal EVs. The ivermectin inhibition of intestinal EV release was concentration-dependent with an IC50 of 64 nM. We also identified the expression of GluCl subunit receptor genes in the Ascaris intestine. The potent inhibitory effect of ivermectin on the release of these EVs from the nematode intestine and the expression of GluCl channel subunits sheds further light on the site and mechanisms of action of this important anthelmintic.

Monogenean ectoparasites, particularly Neobenedenia species, cause severe economic losses in mariculture. Here, ectoparasites isolated from cultured hybrid groupers (Epinephelus fuscoguttatus[female] x E. lanceolatus[male]) were confirmed as Neobenedenia melleni based on ITS1 phylogeny. In vivo screening of six structurally diverse compounds identified compound D (CAS No. 206111-37-7), a 5,6-dihydropyridine derivative, as the most effective antiparasitic agent, achieving 76.54% efficacy at 0.5 mg/L in a 90 min bath treatment. Dose-response assays demonstrated that 0.7 mg/L compound D achieved 95.23% antiparasitic efficacy without causing evident tissue damage or cytotoxicity to GF-1 cells. Ultrastructural observation by scanning electron microscopy revealed marked tegumental alterations, including deep fissures and extensive surface folding, in treated parasites. Molecular docking against ten candidate proteins identified {beta}-tubulin as the most favorable docking target, with a binding energy of -6.53 kcal/mol and three hydrogen-bond interactions, suggesting that {beta}-tubulin may be involved in the antiparasitic activity of compound D. Overall, these findings highlight compound D as a promising lead candidate for short-bath therapy against N. melleni and suggest that cytoskeletal disruption through {beta}-tubulin interaction represents a plausible mechanism of action.

IntroductionChanges in vector control strategies alter the selection pressures exerted on natural populations of Anopheles gambiae s.l. and may influence the dynamics of insecticide resistance mechanisms. However, the consequences of discontinuing indoor residual spraying (IRS) campaigns on the evolution of Ace-1-mediated resistance remain poorly documented under natural conditions. This study aimed to assess the spatiotemporal evolution of resistance to pirimiphos-methyl following the cessation of IRS and to investigate evidence consistent with the existence of a biological cost associated with Ace-1-mediated resistance. MethodsNatural populations of An. gambiae s.l. were collected between 2017 and 2023 in three districts in Burkina Faso that had undergone IRS campaigns (Kampti, Solenzo, and Kongoussi). Susceptibility tests with pirimiphos-methyl (0.25%) were conducted out following WHO protocols, and a subsample of exposed mosquitoes was genotyped to detect the Ace-1 G119S mutation. Spatiotemporal trends in mortality, allele frequencies and genotypes were analyzed according to the pre-IRS, IRS, and post-IRS periods. The association between the Ace-1 genotype and survival following exposure to pirimiphos-methyl was assessed using logistic regression, while the concordance between phenotypic and molecular indicators of resistance was examined using Spearmans correlation. ResultsThe susceptibility of An. gambiae s.l. populations to pirimiphos-methyl was gradually restored after the discontinuation of IRS at all sites. At the same time, the frequencies of the Ace-1 119S resistance allele declined sharply, particularly in Kampti and Solenzo, while they remained low in Kongoussi throughout the study period. Mosquitoes carrying resistant genotypes had a significantly higher probability of survival after exposure to pirimiphos-methyl than susceptible homozygotes, with resistant homozygotes (RR) exhibiting the greatest survival advantage (OR = 27.62; 95% CI: 6.91-110.45; p < 0.001). A significant negative correlation was observed between the frequency of the Ace-1 119S allele and phenotypic mortality ({rho} = -0.48; p = 0.033), indicating a concordance between the two indicators of resistance. The progressive decline in allele frequencies, the decreasing prevalence of resistant genotypes, and the concomitant restoration of susceptibility are field observations consistent with the existence of biological costs associated with Ace-1-mediated resistance. ConclusionThis study provides field evidence consistent with the existence of biological costs associated with Ace-1-mediated resistance in natural populations of An. gambiae s.l. These results underscore the value of an adaptive resistance management strategy based on alternating selection pressures and could guide future vector control strategies, particularly if indoor residual spraying campaigns or other interventions relying on organophosphates were reintroduced.

Short-chain dehydrogenases/reductases (SDRs) constitute a large enzyme superfamily involved in endogenous metabolism and xenobiotic biotransformation. In the parasitic nematode Haemonchus contortus, SDRs may catalyze the carbonyl reduction of a benzimidazole anthelmintic flubendazole (FLU), whose increased reduction is associated with FLU resistance. This study thus investigated the constitutive expression of SDRs and their inducibility by FLU in drug-susceptible and benzimidazole-resistant strains of H. contortus. The expression of 23 sdr genes was analyzed by quantitative PCR, while targeted proteomic assays enabled the quantification of 15 SDR proteins. In adult nematodes, pronounced sex-dependent differences were detected at both transcript and protein levels. Resistance-associated alterations were less pronounced and were observed predominantly in males, with SDR9, SDR12, SDR15, and SDR20 displaying increased protein abundances in the resistant strain. Exposure to FLU induced only minimal transcriptional responses in juvenile stages, whereas adult nematodes exhibited marked sex- and strain-specific responses in the expression of SDRs. The strongest transcriptional effects were detected in resistant males, while significant protein-level changes following FLU treatment were observed exclusively in adults of the drug-susceptible strain. Notably, SDR9 and SDR20 combined resistance-associated expression patterns with responsiveness to FLU exposure. Taking together, the first targeted proteomic characterization of SDRs in H. contortus revealed several SDR isozymes with constitutive overexpression in resistant nematodes and/or inducibility by FLU, suggesting a potential role in adaptation to anthelmintic exposure.

Parasitic infections pose multifaceted threats to farmed fish, extending beyond direct pathogenicity to facilitate infections of bacteria, viruses, and microparasites. This synergistic interaction often leads to co-infections that significantly exacerbate disease outbreaks and mortality, presenting a severe challenge to aquaculture sustainability. Recently, a novel trypanosomiasis caused by the Trypanosoma carassii spectrum has emerged in cage-cultured Larimichthys crocea along the southeast coast of China, resulting in widespread prevalence and high mortality rates. Although this pathogen is hypothesized to originate from freshwater fish, its transmission route in marine environments has remained elusive. In this study, we investigated potential vectors and intermediate hosts of T. carassii spectrum, including leeches and monogenean in natural marine settings, and simulated transmission pathways using an established laboratory model involving T. carassii spectrum, Micropterus salmoides and the leech Poecilobdella manillensis. First, our field surveys in the coast of Ningde, Fujian Province, revealed a nearly 100% co-infection rate of T. carassii spectrum and the monogenean Neobenedenia girellae in diseased juvenile L. crocea. PCR analysis detected T. carassii spectrum traces in some N. girellae specimens, and subsequent experiments confirmed that N. girellae ingests the trypanosome while feeding on host blood. Furthermore, bacterial co-pathogens, such as Vibrio harveyi, were also detected within N. girellae. We also document two fatal leech infestations: Zeylanicobdella arugamensis in hybrid groupers (Epinephelus moara [female] X Epinephelus lanceolatus [male]) in Zhangpu, and Limnotrachelobdella okae in E. lanceolatus and E. fuscoguttatus in Raoping. These leeches tested negative for trypanosomes but carried pathogenic bacteria that co-infected the host fish; nonetheless, they are established vectors for trypanosome transmission. In a laboratory cohabitation model simulating T. carassii spectrum transmission, infected M. salmoides were housed with healthy conspecifics under three conditions: Group A (with the leech P. manillensis), Group B (no leeches), and Group C (no leeches, with physical separation between infected and healthy fish). After 14 days, blood smear microscopy and PCR analysis revealed infection rates in healthy fish of 58.33% in Group A, 40.00% in Group B, and 0% in Group C. Conclusively, T. carassii spectrum can be transmitted via leeches (with higher efficiency) and may also spread through direct contact under high-density aquaculture conditions, whereas N. girellae may act as an incidental vector, further research is warranted to clarify transmission dynamics in natural marine ecosystems. Additionally, our findings highlight the role of ectoparasites, including N. girellae and leeches, as potential reservoirs and vectors for bacterial pathogens of fish. In high-density intensive aquaculture, this vectorial capacity transforms parasites from primary pathogens into key drivers of polymicrobial disease outbreaks.

Japanese encephalitis virus (JEV) is an emerging mosquito-borne flavivirus with potential for geographic expansion, yet the risk of establishment in North America remains poorly characterized. We assessed vector competence of three North American Culex species (Cx. pipiens, Cx. quinquefasciatus, and Cx. tarsalis) for the JEV Nakayama strain, isolated from human brain in 1934 in Japan, across five constant temperatures (15, 20, 25, 30, and 33{degrees}C) at 4, 7, and 14 days post-feeding, quantifying infection, dissemination, and transmission rates. Vector competence was low but non-zero across all species. Cx. pipiens showed higher infection rates than the other species, whereas Cx. quinquefasciatus and Cx. tarsalis were minimally susceptible under these experimental conditions. Temperature had limited effects on infection and no detectable effects on dissemination or transmission. These findings suggest limited transmission potential of JEV Nakayama in North America, with Cx. pipiens as a relatively permissive vector.

Background: Snakebite envenoming is a major cause of preventable death and disability in the Brazilian Amazon, where long distances, sparse roads, and dependence on river transport delay access to antivenom. We developed location-allocation models to identify community health centers that could strategically expand access to antivenom in Amazonas State, Brazil. Methodology/Principal Findings: We conducted an ecological geospatial study using a 2025 WorldPop population surface, locations of existing and candidate health facilities, and a multimodal road-and-river transportation network derived from OpenStreetMap and HydroSHEDS. Population demand was represented by 7,065 populated centroids, including 1,586 within Indigenous territories. We applied a maximize-coverage algorithm with a six-hour travel-time threshold. Two models were developed: one for Amazonas excluding Manaus and one for populations living in Indigenous territories. Both models began with 77 facilities already providing antivenom and progressively added candidate community health centers until coverage gains plateaued. The plateau occurred at 110 facilities, corresponding to 33 additional centers. In the model excluding Manaus, this configuration covered 1,118,831 people, or 75.11% of the target population; 87.61% of those covered could reach care within three hours. In Indigenous territories, coverage increased from 50.55% to 69.50%, reaching 50,434 people, of whom 81.39% were within three hours of care. Validation used 3,595 snakebite notifications from the 30 highest-burden municipalities in the Brazilian Notifiable Diseases Information System during 2023-2025. The median proportion reaching care within six hours was 40.81% in observed data and 72.17% in model estimates. Conclusions/Significance: Strategically equipping 33 additional existing community health centers could substantially expand timely access to antivenom, particularly in rural and Indigenous areas. Location-allocation modeling that incorporates river transportation can support evidence-based decentralization of time-sensitive health services in geographically complex settings.

Catenulids are free-living flatworms, common in eutrophic freshwaters such as ponds, ditches, or peatbogs, with most of the diversity described from tropical regions to date. Although the majority of the species have been described from warmer climates, most molecular studies have been done on specimens from temperate zones in Europe. We addressed this gap by sampling for exotic species in localities available in a temperate climate. In this study, we investigated catenulid diversity in the greenhouses at the University of Warsaw Botanic Garden and recorded two species known only from tropical areas (Stenostomum paraguayense and Suomina evelinae) and one exotic species recorded previously from a greenhouse in Poland (Stenostomum corderoi). Additionally, in the latter species, we provide evidence for environmentally induced coloration of sensory pits, which has not been reported thus far. We placed the collected species on a phylogeny using barcoding of 18S, 28S, and COI genes and retrieved paraphyly of the family Catenulidae, with S. evelinae forming a sister group to the genus Paracatenula, and hence we propose a revision of its systematic position. In total, we recorded six species, including three with a wide cosmopolitan distribution (C. turgida, S. grande and S. tuberculosum), and provided sequences for five of them, three of which had no previous molecular records (S. paraguayense, S. evelinae and S. corderoi). Thus, we confirm that greenhouses represent an important source of exotic species for taxonomic work on microscopic invertebrates.

Background Madagascar has one of the highest burdens of schistosomiasis globally, yet epidemiological evidence from the South-east of the country remains limited. Existing surveillance estimates suggest relatively low prevalence in this region. This contrasts with the region's environmental suitability for transmission and its population's high occupational risk through rice farming. Methods A cross-sectional exploratory study was conducted across 13 villages around the Manombo Special Reserve, Farafangana District, between May and July 2025. Participants were surveyed for geographic, environmental and behavioural risk factors for schistosomiasis infection. Infection was diagnosed by Kato-Katz stool microscopy. Multivariable mixed-effects logistic and linear regression, with village as a random intercept, estimated associations with infection and intensity respectively, adjusting for the water catchment area of household water sources, sex, age group, recent praziquantel treatment and village-level open defecation rate. Results 227 participants were included. Overall S. mansoni prevalence was 53.3% (95% CI 46.8-59.8%); median infection intensity was 96 (IQR 48-288) eggs per gram of stool among those infected. Surface water contact was near-universal (97.3%). Prevalence varied markedly between neighbouring villages. No demographic, behavioural, or WASH variable was independently associated with infection. The water catchment area of household water sources was the primary predictor of infection. Conclusions Prevalence substantially exceeded current surveillance estimates, suggesting this population is underserved by existing control programmes. Water catchment area was the dominant determinant of transmission heterogeneity, possibly consistent with Biomphalaria habitat suitability. Water catchment area may represent a valuable and underutilised unit for targeting schistosomiasis surveillance and control in Madagascar.

Invasive mosquito species pose substantial risks to human and animal health. Since 2004, Culex coronator, a mosquito vector species of public health concern, has shown rapid range expansion within the United States, spreading from a historically limited distribution in southern Texas to across the Gulf Coast region and into eastern and mid-Atlantic states. However, changes in environmental suitability associated with this expansion across historical, contemporary, and future climate conditions have not been evaluated. Here, we used species distribution models (SDMs) to compare predictions of abiotic suitability for Cx. coronator under historic (1960-1989) and recent (2000-2024) climate conditions calibrated on the historical range in the United States. We also created a contemporary SDM based on occurrence records prior to and following species range expansion (1960-2024), and further, to predict potential distributions under current and future climate conditions. Models calibrated on the historical range predicted only modest changes in suitability along the Gulf Coast region and failed to identify large areas of the humid subtropical eastern United States that are now occupied. In contrast, the contemporary model predicted widespread suitability across much of the southern and eastern United States. Future projections under the mid-range SSP3 scenario predicted increasing suitability at higher latitudes and elevations. Across all models, suitability was consistently low in arid and semi-arid regions, including along the historical western range limit, suggesting that moisture availability may constrain Cx. coronator distributions. Together, these results highlight the need to incorporate updated occurrence records when modeling invasive mosquito species to strengthen surveillance and control strategies.

Background: The biological mechanism linking rainfall with leptospirosis transmission is well established, but rigorous quantitative evidence for the insular Caribbean remains scarce, limited mostly to descriptive reports of post-hurricane outbreaks. We aimed to quantify the association between rainfall and leptospirosis incidence in the Dominican Republic, where leptospirosis is endemic, between 2012 and 2026 using a distributed-lag approach. Methods: We conducted an ecological time-series study complemented by a province panel with fixed effects. Case data (5,412 valid cases) were obtained from the national surveillance system (SIP-0276FA51); rainfall data were obtained from 15 INDOMET rain gauge stations across 13 provinces (2000 to 2026). We calculated the cross-correlation function between lagged monthly rainfall (0 to 6 months) and case counts, fitted a negative binomial distributed-lag regression model (lags 0 to 3 months) adjusted for seasonality and trend, triangulated findings with a 13-province fixed-effects panel, compared four rainfall exposure metrics, assessed extreme-rainfall threshold sensitivity, and estimated the population attributable fraction (PAF) with a parametric bootstrap. Results: The rainfall-case association peaked at a 1-month lag (r = 0.551; 95 % CI 0.437-0.647; p < 0.001) and remained significant through 3 months. In the distributed-lag model, all four lags were independently significant, with the 1-month lag showing the strongest effect (incidence rate ratio [IRR] = 1.156 per additional 50mm; 95 % CI 1.090-1.226; p < 0.001). The province panel yielded an almost identical 1-month lag effect (IRR = 1.147; 95 % CI 1.127-1.167). Rainfall above the historical 90th percentile increased case risk the following month (rate ratio = 1.95), with effect magnitude increasing monotonically with threshold stringency. An estimated 28.2 % (95 % CI 19.0-36.6 %) of cases were attributable to rainfall above the recorded historical minimum. Conclusions: Rainfall is a robust, consistent predictor of leptospirosis incidence in the Dominican Republic, with the strongest association observed at a 1-month lag and a lag pattern broadly consistent with findings from distributed-lag studies in Thailand and the Philippines. These findings, which to our knowledge constitute the first formal quantification of this association for the insular Caribbean, provide an evidence base for rainfall-linked early-warning systems, with the strongest signal at approximately one month and elevated risk extending through three months after rainfall.

Background: Cutaneous leishmaniasis (CL) remains a major neglected tropical disease in Afghanistan; however, recent nationwide evidence on its geographical and temporal distribution is limited. This study assessed the reported burden, spatial distribution and seasonal variation of cutaneous leishmaniasis across Afghanistan during 2024. Methods: A nationwide retrospective ecological study was conducted using aggregated routine surveillance data obtained from the National Malaria and Other Vector-Borne Diseases Program. All cases reported from government health facilities across Afghanistans 34 provinces between 1 January and 31 December 2024 were included. Reported incidence rates were calculated per 10,000 population using national and subnational population estimates. Cases were analyzed by surveillance classification, province, city, rural district, month, and season. Results: A total of 87,245 cases were reported during 2024, corresponding to an overall incidence of 25.1/10,000 population. Anthroponotic and zoonotic CL accounted for 80,202 (91.9%) and 7,043 (8.1%) cases, respectively. Jowzjan recorded the highest provincial incidence (105.0/10,000), while Kabul and Herat contributed the largest absolute numbers of cases. Shiberghan had the highest urban incidence, whereas Panjwai, Ghoryan and Hazrat-e-Sultan recorded exceptionally high rural rates. May had the highest monthly burden, while August had the lowest. Autumn accounted for the largest seasonal proportion (27.92%), whereas summer had the lowest burden (16.98%). Considerable incompleteness in district-level reporting was observed. Conclusion: CL constituted a substantial but highly concentrated public health burden in Afghanistan during 2024. Strengthened surveillance, improved diagnostic confirmation and geographically targeted case-management and vector-control interventions are particularly needed in identified high-burden provinces, cities and rural districts.

AimThe present study investigated the significance of iron in regulating megakaryopoiesis, by a diet-based intervention in an in-vivo model. MethodsMale C57BL/6 mice, aged 4-5 weeks were fed on varying iron diets. Following sacrifice, blood samples collected in EDTA tubes were used to analyse haematological parameters, and iron content of liver and spleen was assessed by biochemical analyses. Megakaryocyte-erythroid progenitors (MEPs) were isolated from bone marrow by magnetic bead-based selection. RNA isolated from bone marrow cells and MEPs were used for gene expression analyses, and RNA Sequencing to identify differentially expressed genes (DEGs) and associated pathways. ResultsMice fed on an iron-deficient diet had reduced hepatic iron content after 5 weeks (p < 0.01), while both the hepatic and spleen iron content increased after 3 weeks in mice on an iron-rich diet (p < 0.05) and developed iron overloading. Hb and RBC counts increased (p < 0.05) in iron-rich mice and decreased in iron-deficient mice (p < 0.05), which also showed elevated platelet counts (p < 0.01). This may be explained by increased expression of Gata1, Tal1 (p < 0.01) Mds1 and Pdpk1 (p < 0.05) in bone marrow cells from iron-deficient mice. MEPs isolated from these mice showed elevated expression of genes associated with megakaryocytic differentiation, platelet functions, and genes encoding TGF-{beta}R1 and Smad 2,3 and 4. ConclusionsIron deficiency may activate TGF-{beta} signalling and downstream Smad-mediated transcriptional programs within MEPs. This may promote a shift in lineage commitment towards megakaryopoiesis through elevated expression of megakaryopoiesis related genes.

Background Floods are among the most devastating natural disasters worldwide and are increasingly associated with adverse mental health outcomes, particularly Post-Traumatic Stress Disorder (PTSD). In December 2023, Hanang District in northern Tanzania experienced catastrophic mud floods that resulted in extensive loss of life, destruction of property, displacement of households, and disruption of livelihoods. While emergency humanitarian responses focused primarily on physical needs, limited evidence exists regarding the long-term psychological consequences among survivors. Therefore, this study aimed to determine the patterns of PTSD manifestations and assess cognitive factors associated with PTSD symptoms among flood victims in Hanang District, Tanzania. Methods A community-based cross-sectional study was conducted among 360 flood victims one year after the disaster. PTSD symptoms were assessed using the PTSD Checklist for DSM-5 (PCL-5). Descriptive statistics summarized PTSD severity, while chi-square tests and regression analyses examined associations between socio-demographic characteristics and PTSD manifestations. Cognitive factors were assessed based on participants' exposure to traumatic experiences and perceptions of traumatic events. Results The mean PCL-5 score was 39.2 (SD = 20.6), indicating a high burden of psychological distress. Approximately 45% of respondents had severe PTSD symptoms (PCL-5 [&ge;]45), while another substantial proportion demonstrated moderate symptom severity. PTSD manifestations varied significantly by geographical location (p < 0.001), household income (p = 0.011), and marital status (p = 0.002). Age positively predicted PTSD severity ({beta} = 0.019, p = 0.001), whereas household income negatively predicted symptom severity ({beta} = -0.297, p = 0.001). Exposure to natural disasters constituted the predominant cognitive factor, with 45% directly experiencing the flood and 38.3% witnessing the event. Exposure to secondary traumatic experiences through witnessing or learning about violent events was also common. Cognitive trauma exposure demonstrated a significant association with PTSD symptoms ({chi}2, p < 0.001). Conclusion PTSD remains highly prevalent among flood survivors in Hanang district. Both direct and indirect trauma exposure significantly contributed to PTSD manifestations. Comprehensive disaster recovery programmes should integrate trauma-focused psychological services, cognitive behavioural interventions, routine PTSD screening, and community-based psychosocial support alongside socioeconomic recovery initiatives.

Background: Natural compounds from avocado fruit (avocadene, avocadyne, and acetate derivatives) exhibit notable biological activity, although their molecular mechanisms remain unclear. The avocado-derived lipids exert potent nematocidal activity against several parasitic nematodes. In Caenorhabditis elegans (C. elegans), those compounds caused concentration-dependent toxicity, impairing first stage larval growth, egg hatching, and adult survival. Treated worms exhibited impaired mitochondrial respiration, reduced oxygen consumption, and elevated reactive oxygen species. These effects suggest that avocado lipids disrupt mitochondrial function and lipid metabolism, in part by inhibiting acetyl-CoA carboxylase, the rate-limiting enzyme of fatty acid biosynthesis. Methods: We investigated the effects of these compounds on the lipid profile of C. elegans and their association with endogenous lipid pools using NMR spectroscopy, click-chemistry-based fluorescence labeling, thin-layer chromatography (TLC), and microscopy. Results: Lipidomic analysis of stage 4 larvae (L4) and embryos treated with avocadene acetate revealed increased lipid NMR signals. Fluorescence-assisted TLC and NMR further suggested that avocadyne preferentially associates with triglyceride-linked fatty acids, particularly monounsaturated and flexible polyunsaturated chains, without detectable interactions with conformationally-constrained polyunsaturated species. Fluorescent avocadyne derivatives were efficiently internalized with distinct localization patterns in L4 larvae and embryonic cells. Conclusions: Overall, the lipid homeostasis remodeling of L4 larvae in response to lipotoxic shock was associated with phospholipid increase and remarkable lipid droplets onset, whereas embryos showed accumulation of lipids in enlarged droplets and developmental arrest.

Monogenean capsalids of the genus Neobenedenia are widespread parasites of wild and farmed marine fish, and represent a great threat to the mariculture of grouper in China. Fishery drug development to screen and find effective compounds to control and prevent the disease is urgent needed, considering the vast production of grouper in China (294 ktons in 2025). Annexins have been discovered in Neobenedenia and other parasites, and marked differences between the parasite annexins and those of the hosts make them potentially attractive drug targets for anti-parasite therapeutics. Herein, we utilized computer-based drug discovery screens using unique Neobenedenia melleni annexin B1 and a database of 1,456,161 small molecules. The 3D structure of annexin B1 was firstly modeled by three different protein prediction tools, namely AlphaFold 3, SWISS-MODEL, and I-TASSER, of which the most accurate protein structure was used as the drug target for the following structure-based virtual screening. In vivo experimental validation of 11 compounds after molecular docking shows that abamectin (Aba) has the most effective anti-Neobenedenia bioactivity at the concentration of 0.16 mg/L as the initial screening concentration. Given its low toxicity to host grouper (24 LC50=0.254 mg/L), abamectin was chose for further investigation. A 24 h bath exposure successfully lowered the parasitic load in infected grouper, yielding an 24 h EC50 of 0.033 mg. To elucidate the anti-parasite mechanism, long-timescale molecular dynamics simulations (1000 ns) of annexin B1 and Aba was conducted, which allowed for atomic and molecular-level analysis of the essential protein motions involved in the interaction of annexin B1 and its substrate. The interaction profile between annexin B1 and abamectin was dominated by hydrophobic contacts and water bridges, involving residues TYR-210, GLU-214, GLU-244, and SER-247, which path a way for further drug optimization.

Background On the Zanzibar islands, Tanzania, mass drug administration (MDA) with praziquantel against Schistosoma haematobium infections has been implemented regularly since the early 2000s. Elimination of schistosomiasis as a public health problem has been achieved in most areas, with the goal of interruption of transmission. The RESIST project investigates the extent to which MDA-driven selection for praziquantel resistance is occurring and contributing to persistent transmission hotspots. Methodology As part of RESIST, the efficacy of praziquantel treatment was assessed in two schools on Pemba between October 2024 and March 2025. Longitudinal parasitological surveys were conducted before and two weeks after school-based MDA with praziquantel (40 mg/kg). Up to six urine samples per study participant were collected on different days pre- and post-MDA and examined for S. haematobium eggs by urine filtration microscopy. In a per-protocol analysis, drug efficacy was categorised as adequate, inconclusive, or reduced, based on hypothesis testing. A generalized linear mixed model was used to assess the association between pre-MDA infection intensity and drug efficacy at the individual level. Principal findings Pre-MDA, S. haematobium prevalence was 14.3% (62/434) in School 1 and 37.8% (233/617) in School 2. Post-MDA prevalence was 0.5% (2/434) and 9.6% (59/617), respectively. Egg reduction rates were 99.8% (90% confidence interval (CI): 99.2-100%) in School 1 and 94.8% (90% CI: 88.6-98.6%) in School 2, which were classified as adequate and inconclusive, respectively. In School 2, drug efficacy at the individual level was negatively associated with pre-MDA infection intensity. Conclusion/significance The efficacy of praziquantel on Pemba remains higher than the 90% threshold for optimal drug efficacy set by the World Health Organization. While the inconclusive efficacy results for School 2 can at least partially be explained by the variation in the participants pre-MDA infection intensities, further investigations are warranted to account for the disparity in praziquantel efficacy on Pemba. Trial registration: ISRCTN, ISRCTN59331501. Registered 24 October 2024, https://www.isrctn.com/ISRCTN59331501.

BackgroundVietnams reported dengue burden has risen roughly five-fold since 1990. Multi-decadal studies linking climate indices to dengue rarely separate genuine year-to-year coupling from a long-term trend the two share. MethodsWe assembled a provenance-preserving national annual dengue series (1990-2025; OpenDengue plus Ministry of Health figures) and correlated it with annual and March-May means of eight tropical sea surface temperature (SST) indices at lags of zero and one year under five trend-correction lenses: raw, linear detrending, first-differencing, socio-demographic-index residualisation and AR(1) prewhitening. FindingsCases rose 3{middle dot}5 percent annually. Seven predictors were significant at zero lag, led by the annual Indian Ocean Basin-Wide index (IOBW; Spearman +0{middle dot}534), but linear detrending removed all. First-differencing preserved six, led by spring IOBW (+0{middle dot}468), the annual Atlantic Multidecadal Oscillation (AMO; +0{middle dot}462) and annual IOBW (+0{middle dot}423); three survived AR(1) prewhitening - annual AMO and annual and spring IOBW. Spring AMO and a lag-1 Tropical North Atlantic signal (-0{middle dot}452) did not, and are hypothesis-generating. El Nino-Southern Oscillation indices failed throughout. InterpretationMost of the apparent association reflects a trend shared by warming oceans and expanding surveillance; we could not demonstrate that climate is the primary driver at this scale. Trend is not the whole story: IOBW and annual AMO persist under trend- and persistence-removing transformations. Because transmission responds to climate over weeks to months, annual averaging smooths the lags through which El Nino acts; these nulls reflect temporal scale, not climate insensitivity; usable predictors will require monthly, province-level models. FundingCenter for Environmental Intelligence, VinUniversity (project VUNI.CEI.FS_0001). Research in contextO_ST_ABSEvidence before this studyC_ST_ABSWe searched PubMed, Web of Science and Google Scholar for studies published up to May 2026 linking large-scale climate indices or sea surface temperature to dengue incidence, combining dengue, climate, sea surface temperature, ENSO, teleconnection and time-series terms with Vietnam, without language restriction. Many studies covering two or more decades reported strong correlations between basin-scale indices and national dengue counts. Most, however, relied on raw correlations or a single detrending choice, and rarely tested whether an apparent association reflected genuine year-to-year coupling or merely a shared long-term trend. Added value of this studyMost long-term studies remove the shared upward trend in only one way, or not at all. To our knowledge this is the first study to compare five trend-correction methods on a multi-decadal national dengue record and to read their agreement or disagreement as a diagnostic of which climate signals are real. A signal that appears only before the trend is removed is probably following it; one that persists is more likely real. Applied to a record spanning more than three decades, this comparison separates the two: several widely reported raw correlations weakened once the shared trend was accounted for. Implications of all the available evidenceClimate-informed analyses of multi-decadal data should report at least two trend-correction approaches alongside the raw correlation and treat their disagreement as evidence about where a signal sits, rather than operationalising raw long-span correlations. For Vietnam, the apparent national-scale association is dominated by a shared long-term trend but retains a smaller, robust inter-annual component led by the Indian Ocean and AMO signals; genuine coupling is more likely detectable at monthly resolution and provincial scale, where statistical power and physical mechanism are jointly available. Surveillance systems should retain explicit source provenance, so trend-corrected re-analysis remains possible as records grow.