Acta tropica最新文献

{"title":"Leptospiral shedding and seropositivity in asymptomatic stray dogs in Bosnia and Herzegovina.","authors":"Jelena Marić, Ivona Subić, Marija Stojiljković, Branislav Stanković, Sonja Obrenović","doi":"10.1016/j.actatropica.2025.107759","DOIUrl":"10.1016/j.actatropica.2025.107759","url":null,"abstract":"<p><p>Leptospirosis is a (re) emerging zoonosis that occurs worldwide. Dogs could develop infections that range from asymptomatic to severe, and shed leptospires with their urin. The aim of this study was to compare the results of real-time polymerase chain reaction (qPCR) by examining urine samples, and serological examination of the blood of stray dogs by the microscopic agglutination test (MAT) on ten serovars of Leptospira spp. A total of 100 blood samples and 50 urine samples of clinically healthy stray dogs were collected from June to November 2024 in the Banja Luka region of Bosnia and Herzegovina. Positive MAT titres (≥ 100) were detected in 15,0 % (15/100) of samples. Dogs were most commonly reactive to Australis (60,0 %) followed by Pomona (26,67 %) Bratislava (20.0 %), Canicola (13,33 %) and 6,67 % for Icterohaemorrhagiae, Grippotyphosa and Sejroe serovars. A positive result of the qPCR test was found in 11 (22.0 %) dogs, with only one of these dogs was positive in the MAT test. It has been found that MAT is not a good method for identifying dogs that shed leptospires in their urine. The study indicates a significant prevalence of leptospirosis in clinically healthy dogs. Therefore, it is important to implement appropriate control measures to prevent further spread of the disease in both human and animal populations.</p>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":" ","pages":"107759"},"PeriodicalIF":2.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758921","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}

{"title":"Bridging the predictive divide: A hybrid early warning system for scalable and real-time dengue surveillance in LMICs.","authors":"Dang Anh Tuan, Pham Vu Nhat Uyen","doi":"10.1016/j.actatropica.2025.107765","DOIUrl":"10.1016/j.actatropica.2025.107765","url":null,"abstract":"<p><p>The global resurgence of dengue presents an ongoing challenge for public health systems, particularly in low- and middle-income countries (LMICs) where conventional early warning systems (EWS) often suffer from reporting delays and under-detection. While AI-powered EWS offer superior accuracy, their reliance on dense data streams and advanced infrastructure limits their scalability in resource-limited contexts. This paper introduces a hybrid EWS architecture that strategically combines retrospective epidemiological data with selective real-time signals-such as climate variables and digital trends-within a modular machine learning framework. Drawing on case studies from Brazil, Malaysia, and Vietnam, we demonstrate how this architecture adapts to diverse data environments: integrating seroprevalence data to correct underreporting, enhancing zoning-based alerts with behavioral signals, and using climate predictors to overcome data fragmentation. Simulation results indicate that the hybrid model reduces outbreak response time from 7 to 14 days (traditional EWS) to 3-5 days and improves prediction accuracy to 85-90 %. These findings highlight the hybrid EWS as a context-sensitive, scalable solution that balances predictive performance with implementation feasibility-offering a viable pathway for LMICs to operationalize real-time dengue surveillance and proactive vector control.</p>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":" ","pages":"107765"},"PeriodicalIF":2.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144774489","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}

{"title":"Mitochondrial dynamics and description of a novel Myxobolus species infecting Piaractus mesopotamicus in Brazil.","authors":"Kassia R H Capodifoglio, Fernanda Schneberger, Antonio A M Maia, Maria J T Ranzani-Paiva","doi":"10.1016/j.actatropica.2025.107767","DOIUrl":"10.1016/j.actatropica.2025.107767","url":null,"abstract":"<p><p>A new Myxobolus species was identified infecting the gill arch of Piaractus mesopotamicus from a fish farm in São Paulo State, Brazil, and is described based on morphological, molecular, and biological data. Mature myxospores of Myxobolus naldonensis n.sp. were round in frontal view, with a length of 9.0 ± 0.3 µm, a width of 5.9 ± 0.3 µm, and a thickness of 5.2 ± 0.1 µm in the lateral view. Its polar capsules were elongated and equal size, occupying more than half of the myxospore, measuring 4.4 ± 0.2 µm in length, 1.7 ± 0.1 µm in width, and the polar tubules had 5 - 7 coils. Ultrastructural analysis revealed that the plasmodial wall was composed of a single membrane and that the sporogenesis process was asynchronous, with early developmental stages of myxospores in the periphery of the plasmodia and mature myxospores in the central part. Numerous mitochondria and pinocytotic channels were observed in the ectoplasm. Confocal analysis showed labeling of the nuclei of the sporoplasm, as well as of the valves and polar capsules. In mature myxospores a volume mitochondrial could be detected, but no labeling indicative of mitochondrial activity was observed. Molecular analysis based on the amplification and sequencing of small subunit ribosomal DNA (SSU rDNA) resulted in a 1968 bp sequence. Phylogenetic analysis grouped Myxobolus naldonensis n. sp. as sister species of Myxobolus tambaquiensis, which infects Colossoma macropomum, a fish belonging to the family Serrasalmidae.</p>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":" ","pages":"107767"},"PeriodicalIF":2.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144783227","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}

{"title":"Seasonal variation in wing morphometry of the stable fly Stomoxys calcitrans (Diptera: Muscidae) in Thailand: Climatic effects on phenotypic traits","authors":"Wirada Chapoopuang ,&nbsp;Supanat Jai-oun ,&nbsp;Kachamon Gulmala ,&nbsp;Pichit Panpongsith ,&nbsp;Piramon Suankaew ,&nbsp;Phutapat Ratanapisutpun ,&nbsp;Thekhawet Weluwanarak ,&nbsp;Tanawat Chaiphongpachara ,&nbsp;Tanasak Changbunjong","doi":"10.1016/j.actatropica.2025.107813","DOIUrl":"10.1016/j.actatropica.2025.107813","url":null,"abstract":"<div><div>The stable fly <em>Stomoxys calcitrans</em> (Linnaeus, 1758) (Diptera: Muscidae) is a globally significant mechanical vector of medical and veterinary importance. Understanding morphological variation offers insight into environmental influences on development, dispersal, and population structure in insects such as the stable fly. This study aimed to investigate how seasonal and climatic variations affect wing size and shape in <em>S. calcitrans</em>, as these traits are closely associated with biological functions including flight performance, host-seeking behavior, and vectorial capacity. Wing size and shape variation were examined across three geographically distinct sites in Thailand using geometric morphometrics, followed by multiple linear regression analysis to evaluate the influence of climatic variables on size, and a two-block partial least squares analysis to assess their influence on shape. Overall, <em>S. calcitrans</em> exhibited significantly larger wing size during the cool season compared to the hot and rainy seasons, particularly in females (<em>p &lt;</em> 0.05); no significant seasonal differences were observed in males based on pooled data (<em>p</em> &gt; 0.05). Regression estimates revealed significant sex-specific responses to climatic variables (<em>p &lt;</em> 0.05): male wing size decreased with increasing temperature and wind speed, whereas female wing size declined with temperature and rainfall but increased with relative humidity. Mahalanobis distance analysis confirmed significant seasonal effects on wing shape in both sexes, with the most pronounced differences occurring between the cool and rainy seasons. Wing shape variability also showed sex-specific climatic associations: in males, no climatic variables were significantly associated with wing shape (<em>p</em> &gt; 0.05), whereas in females, wing shape was associated with wind speed (<em>p</em> &lt; 0.05). These findings demonstrate the wing morphometric responses of <em>S. calcitrans</em> to seasonal and climatic influences, offering important insights into the environmental drivers of phenotypic variation and their potential implications for dispersal, population structure, and vector management strategies.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"270 ","pages":"Article 107813"},"PeriodicalIF":2.5,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932617","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}

{"title":"Macrophages activate fibroblasts to promote the collagen capsule formation during Trichinella spiralis infection","authors":"Zi Fang Zhang ,&nbsp;Yi Xuan Wang ,&nbsp;Yue Chun Tang,&nbsp;Meng Ying Gao,&nbsp;Ruo Qi Wang,&nbsp;Li Wang,&nbsp;Ying Ying Wei,&nbsp;Yi Jie Li,&nbsp;Peng Jiang","doi":"10.1016/j.actatropica.2025.107814","DOIUrl":"10.1016/j.actatropica.2025.107814","url":null,"abstract":"<div><div><em>Trichinella spiralis</em> (<em>T. spiralis</em>) can establish long-term infections within skeletal muscle cells, which are encapsulated by collagen capsule. Histological studies reveal that <em>T. spiralis</em>-infected muscle cells are surrounded by a significant number of inflammatory cells during the formation of collagen capsules. However, research has focused minimally on the role of inflammation in this process. In this study, mice were orally administered 300 muscle larvae per mouse and were euthanized weekly. The skeletal muscle was harvested. The quantity of macrophages, collagen deposition and the activated state of fibroblasts in the <em>T. spiralis</em>-infected muscle tissue were investigated using Masson’s trichrome staining, immunohistochemistry staining and western blot analysis. The macrophages were co-cultured with fibroblasts. Western blot analysis was conducted to confirm the type I collagen expression of fibroblasts. Then, the collagen deposition and activation status of fibroblasts were further confirmed through macrophage depletion in the infected muscle. The findings demonstrated that the expression levels of type I and IV collagen in the <em>T. spiralis</em>-infected muscle increased. Histological analyses showed a substantial presence of non-parenchymal cells embedded in areas of type I collagen deposition surrounding the infected muscle cells. These non-parenchymal cells included α-SMA⁺ myofibroblasts and CD206⁺macrophages. Type I collagen expression in fibroblasts increased when they were co-cultured with macrophages. Specific deletion of macrophages in the infected muscle resulted in reduced collagen deposition and a decreased number of α-SMA⁺myofibroblasts. These findings reveal that macrophages can regulate the activation of fibroblasts in the <em>T. spiralis</em>-infected muscle, leading to the production of type I collagen that constitutes the collagen capsule.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"270 ","pages":"Article 107814"},"PeriodicalIF":2.5,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144938389","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}

{"title":"Recombinant vaccinia virus expressing MIC8, AMA1, or RON4 induce protection against Toxoplasma gondii ME49 strain infection","authors":"Hae-Ji Kang ,&nbsp;Fu-Shi Quan","doi":"10.1016/j.actatropica.2025.107812","DOIUrl":"10.1016/j.actatropica.2025.107812","url":null,"abstract":"<div><div><em>Toxoplasma gondii</em> (<em>T. gondii</em>) infection is a globally prevalent and potentially severe disease, particularly in infants and immunocompromised individuals. Despite its widespread impact, no licensed vaccine is currently available for human use. The <em>T. gondii</em> antigens MIC8, AMA1, and RON4 have been identified as candidates capable of inducing immunity against toxoplasmosis. In this study, we generated recombinant vaccinia viruses (rVV) expressing MIC8 (MIC8-rVV), AMA1 (AMA1-rVV), or RON4 (RON4-rVV), and evaluated the vaccine efficacy of each rVV in mice. Mice were intranasally immunized twice with rVV and subsequently challenged with <em>T. gondii</em> ME49 strain. All three rVV vaccines induced <em>T. gondii-</em>specific immunoglobulin (Ig)G and IgA responses, as well as significant activation of CD8⁺ T cells and total B cells. All immunized mice 100% survived a lethal challenge, whereas the naïve control group did not. Among the three vaccines, MIC8-rVV elicited the strongest CD8⁺ T cell and B cell responses, resulting in the highest reduction in brain cyst counts following <em>T. gondii</em> ME49 strain challenge. These findings demonstrate that rVV-based delivery of MIC8, AMA1, and RON4 antigens can confer protective immunity against <em>T. gondii</em> ME49 strain infection, with MIC8 emerging as a particularly promising vaccine candidate.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"270 ","pages":"Article 107812"},"PeriodicalIF":2.5,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144938484","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}

{"title":"Hard ticks (Acari: Ixodidae) associated with resident and neotropical migratory wild birds in Colombian tropical rainforests with detection of Rickettsia species","authors":"Estefani T. Martínez-Sánchez ,&nbsp;Johnathan Alvarez‑Londoño ,&nbsp;Daniel Moreno-López ,&nbsp;Héctor E. Ramírez-Chaves ,&nbsp;Gabriel J. Castaño-Villa ,&nbsp;Fredy A. Rivera‑Páez","doi":"10.1016/j.actatropica.2025.107811","DOIUrl":"10.1016/j.actatropica.2025.107811","url":null,"abstract":"<div><div>The tropical rainforest is one of the most biodiverse, productive, and complex terrestrial biomes in the world. Human-induced environmental changes increase the emergence and spread of vector-borne diseases. Ticks (Acari: Ixodida) are medically and veterinary important arthropods that infest a wide range of vertebrate hosts, including humans, and act as vectors of diverse pathogens, such as bacteria of the genus <em>Rickettsia</em>. The aim of this study was to identify ticks and <em>Rickettsia</em> associated with resident and migratory Neotropical wild birds in tropical rainforests in the Andean region of Colombia. Ticks collected from wild birds were identified morphologically and molecularly, and <em>Rickettsia</em> detection was performed by PCR through the amplification of fragments of the <em>gltA</em> and <em>ompB</em> genes. A total of 189 ticks belonging to seven species of <em>Amblyomma</em> (six species) and <em>Ixodes</em> (one species) were identified, associated with 17 species of resident birds and two species of Neotropical migratory birds. We detected ‘<em>Candidatus</em> Rickettsia andeanae’ in the tick <em>Amblyomma longirostre</em>. We documented Neotropical migratory birds parasitized by ticks during the fall and spring migrations. This information is valuable for understanding bird–tick–<em>Rickettsia</em> associations in the tropical rainforests of Colombia.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"270 ","pages":"Article 107811"},"PeriodicalIF":2.5,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932615","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}

{"title":"A 3-year entomological cluster randomised controlled trial to assess the efficacy of mass-trapping for Aedes albopictus control in France: The vectrap project","authors":"Paulina A. Pontifes ,&nbsp;Nicolas Le Doeuff ,&nbsp;Yvon Perrin ,&nbsp;Cyrille Czeher ,&nbsp;Jean-Baptiste Ferré ,&nbsp;Yves Rozier ,&nbsp;Remi Foussadier ,&nbsp;Gregory L’Ambert ,&nbsp;David Roiz","doi":"10.1016/j.actatropica.2025.107810","DOIUrl":"10.1016/j.actatropica.2025.107810","url":null,"abstract":"<div><div>The Asian tiger mosquito, <em>Aedes albopictus,</em> is a significant public health threat due to its ability to spread diseases such as dengue and chikungunya. Traditional insecticide-based control methods are increasingly ineffective due to mosquito resistance and environmental concerns. This has driven interest in alternative strategies like mass trapping, although its effectiveness in reducing <em>Ae. albopictus</em> populations at the community level remains unclear. This study aimed to evaluate a mass trapping intervention over three years in six peri‑urban communities in France, using a Cluster Randomized Controlled Trial (CRCT) design. The intervention combined passive oviposition and host-seeking traps with source reduction and larviciding in the first two years. In the third year, control shifted to a community-based approach, with residents maintaining traps and managing breeding sites.</div><div>Mass trapping reduced mosquito abundance by 36–64 % in some communities, though efficacy varied due to local conditions, trap density, and implementation differences. The highest reductions occurred with high trap density and house coverage. The third year revealed challenges in sustaining community participation, impacting overall effectiveness.</div><div>This study provides valuable insights into the practical application of mass trapping, emphasizing the need for tailored approaches adapted to local contexts.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"270 ","pages":"Article 107810"},"PeriodicalIF":2.5,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932688","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}

{"title":"Widespread infections with bacterial and protozoan tick-borne pathogens in 22 wildlife species across South African game reserves","authors":"Carlo Andrea Cossu ,&nbsp;Melvyn Quan ,&nbsp;Nicola Collins ,&nbsp;Jeanette Wentzel ,&nbsp;Lin-Mari de Klerk ,&nbsp;Louis Ockert van Schalkwyk ,&nbsp;Ilse Vorster ,&nbsp;Marinda C. Oosthuizen ,&nbsp;L. Neves ,&nbsp;Raksha Vasantrai Bhoora ,&nbsp;Henriette van Heerden","doi":"10.1016/j.actatropica.2025.107807","DOIUrl":"10.1016/j.actatropica.2025.107807","url":null,"abstract":"<div><div>Tick-borne pathogens (TBPs) are a growing global concern, contributing to emerging and re-emerging diseases in humans and animals. Human encroachment into natural habitats and unregulated wildlife translocations are key drivers of TBP emergence, as they expand wildlife–livestock–human interfaces and facilitate the introduction of alien TBPs into naïve hosts and new regions. Accurate molecular surveillance is essential to guide management strategies and prevent clinical outbreaks.</div><div>This study conducted a cross-sectional molecular screening of TBPs in wildlife from 22 host species sampled over a four year period from 2021 to 2024 across eight South African protected areas: Kruger (KNP), Karoo (KaNP), Camdeboo (CaNP), Mountain Zebra (MZNP), Mokala (MokNP), and Addo Elephant (AENP) National Parks, as well as Lapalala Wilderness (LWR), and Timbavati (TPNR) Nature Reserves. A total of 572 spleen, liver and blood samples were tested for <em>Anaplasma, Ehrlichia, Rickettsia, Coxiella, Theileria</em> and <em>Babesia</em> spp. using Reverse Line Blot hybridization, with confirmation by Sanger sequencing and phylogenetic analysis. Prevalence, confidence intervals, risk factors and co-infections were also assessed.</div><div>High prevalence (50–100 %) of <em>Anaplasma/Ehrlichia</em> and <em>Theileria/Babesia</em> spp. was recorded. <em>Anaplasma marginale</em> was detected in African buffalo (<em>Syncerus caffer</em>; KNP), kudu (<em>Tragelaphus strepsiceros</em>; CaNP), warthog (<em>Phacochoerus africanus</em>; AENP), hippo (<em>Hippopotamus amphibius</em>; TPNR), and eland (<em>Taurotragus oryx</em>; KaNP), while zoonotic <em>A. capra</em> was found in a hippo. <em>Coxiella burnetii</em> was detected in all sampled areas and in multiple species, including African buffalo, wild dog (<em>Lycaon pictus</em>), black wildebeest (<em>Connochaetes gnou</em>), eland, gemsbok (<em>Oryx gazella</em>), zebra (<em>Equus quagga</em>), hartebeest (<em>Alcelaphus buselaphus</em>), springbok (<em>Antidorcas marsupialis</em>), and warthog. SFG <em>Rickettsia</em> spp., including <em>R. africae</em> and <em>R. felis</em>, were detected in 18 animals. <em>Babesia bigemina</em> was found in springbok (MokNP).</div><div>These findings reveal widespread TBP presence in South African wildlife and highlight the need for ongoing surveillance to mitigate spillover risks and protect ecosystems and public health. While high prevalences were observed, clinical impacts of these infections on wildlife remain unclear.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"270 ","pages":"Article 107807"},"PeriodicalIF":2.5,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144938504","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}

{"title":"Opisthorchis viverrini Helminth Defense Molecule: Structural features, molecular interactions, and dual immunomodulatory roles","authors":"Muhammad Fikri Heikal ,&nbsp;Kamonrut Kongpha ,&nbsp;Alok Kafle ,&nbsp;Jan Clyden Tenorio ,&nbsp;Sujittra Chaiyadet ,&nbsp;Panupong Mahalapbutr ,&nbsp;Kampeebhorn Boonloh ,&nbsp;Krajang Talabnin ,&nbsp;Thewarach Laha ,&nbsp;Prasert Saichua ,&nbsp;Sutas Suttiprapa","doi":"10.1016/j.actatropica.2025.107809","DOIUrl":"10.1016/j.actatropica.2025.107809","url":null,"abstract":"<div><div>The liver fluke <em>Opisthorchis viverrini</em> causes chronic infections in humans and animals. This helminth is known to coexist with the bacterial microbiome in the host's bile duct, and their interaction potentially impacts the helminth’s pathogenicity. While most infected individuals remain asymptomatic, the mechanism of immune modulation remains unclear. The immunomodulatory protein Helminth Defense Molecule (HDM) has been characterized in other liver fluke species; however, its functional role exhibits distinct variations. This study aims to uncover the structural properties and biological function of HDM from <em>O.viverrini</em> (OvHDM). Using bioinformatics tools, we predicted the protein structure, analyzed its physicochemical properties, and potential molecular interactions. Furthermore, the structural and molecular interactions were experimentally confirmed by Circular Dichroism (CD) Spectroscopy. For functional analysis, RAW 264.7 macrophage cells were treated with <em>Escherichia coli</em> LPS pre-incubated with synthetic OvHDM peptides, followed by TNF and IL-6 levels quantification using ELISA. The predicted structure of OvHDM predominantly consists of α-helices configuration, resembling the antimicrobial peptide LL-37. It exhibits a high distribution of positive amino acids, strong stability under physiological conditions, and potential functional sites in both the N- and C-terminal domains. OvHDM demonstrated stronger interactions with LPS compared to the FhHDM-1 P2 as a control. The CD spectroscopy showed secondary structure dynamics of HDMs synthetic peptides upon LPS addition. Finally, synthetic OvHDM peptides were shown to both reduced LPS-induced cytokine production <em>in vitro</em>, and independently induced IL-6 production. These findings highlight the dual immunomodulatory activity of OvHDM, suggesting its role in fine-tuning the host immune environment during infection.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"270 ","pages":"Article 107809"},"PeriodicalIF":2.5,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932616","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}