Pub Date : 2025-12-05DOI: 10.1016/j.actatropica.2025.107937
Attila J Trájer
The invasive bridge vector mosquito Aedes albopictus has been increasingly detected across Europe, posing potential risks for arboviral disease transmission. Urban-scale assessments of its expansion remain scarce in Central Europe. The establishment and spread of Ae. albopictus in Budapest were analysed between 2018 and 2025 using spatio-temporal mapping, seasonal observations, and indicator-based ecological modelling, complemented by ensemble machine learning approaches. Occurrence patterns followed a logistic growth trajectory (R² = 0.995), with colonization rising from sparse foci in 2020 to over 85% of districts by 2025. Seasonal activity extended from late April to mid-October, peaking in early September. Ensemble machine learning models consistently achieved high predictive performance, with key predictors included urban fabric, temperature, topography, and precipitation-related indices (bio18; Köppen Aridity Index) while other factors contributed variably. Ecological associations were strongest with urbanized land cover (discontinuous and continuous urban fabric, industrial areas), specific soil types such as fluvent entisols, and humid temperate climates (Köppen Cfa). K-means clustering and decision tree analyses distinguished seven ecological clusters across Budapest, ranging from warm, densely built urban cores to cooler, shaded peri‑urban and forested zones. Conceptually linking ecological clusters to the Sustainable Development Goals highlighted spatially heterogeneous intersections with health (SDG 3), urban sustainability (SDG 11), water management (SDG 6), climate action (SDG 13), and biodiversity conservation (SDG 15). These findings provide a baseline for predicting urban vector expansion, informing early warning systems, and guiding public health interventions and vector control strategies in European metropolitan regions.
{"title":"Ecological determinants and indicator-based analysis of Aedes albopictus expansion in a Central European metropolis: implications for urban sustainability","authors":"Attila J Trájer","doi":"10.1016/j.actatropica.2025.107937","DOIUrl":"10.1016/j.actatropica.2025.107937","url":null,"abstract":"<div><div>The invasive bridge vector mosquito <em>Aedes albopictus</em> has been increasingly detected across Europe, posing potential risks for arboviral disease transmission. Urban-scale assessments of its expansion remain scarce in Central Europe. The establishment and spread of <em>Ae. albopictus</em> in Budapest were analysed between 2018 and 2025 using spatio-temporal mapping, seasonal observations, and indicator-based ecological modelling, complemented by ensemble machine learning approaches. Occurrence patterns followed a logistic growth trajectory (R² = 0.995), with colonization rising from sparse foci in 2020 to over 85% of districts by 2025. Seasonal activity extended from late April to mid-October, peaking in early September. Ensemble machine learning models consistently achieved high predictive performance, with key predictors included urban fabric, temperature, topography, and precipitation-related indices (bio18; Köppen Aridity Index) while other factors contributed variably. Ecological associations were strongest with urbanized land cover (discontinuous and continuous urban fabric, industrial areas), specific soil types such as fluvent entisols, and humid temperate climates (Köppen Cfa). K-means clustering and decision tree analyses distinguished seven ecological clusters across Budapest, ranging from warm, densely built urban cores to cooler, shaded peri‑urban and forested zones. Conceptually linking ecological clusters to the Sustainable Development Goals highlighted spatially heterogeneous intersections with health (SDG 3), urban sustainability (SDG 11), water management (SDG 6), climate action (SDG 13), and biodiversity conservation (SDG 15). These findings provide a baseline for predicting urban vector expansion, informing early warning systems, and guiding public health interventions and vector control strategies in European metropolitan regions.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107937"},"PeriodicalIF":2.5,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145699349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-04DOI: 10.1016/j.actatropica.2025.107934
Sudarson Sundarrajan , Santharam S Katta , Sridhar KN , Suraj Jagtap , Nagaraj C
Dengue is an endemic disease in over 100 countries, causing an estimated 500,000 hospitalizations each year. The global mortality rate for severe dengue infections is around 2.5 %. India is a major dengue hotspot, accounting for almost a third of all global cases. Despite this significant burden, there are limited studies on the circulating serotypes and genetic lineages of the dengue virus (DENV) within the country. This retrospective study investigates the distribution and genetic diversity of circulating dengue virus (DENV) variants based on clinical samples collected from healthcare centres between 2019 and 2024 in South India. A total of 1015 samples from dengue patients tested positive for at least one of the dengue NS1, IgM, or IgG markers. Among these, 210 NS1-positive samples underwent DENV serotyping via RT-PCR, and 84 of those were further characterized through Sanger sequencing of the C-prM gene to determine genotype and lineage associations. The analysis revealed a decline in dengue infection rates with increasing age, supported by a corresponding rise in IgG seropositivity. Notably, individuals under 20 years of age exhibited a significantly higher frequency of severe disease compared to older age groups. All four DENV serotypes, DENV-1 through DENV-4, were detected across the study period, with a shift in dominant serotype approximately every 2–3 years. DENV-2 and DENV-3 emerged as the most prevalent serotypes. Phylogenetic analysis identified the following genotype-lineage associations: DENV-1 as Genotype III (Lineage: 1III_A), DENV-2 as Genotype II (Cosmopolitan) (Lineages: 2II_A and 2II_F), DENV-3 as Genotype III (Lineage: 3III_B), and DENV-4 as Genotype I (Lineage: 4I_B). These findings underscore the dynamic nature of dengue virus transmission and genetic evolution in the region, emphasizing the importance of age-specific surveillance and targeted prevention strategies. This study contributes valuable insights into local DENV circulation patterns, which are critical for informing diagnostic, therapeutic, and vaccine development efforts.
{"title":"Temporal genomic diversity of Dengue virus in South India from 2019 to 2024","authors":"Sudarson Sundarrajan , Santharam S Katta , Sridhar KN , Suraj Jagtap , Nagaraj C","doi":"10.1016/j.actatropica.2025.107934","DOIUrl":"10.1016/j.actatropica.2025.107934","url":null,"abstract":"<div><div>Dengue is an endemic disease in over 100 countries, causing an estimated 500,000 hospitalizations each year. The global mortality rate for severe dengue infections is around 2.5 %. India is a major dengue hotspot, accounting for almost a third of all global cases. Despite this significant burden, there are limited studies on the circulating serotypes and genetic lineages of the dengue virus (DENV) within the country. This retrospective study investigates the distribution and genetic diversity of circulating dengue virus (DENV) variants based on clinical samples collected from healthcare centres between 2019 and 2024 in South India. A total of 1015 samples from dengue patients tested positive for at least one of the dengue NS1, IgM, or IgG markers. Among these, 210 NS1-positive samples underwent DENV serotyping via RT-PCR, and 84 of those were further characterized through Sanger sequencing of the C-prM gene to determine genotype and lineage associations. The analysis revealed a decline in dengue infection rates with increasing age, supported by a corresponding rise in IgG seropositivity. Notably, individuals under 20 years of age exhibited a significantly higher frequency of severe disease compared to older age groups. All four DENV serotypes, DENV-1 through DENV-4, were detected across the study period, with a shift in dominant serotype approximately every 2–3 years. DENV-2 and DENV-3 emerged as the most prevalent serotypes. Phylogenetic analysis identified the following genotype-lineage associations: DENV-1 as Genotype III (Lineage: 1III_A), DENV-2 as Genotype II (Cosmopolitan) (Lineages: 2II_A and 2II_F), DENV-3 as Genotype III (Lineage: 3III_B), and DENV-4 as Genotype I (Lineage: 4I_B). These findings underscore the dynamic nature of dengue virus transmission and genetic evolution in the region, emphasizing the importance of age-specific surveillance and targeted prevention strategies. This study contributes valuable insights into local DENV circulation patterns, which are critical for informing diagnostic, therapeutic, and vaccine development efforts.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107934"},"PeriodicalIF":2.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145695902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-04DOI: 10.1016/j.actatropica.2025.107933
Amirreza Meydani , Shuai Wang , Robert Bergquist , Flavio Lopes Ribeiro , Delphis F. Levia
Extreme climate variables are increasingly important for understanding the distribution of Biomphalaria snails, the intermediate hosts of Schistosoma mansoni. While many studies focus on long-term averages, our approach emphasizes the role of climatic extreme events and their seasonal timing in shaping habitat persistence. We applied spatially explicit Random Forest (RF) species distribution models with spatial cross-validation and bootstrap aggregation to produce robust and transferable predictions of snail habitat suitability, and then ranked the influence of extreme climate variables using SHapley Additive exPlanations (SHAP) values and partial dependence plots. The models performed well, with average area under curve (AUC) values of 0.75 across species and partial AUC ratios greater than one, confirming the robustness of the predictions. Precipitation seasonality, multi-month drought indices, surface absorbed solar radiation extremes, and diurnal air temperature range were the highest-ranked drivers, though their influence was not uniform across snail species. Biomphalaria glabrata was most responsive to seasonal recharge, while B. straminea showed resilience to variability and often persisted in man-made habitats. Biomphalaria tenagophila was more constrained by drought and radiation stress. Spatial comparisons between 1995 and 2020 indicated expansions and contractions in various states, with new hotspots emerging in southeastern and central Brazil, while habitat suitability declined in drought-prone regions, such as in the State of Pernambuco. These results demonstrate that climate extreme events, in addition to long-term baseline changes, drive the spatially heterogeneous redistribution of Biomphalaria habitats. Also, our findings highlight the need for species-specific monitoring, integration of water infrastructure management, and forward-looking surveillance strategies that address both climate variability and landscapes modified by humans.
{"title":"Climate extremes and the dynamic reshaping of snail habitat: implications for the spatiotemporal heterogeneity of schistosomal vulnerability in Brazil","authors":"Amirreza Meydani , Shuai Wang , Robert Bergquist , Flavio Lopes Ribeiro , Delphis F. Levia","doi":"10.1016/j.actatropica.2025.107933","DOIUrl":"10.1016/j.actatropica.2025.107933","url":null,"abstract":"<div><div>Extreme climate variables are increasingly important for understanding the distribution of <em>Biomphalaria</em> snails, the intermediate hosts of <em>Schistosoma mansoni</em>. While many studies focus on long-term averages, our approach emphasizes the role of climatic extreme events and their seasonal timing in shaping habitat persistence. We applied spatially explicit Random Forest (RF) species distribution models with spatial cross-validation and bootstrap aggregation to produce robust and transferable predictions of snail habitat suitability, and then ranked the influence of extreme climate variables using SHapley Additive exPlanations (SHAP) values and partial dependence plots. The models performed well, with average area under curve (AUC) values of 0.75 across species and partial AUC ratios greater than one, confirming the robustness of the predictions. Precipitation seasonality, multi-month drought indices, surface absorbed solar radiation extremes, and diurnal air temperature range were the highest-ranked drivers, though their influence was not uniform across snail species. <em>Biomphalaria glabrata</em> was most responsive to seasonal recharge, while <em>B. straminea</em> showed resilience to variability and often persisted in man-made habitats. <em>Biomphalaria tenagophila</em> was more constrained by drought and radiation stress. Spatial comparisons between 1995 and 2020 indicated expansions and contractions in various states, with new hotspots emerging in southeastern and central Brazil, while habitat suitability declined in drought-prone regions, such as in the State of Pernambuco. These results demonstrate that climate extreme events, in addition to long-term baseline changes, drive the spatially heterogeneous redistribution of <em>Biomphalaria</em> habitats. Also, our findings highlight the need for species-specific monitoring, integration of water infrastructure management, and forward-looking surveillance strategies that address both climate variability and landscapes modified by humans.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107933"},"PeriodicalIF":2.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145686802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.actatropica.2025.107931
Caroline M. Meira , Anna V. Serafim , Edson A. Adriano , Antonio A.M. Maia
Myxozoa are a highly diverse group of cnidarian parasites, with approximately 3070 described species. This study describes a new species, Myxobolus mirandensis n. sp., based on morphological, molecular, and histopathological analyses. The parasite was found in Salminus brasiliensis (dourado), one of the largest and most economically and recreationally important freshwater fish species in South America. Specimens of S. brasiliensis were collected from the Miranda River in the Brazilian Pantanal, with a prevalence of the infection of 63.6 % (7/11). White and elongated plasmodia were observed in the gill filaments. Pear-shaped myxospores measured 10.1 ± 0.3 µm in length, 6.6 ± 0.3 µm in width, and 5.1 ± 0.1 µm in thickness. Nematocysts were elongated and occupied more than half of the spore body, measuring 4.9 ± 0.3 µm in length and 1.9 ± 0.2 µm in width. Histopathological analysis revealed plasmodia developing in the epithelial tissue at the distal ends of the gill filaments, resulting in compression of adjacent tissues and structures. A thin connective tissue capsule surrounded the plasmodia, and numerous granulocytic cells were observed in the tissue adjacent to the plasmodia. Sequencing of the small subunit ribosomal DNA (SSU rDNA) yielded a 1954 bp fragment. Phylogenetic analysis showed M. mirandensis grouping with Myxobolus oliveirai and Myxobolus filamentum, both reported in Bryconidae hosts. This represents the seventh record of a myxozoan infecting S. brasiliensis.
{"title":"Taxonomy and histopathology of Myxobolus mirandensis n. sp. parasite of the gills of Salminus brasiliensis from the Brazilian Pantanal wetland","authors":"Caroline M. Meira , Anna V. Serafim , Edson A. Adriano , Antonio A.M. Maia","doi":"10.1016/j.actatropica.2025.107931","DOIUrl":"10.1016/j.actatropica.2025.107931","url":null,"abstract":"<div><div>Myxozoa are a highly diverse group of cnidarian parasites, with approximately 3070 described species. This study describes a new species, <em>Myxobolus mirandensis</em> n. sp., based on morphological, molecular, and histopathological analyses. The parasite was found in <em>Salminus brasiliensis</em> (dourado), one of the largest and most economically and recreationally important freshwater fish species in South America. Specimens of <em>S. brasiliensis</em> were collected from the Miranda River in the Brazilian Pantanal, with a prevalence of the infection of 63.6 % (7/11). White and elongated plasmodia were observed in the gill filaments. Pear-shaped myxospores measured 10.1 ± 0.3 µm in length, 6.6 ± 0.3 µm in width, and 5.1 ± 0.1 µm in thickness. Nematocysts were elongated and occupied more than half of the spore body, measuring 4.9 ± 0.3 µm in length and 1.9 ± 0.2 µm in width. Histopathological analysis revealed plasmodia developing in the epithelial tissue at the distal ends of the gill filaments, resulting in compression of adjacent tissues and structures. A thin connective tissue capsule surrounded the plasmodia, and numerous granulocytic cells were observed in the tissue adjacent to the plasmodia. Sequencing of the small subunit ribosomal DNA (SSU rDNA) yielded a 1954 bp fragment. Phylogenetic analysis showed <em>M. mirandensis</em> grouping with <em>Myxobolus oliveirai</em> and <em>Myxobolus filamentum</em>, both reported in Bryconidae hosts. This represents the seventh record of a myxozoan infecting <em>S. brasiliensis</em>.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"272 ","pages":"Article 107931"},"PeriodicalIF":2.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145676165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Crimean-Congo hemorrhagic fever virus (CCHFV) is endemic in >30 countries across Asia, Europe, the Middle East, and Africa. CCHFV causes Crimean-Congo hemorrhagic fever (CCHF), a disease characterized by bleeding and haemoptysis. Since the first diagnosis in 1944, 10,000–15,000 CCHF cases are reported worldwide annually. Around three billion people are at risk of CCHFV infection. The World Health Organization (WHO) announced CCHFV as a priority pathogen in December 2015 due to its widespread and significant healthcare threat. In this review, we track the outbreaks, discuss their origin, and analyze the geographical spread of the CCHFV. We will also discuss reservoirs, the modes of transmission, and the factors influencing CCHFV infection. Preventive measures will be highlighted with emphasis on the potential of artificial intelligence in outbreak prediction and disease surveillance.
{"title":"Epidemiology of the Crimean-Congo hemorrhagic fever virus","authors":"Neha Kaushal , Sahil Jain , Dimple Davray , Albert Rizvanov , Ming-Hsien Chiang , Olesia Ohlopkova , Svetlana Khaiboullina , Ze Chen , Manoj Baranwal","doi":"10.1016/j.actatropica.2025.107917","DOIUrl":"10.1016/j.actatropica.2025.107917","url":null,"abstract":"<div><div>Crimean-Congo hemorrhagic fever virus (CCHFV) is endemic in >30 countries across Asia, Europe, the Middle East, and Africa. CCHFV causes Crimean-Congo hemorrhagic fever (CCHF), a disease characterized by bleeding and haemoptysis. Since the first diagnosis in 1944, 10,000–15,000 CCHF cases are reported worldwide annually. Around three billion people are at risk of CCHFV infection. The World Health Organization (WHO) announced CCHFV as a priority pathogen in December 2015 due to its widespread and significant healthcare threat. In this review, we track the outbreaks, discuss their origin, and analyze the geographical spread of the CCHFV. We will also discuss reservoirs, the modes of transmission, and the factors influencing CCHFV infection. Preventive measures will be highlighted with emphasis on the potential of artificial intelligence in outbreak prediction and disease surveillance.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"272 ","pages":"Article 107917"},"PeriodicalIF":2.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145538553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.actatropica.2025.107925
Selda Şahan , Seher Topluoğlu , Fehminaz Temel , Yasemin Coşgun , Erdoğan Öz , Muhammed Emin Demirkol , Şuayıp Birinci
Crimean-Congo haemorrhagic fever (CCHF) is a major public health concern in Türkiye, which has the highest global incidence. This study analysed national surveillance data from 2011 to 2024 to describe the epidemiology of CCHF and identify predictors of fatality through a retrospective cohort analysis using the CCHF Information System. All laboratory-confirmed cases reported between 2011 and 2024 were included. Descriptive statistics summarized demographic, clinical, and laboratory variables. Logistic regression was applied to determine fatality predictors, and adjusted odds ratios (ORadj) with 95 % confidence intervals (CI) were calculated. Among 27,269 samples tested, 11,811 cases were laboratory-confirmed, of which 552 died (case fatality rate: 4.7 %). Males comprised 60.5 % of cases, and the mean age was 46.8 ± 18.5 years. Tick-bite or tick contact (62.2 %) and close contact with animal blood or tissues (69.6 %) were common exposure histories. Fatality was independently associated with increasing age (ORadj: 1.034; 95 % CI: 1.029–1.040), male sex (ORadj: 1.3; 95 % CI: 1.1–1.6), splenomegaly (ORadj: 2.0; 95 % CI: 1.5–2.7), haemorrhagic findings (ORadj: 2.4; 95 % CI: 2.0–3.0), platelet count <20,000/mm³ (ORadj: 10.3; 95 % CI: 6.7–15.7), platelet count 20,000–49,000/mm³ (ORadj: 4.6; 95 % CI: 3.0–7.0), and elevated AST or ALT (ORadj: 1.5; 95 % CI: 1.1–2.0). Patients who did not receive ribavirin had higher fatality (ORadj: 1.5; 95 % CI: 1.2–2.0). Although Türkiye reports many cases, fatality remains comparatively low. Identified predictors can support early risk stratification and clinical management. Strengthening surveillance, laboratory capacity, and clinician training may further reduce mortality.
{"title":"Evaluation of epidemiological characteristics of Crimean-Congo haemorrhagic fever patients reported to the National Surveillance System in Türkiye, 2011-2024","authors":"Selda Şahan , Seher Topluoğlu , Fehminaz Temel , Yasemin Coşgun , Erdoğan Öz , Muhammed Emin Demirkol , Şuayıp Birinci","doi":"10.1016/j.actatropica.2025.107925","DOIUrl":"10.1016/j.actatropica.2025.107925","url":null,"abstract":"<div><div>Crimean-Congo haemorrhagic fever (CCHF) is a major public health concern in Türkiye, which has the highest global incidence. This study analysed national surveillance data from 2011 to 2024 to describe the epidemiology of CCHF and identify predictors of fatality through a retrospective cohort analysis using the CCHF Information System. All laboratory-confirmed cases reported between 2011 and 2024 were included. Descriptive statistics summarized demographic, clinical, and laboratory variables. Logistic regression was applied to determine fatality predictors, and adjusted odds ratios (ORadj) with 95 % confidence intervals (CI) were calculated. Among 27,269 samples tested, 11,811 cases were laboratory-confirmed, of which 552 died (case fatality rate: 4.7 %). Males comprised 60.5 % of cases, and the mean age was 46.8 ± 18.5 years. Tick-bite or tick contact (62.2 %) and close contact with animal blood or tissues (69.6 %) were common exposure histories. Fatality was independently associated with increasing age (ORadj: 1.034; 95 % CI: 1.029–1.040), male sex (ORadj: 1.3; 95 % CI: 1.1–1.6), splenomegaly (ORadj: 2.0; 95 % CI: 1.5–2.7), haemorrhagic findings (ORadj: 2.4; 95 % CI: 2.0–3.0), platelet count <20,000/mm³ (OR<sub>adj</sub>: 10.3; 95 % CI: 6.7–15.7), platelet count 20,000–49,000/mm³ (OR<sub>adj</sub>: 4.6; 95 % CI: 3.0–7.0), and elevated AST or ALT (OR<sub>adj</sub>: 1.5; 95 % CI: 1.1–2.0). Patients who did not receive ribavirin had higher fatality (OR<sub>adj</sub>: 1.5; 95 % CI: 1.2–2.0). Although Türkiye reports many cases, fatality remains comparatively low. Identified predictors can support early risk stratification and clinical management. Strengthening surveillance, laboratory capacity, and clinician training may further reduce mortality.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"272 ","pages":"Article 107925"},"PeriodicalIF":2.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145627612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.actatropica.2025.107926
Ju-Feng Wang , Ying-Xin Bi , Jiong Yang , Geoff Hide , De-Hua Lai , Zhao-Rong Lun
Trypanosoma bubalisi is a newly identified mammalian trypanosome isolated from a freshwater leech (Hirudinaria manillensis) and the water buffalo (Bubalus bubalis) is considered its host. Despite the detailed morphological description of in vitro cultivated forms of this trypanosome, little is known about its ultrastructure. In this study, a detailed ultrastructure of T. bubalisi was characterized using scanning electron microscopy, transmission electron microscopy and focused ion beam-scanning electron microscopy. Two membrane-bound organelles were identified, multivesicular body-like vesicles (ve1) and large lipid-rich vesicles resembling reservosomes (ve2), alongside an extracellular ‘beads-on-a-string’ structure. These all appear to be associated with endocytosis or secretion. Three-dimensional reconstructions confirmed the organization and distribution of the two membrane-bound organelles. Functional assays using Tomato lectin and Lyso-Tracker demonstrated that ve2 is involved in endocytic uptake and may act as a terminal storage compartment. Compared to the pathogen causing Nagana, Trypanosoma brucei, T. bubalisi showed higher endocytic activity under both 27 °C and 4 °C conditions. These findings suggest that T. bubalisi possesses an active endocytic system and may share conserved mechanisms of material transport and storage with the pathogen causing Chagas’ disease, Tryponosoma cruzi.
{"title":"Ultrastructural and morphological characterization of Trypanosoma bubalisi reveals an active endocytic system","authors":"Ju-Feng Wang , Ying-Xin Bi , Jiong Yang , Geoff Hide , De-Hua Lai , Zhao-Rong Lun","doi":"10.1016/j.actatropica.2025.107926","DOIUrl":"10.1016/j.actatropica.2025.107926","url":null,"abstract":"<div><div><em>Trypanosoma bubalisi</em> is a newly identified mammalian trypanosome isolated from a freshwater leech (<em>Hirudinaria manillensis</em>) and the water buffalo (<em>Bubalus bubalis</em>) is considered its host. Despite the detailed morphological description of <em>in vitro</em> cultivated forms of this trypanosome, little is known about its ultrastructure. In this study, a detailed ultrastructure of <em>T. bubalisi</em> was characterized using scanning electron microscopy, transmission electron microscopy and focused ion beam-scanning electron microscopy. Two membrane-bound organelles were identified, multivesicular body-like vesicles (ve1) and large lipid-rich vesicles resembling reservosomes (ve2), alongside an extracellular ‘beads-on-a-string’ structure. These all appear to be associated with endocytosis or secretion. Three-dimensional reconstructions confirmed the organization and distribution of the two membrane-bound organelles. Functional assays using Tomato lectin and Lyso-Tracker demonstrated that ve2 is involved in endocytic uptake and may act as a terminal storage compartment. Compared to the pathogen causing Nagana, <em>Trypanosoma brucei, T. bubalisi</em> showed higher endocytic activity under both 27 °C and 4 °C conditions. These findings suggest that <em>T. bubalisi</em> possesses an active endocytic system and may share conserved mechanisms of material transport and storage with the pathogen causing Chagas’ disease, <em>Tryponosoma cruzi</em>.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"272 ","pages":"Article 107926"},"PeriodicalIF":2.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145627685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.actatropica.2025.107929
Amel Youssef Shehab , Engy Mosbah Hassan , Esraa A. Moneer , Heba Essam Sedky , Fatma A. Abdelkader , Mona Mohamed Tolba , Amal Farahat Allam , Heba Elhadad
Cryptosporidiosis remains a major health concern, particularly in immunocompromised individuals, due to limited effective treatment options. Nitazoxanide (NTZ) is currently the only FDA-approved drug for cryptosporidiosis, yet its efficacy is significantly reduced in immunosuppressed hosts. This study evaluated the therapeutic potential of disulfiram, an FDA-approved drug for alcoholism, alone and in combination with NTZ, against Cryptosporidium infection in immunocompromised mice. Forty immunosuppressed Swiss albino mice were divided into five equal groups: uninfected controls, infected untreated, NTZ-treated, disulfiram-treated, and combination-treated (NTZ + disulfiram). All infected mice were orally inoculated with ∼10⁴ Cryptosporidium oocysts and were treated with NTZ (250 mg/kg/day) and/or disulfiram (25 mg/kg/day) for 10 consecutive days. Efficacy was assessed through parasitological, histopathological, and ultrastructural analyses. The combination therapy achieved the highest fecal oocyst reduction: 34.3 % after one week and 88.3 % after two weeks. In comparison, NTZ and disulfiram monotherapies achieved 24 % and 76 % reductions, respectively, at two-weeks mark. In intestinal contents, the combination therapy resulted in 62.6 % oocyst reduction versus 11.4 % for NTZ and 36.2 % for disulfiram at week two post treatment. Histopathological analysis revealed near-complete mucosal restoration in the combination group, whereas monotherapies showed limited or moderate recovery. Transmission electron microscopy confirmed full epithelial regeneration only in the dual therapy group, with intact microvilli, normal mitochondria, and restored cellular junctions. In conclusion, disulfiram, particularly when combined with NTZ, demonstrated enhanced anti-cryptosporidial efficacy and may serve as a promising adjunct therapy, mostly for immunocompromised patients.
{"title":"Repurposing disulfiram in a promising combination therapy for cryptosporidiosis in immunocompromised mice","authors":"Amel Youssef Shehab , Engy Mosbah Hassan , Esraa A. Moneer , Heba Essam Sedky , Fatma A. Abdelkader , Mona Mohamed Tolba , Amal Farahat Allam , Heba Elhadad","doi":"10.1016/j.actatropica.2025.107929","DOIUrl":"10.1016/j.actatropica.2025.107929","url":null,"abstract":"<div><div>Cryptosporidiosis remains a major health concern, particularly in immunocompromised individuals, due to limited effective treatment options. Nitazoxanide (NTZ) is currently the only FDA-approved drug for cryptosporidiosis, yet its efficacy is significantly reduced in immunosuppressed hosts. This study evaluated the therapeutic potential of disulfiram, an FDA-approved drug for alcoholism, alone and in combination with NTZ, against <em>Cryptosporidium</em> infection in immunocompromised mice. Forty immunosuppressed Swiss albino mice were divided into five equal groups: uninfected controls, infected untreated, NTZ-treated, disulfiram-treated, and combination-treated (NTZ + disulfiram). All infected mice were orally inoculated with ∼10⁴ <em>Cryptosporidium</em> oocysts and were treated with NTZ (250 mg/kg/day) and/or disulfiram (25 mg/kg/day) for 10 consecutive days. Efficacy was assessed through parasitological, histopathological, and ultrastructural analyses. The combination therapy achieved the highest fecal oocyst reduction: 34.3 % after one week and 88.3 % after two weeks. In comparison, NTZ and disulfiram monotherapies achieved 24 % and 76 % reductions, respectively, at two-weeks mark. In intestinal contents, the combination therapy resulted in 62.6 % oocyst reduction versus 11.4 % for NTZ and 36.2 % for disulfiram at week two post treatment. Histopathological analysis revealed near-complete mucosal restoration in the combination group, whereas monotherapies showed limited or moderate recovery. Transmission electron microscopy confirmed full epithelial regeneration only in the dual therapy group, with intact microvilli, normal mitochondria, and restored cellular junctions. In conclusion, disulfiram, particularly when combined with NTZ, demonstrated enhanced anti-cryptosporidial efficacy and may serve as a promising adjunct therapy, mostly for immunocompromised patients.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"272 ","pages":"Article 107929"},"PeriodicalIF":2.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145653134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.actatropica.2025.107927
Nancy E. Rodríguez-Garza , Miguel Marín , Javier Sánchez-Montejo , Ana L. Delgado-Miranda , Aldo F. Bazaldúa-Rodríguez , Ramiro Quintanilla-Licea , Azael Flores-Treviño , César I. Romo-Sáenz , Antonio Muro , Rafael Peláez , Julio López-Abán
Ruta chalepensis L. is a medicinal species widely used in ethnomedicine for gastrointestinal disorders and parasitic diseases. Among its bioactive compounds, the furanocoumarins chalepensin and graveoline have shown antiparasitic activity. This study aimed to evaluate the nematocidal potential of graveoline and chalepensin, isolated from R. chalepensis, against Trichinella spiralis in both in vitro cultures and an experimental in vivo model. The compounds were obtained from leaves and stems and first tested against first-stage larvae (L1) in culture. Selectivity indices (SI) were calculated based on cytotoxicity in Vero cells. Based on in vitro efficacy, chalepensin was selected for evaluation in a murine model of trichinellosis at 50 mg/kg/day administered over three consecutive days against three different infection stages: intestinal (days 0–2), migrating (days 13–15), and encysted (days 34–36). Larvae per gram of muscle were quantified on day 43. Histological sections were analyzed for capsule morphology and inflammation. Additionally, molecular docking was performed to explore potential parasite targets. Both compounds exhibited superior activity compared to the R. chalepensis extract (LC₅₀ = 28.2 µg/mL; SI = 22.4). Chalepensin exhibited strong in vitro activity (LC₅₀ = 0.1 µg/mL; SI = 8561), superior to graveoline (LC₅₀ = 1.1 µg/mL; SI = 162). In vivo, chalepensin reduced larval burden by 90.7% (intestinal), 37.5% (migrating), and 37.0% (encysted). Histology revealed reduced capsule thickness and pericystic inflammation. Docking predicted high affinity for thymidylate synthase (ΔG = –7.175 kcal/mol), suggesting interference with DNA synthesis. Chalepensin demonstrates potent nematocidal activity against T. spiralis, supporting its potential utility as a phytochemical-based therapeutic candidate for the management of trichinellosis.
芦丁是一种广泛应用于胃肠疾病和寄生虫病的民族医学药用植物。其生物活性成分中呋喃香豆素、chalepensin和graveoline具有抗寄生虫活性。本研究旨在评价从chalepensis中分离的graveoline和chalepensin对旋毛虫（Trichinella spiralis）的体外培养和体内实验模型的杀线虫能力。这些化合物从叶片和茎中获得，并在培养中对第一阶段幼虫（L1）进行了初步试验。根据Vero细胞毒性计算选择性指数（SI）。根据体外疗效，选择chalepensin在旋毛虫病小鼠模型中进行评估，剂量为50 mg/kg/天，连续3天给药，针对3个不同的感染阶段：肠道（0-2天）、迁移（13-15天）和成囊（34-36天）。第43天定量测定每克肌肉的幼虫数。组织切片分析胶囊形态及炎症情况。此外，还进行了分子对接，以探索潜在的寄生虫靶点。这两种化合物都比沙勒坡菌提取物具有更强的活性（LC₅₀ = 28.2µg/mL; SI = 22.4）。Chalepensin具有很强的体外活性（LC₅₀ = 0.1µg/mL; SI = 8561），优于砾石碱（LC₅₀ = 1.1µg/mL; SI = 162）。在体内，chalepensin减少了90.7%（肠道）、37.5%（迁移）和37.0%（成囊）的幼虫负担。组织学显示囊膜厚度减小，囊周炎症。对接预测胸苷酸合成酶具有高亲和力（ΔG = -7.175 kcal/mol），提示干扰DNA合成。Chalepensin显示出对螺旋体的有效杀线虫活性，支持其作为一种基于植物化学的治疗旋毛虫病的候选药物的潜在效用。
{"title":"Antiparasitic Efficacy of Chalepensin from Ruta chalepensis L. Against Trichinella spiralis: In Vitro, In Vivo, and Molecular Docking Study","authors":"Nancy E. Rodríguez-Garza , Miguel Marín , Javier Sánchez-Montejo , Ana L. Delgado-Miranda , Aldo F. Bazaldúa-Rodríguez , Ramiro Quintanilla-Licea , Azael Flores-Treviño , César I. Romo-Sáenz , Antonio Muro , Rafael Peláez , Julio López-Abán","doi":"10.1016/j.actatropica.2025.107927","DOIUrl":"10.1016/j.actatropica.2025.107927","url":null,"abstract":"<div><div><em>Ruta chalepensis</em> L. is a medicinal species widely used in ethnomedicine for gastrointestinal disorders and parasitic diseases. Among its bioactive compounds, the furanocoumarins chalepensin and graveoline have shown antiparasitic activity. This study aimed to evaluate the nematocidal potential of graveoline and chalepensin, isolated from <em>R. chalepensis</em>, against <em>Trichinella spiralis</em> in both in vitro cultures and an experimental in vivo model. The compounds were obtained from leaves and stems and first tested against first-stage larvae (L1) in culture. Selectivity indices (SI) were calculated based on cytotoxicity in Vero cells. Based on in vitro efficacy, chalepensin was selected for evaluation in a murine model of trichinellosis at 50 mg/kg/day administered over three consecutive days against three different infection stages: intestinal (days 0–2), migrating (days 13–15), and encysted (days 34–36). Larvae per gram of muscle were quantified on day 43. Histological sections were analyzed for capsule morphology and inflammation. Additionally, molecular docking was performed to explore potential parasite targets. Both compounds exhibited superior activity compared to the <em>R. chalepensis</em> extract (LC₅₀ = 28.2 µg/mL; SI = 22.4). Chalepensin exhibited strong in vitro activity (LC₅₀ = 0.1 µg/mL; SI = 8561), superior to graveoline (LC₅₀ = 1.1 µg/mL; SI = 162). In vivo, chalepensin reduced larval burden by 90.7% (intestinal), 37.5% (migrating), and 37.0% (encysted). Histology revealed reduced capsule thickness and pericystic inflammation. Docking predicted high affinity for thymidylate synthase (ΔG = –7.175 kcal/mol), suggesting interference with DNA synthesis. Chalepensin demonstrates potent nematocidal activity against <em>T. spiralis</em>, supporting its potential utility as a phytochemical-based therapeutic candidate for the management of trichinellosis.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"272 ","pages":"Article 107927"},"PeriodicalIF":2.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145666414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.actatropica.2025.107922
Bárbara da Rocha Fonseca , Guilherme Senna dos Santos , Fernanda Kanaan de Azambuja , Gustavo dos Santos Hartleben , Luiza Domingues Moron , Fernanda Severo Sabedra Souza , Fabiana Kommling Seixas , Tiago Veiras Collares , Edmundo Carlos Grisard , Sibele Borsuk
Chagas disease is a globally widespread parasitic infection caused by the flagellated protozoan Trypanosoma cruzi. It is classified as a neglected tropical disease, primarily affecting impoverished and rural regions where access to diagnosis and treatment is limited. Although treatment for this disease is effective, it is restricted to the acute phase, during which diagnosis is more challenging, reducing cure rates. Consequently, prevention remains the most effective control method, and recombinant proteins offer a promising strategy for vaccine development. Specifically, the proteins ASP-2 and TC24 have demonstrated immunoprotective activity in various experimental models. This study aimed to characterize the immune response elicited by the combined use of recombinant ASP-2 (from the intracellular stage) and TC24 (from the bloodstream stage), seeking to promote a synergistic protective effect compared to the response generated by the proteins used individually. To evaluate this, recombinant proteins rASP-2 and rTC24 were used as vaccine formulations to immunize female BALB/c mice as follows: Group 1: Saline solution; Group 2: 25 µg of rTC24 + aluminum hydroxide; Group 3: 25 µg of rASP-2 + aluminum hydroxide; Group 4: 12.5 µg of rTC24 + 12.5 µg of rASP-2 + aluminum hydroxide. The humoral immune response assessed IgG antibody levels by indirect ELISA of animal sera collected on days 0, 21, and 42 of the experiment, while the cellular response was evaluated by collecting and culturing splenocytes, assessing cytokines IFN-γ, TNF-α, interleukins 1β, 4, 6, 12, 17, and Toll-like receptor 4, quantified by real-time PCR. The results indicated a significant antibody production in the group where the proteins were combined (G4) compared to the control group (G1) on days 21 and 42. A significant increase in antibody production was also observed in group G4 on day 42 when compared to both groups using the isolated proteins (G2 and G3). Conversely, the cellular response showed an increase in IFN-γ and interleukins 1β and 17 in Group D, while the isolated ASP-2 protein induced the expression of TNF-α, interleukins 4 and 12, and Toll-like receptor 4. Western blotting using T. cruzi lysate and pooled serum confirmed the ability of the antibodies to recognize native parasite proteins. In conclusion, the combined use of proteins from different parasite life stages proved advantageous, indicating the induction of a mixed cellular immune response, predominantly of the Th1 and Th17 profiles.
{"title":"Association of recombinant proteins rASP-2 and rTC24 from Trypanosoma cruzi as a vaccine strategy against Chagas disease induces a mixed Th1/ Th17 immune response","authors":"Bárbara da Rocha Fonseca , Guilherme Senna dos Santos , Fernanda Kanaan de Azambuja , Gustavo dos Santos Hartleben , Luiza Domingues Moron , Fernanda Severo Sabedra Souza , Fabiana Kommling Seixas , Tiago Veiras Collares , Edmundo Carlos Grisard , Sibele Borsuk","doi":"10.1016/j.actatropica.2025.107922","DOIUrl":"10.1016/j.actatropica.2025.107922","url":null,"abstract":"<div><div>Chagas disease is a globally widespread parasitic infection caused by the flagellated protozoan <em>Trypanosoma cruzi</em>. It is classified as a neglected tropical disease, primarily affecting impoverished and rural regions where access to diagnosis and treatment is limited. Although treatment for this disease is effective, it is restricted to the acute phase, during which diagnosis is more challenging, reducing cure rates. Consequently, prevention remains the most effective control method, and recombinant proteins offer a promising strategy for vaccine development. Specifically, the proteins ASP-2 and TC24 have demonstrated immunoprotective activity in various experimental models. This study aimed to characterize the immune response elicited by the combined use of recombinant ASP-2 (from the intracellular stage) and TC24 (from the bloodstream stage), seeking to promote a synergistic protective effect compared to the response generated by the proteins used individually. To evaluate this, recombinant proteins rASP-2 and rTC24 were used as vaccine formulations to immunize female BALB/c mice as follows: Group 1: Saline solution; Group 2: 25 µg of rTC24 + aluminum hydroxide; Group 3: 25 µg of rASP-2 + aluminum hydroxide; Group 4: 12.5 µg of rTC24 + 12.5 µg of rASP-2 + aluminum hydroxide. The humoral immune response assessed IgG antibody levels by indirect ELISA of animal sera collected on days 0, 21, and 42 of the experiment, while the cellular response was evaluated by collecting and culturing splenocytes, assessing cytokines IFN-γ, TNF-α, interleukins 1β, 4, 6, 12, 17, and Toll-like receptor 4, quantified by real-time PCR. The results indicated a significant antibody production in the group where the proteins were combined (G4) compared to the control group (G1) on days 21 and 42. A significant increase in antibody production was also observed in group G4 on day 42 when compared to both groups using the isolated proteins (G2 and G3). Conversely, the cellular response showed an increase in IFN-γ and interleukins 1β and 17 in Group D, while the isolated ASP-2 protein induced the expression of TNF-α, interleukins 4 and 12, and Toll-like receptor 4. Western blotting using <em>T. cruzi</em> lysate and pooled serum confirmed the ability of the antibodies to recognize native parasite proteins. In conclusion, the combined use of proteins from different parasite life stages proved advantageous, indicating the induction of a mixed cellular immune response, predominantly of the Th1 and Th17 profiles.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"272 ","pages":"Article 107922"},"PeriodicalIF":2.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145585854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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