Acta tropica最新文献

{"title":"EBV and CMV DNAemia across surgical, nephrological and neurological cohorts","authors":"Adnan A. Mubaraki ,&nbsp;Abdullah S. Alqahtani ,&nbsp;Anas A. Alshamrani ,&nbsp;Hussain R. Barnawi ,&nbsp;Mohammed M. Algethami ,&nbsp;Mohammed A Alabdalli ,&nbsp;Ahmed N. Alghamdi ,&nbsp;Naifa Alenazi ,&nbsp;Ahmed S. Abdel-Moneim","doi":"10.1016/j.actatropica.2025.107953","DOIUrl":"10.1016/j.actatropica.2025.107953","url":null,"abstract":"<div><h3>Background</h3><div>Epstein–Barr virus (EBV) and cytomegalovirus (CMV) are common herpesviruses implicated in various diseases. This study aimed to assess the prevalence of EBV and CMV DNAemia across diverse medical conditions, including neurological disorders.</div></div><div><h3>Methods</h3><div>This study comprised a retrospective cohort including 2463 patients with various medical conditions screened for either CMV (<em>n</em> = 2090) or EBV (<em>n</em> = 373) using quantitative PCR (qPCR) between 2020 and 2024. Additionally, it also included prospective cohort of 119 patients with diverse neurological disorders who were screened for CMV and EBV by qPCR. Data was analyzed to assess EBV and CMV DNAemia and associations with demographic and clinical factors.</div></div><div><h3>Results</h3><div>EBV DNAemia was detected in 57/373 patients (15.3 %), significantly associated with age (<em>p</em> = 0.032) and clinical category (<em>p</em> &lt; 0.001). Highest positivity was observed in surgical patients (46.9 %) and children &lt;12 years (31.6 %). Viral loads were predominantly low to moderate, with high-level DNAemia in 28.1 % of cases. CMV DNAemia was found in 239/2090 patients (11.4 %), clustered by clinical category (<em>p</em> &lt; 0.001), with highest absolute numbers among “Other” (55.2 %) and nephrology patients (30.5 %). Low-level CMV DNAemia predominated (70 %), high-level replication was rare (4.5 %), and age or sex were not significant predictors. In the neurological cohort, EBV or CMV was detected in 7/119 cases (5.9 %), all low-level, with no significant associations with age, sex, or diagnosis.</div></div><div><h3>Conclusion</h3><div>EBV and CMV infections were infrequent but showed selective distribution in certain clinical subgroups, particularly paediatric, surgical, and nephrology patients. Limited evidence of EBV/CMV involvement was observed in specific neurological disorders.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107953"},"PeriodicalIF":2.5,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145809211","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":"Pathogen assessment of Galapagos landbirds reveals novel herpesviruses and adenoviruses","authors":"Ainoa Nieto-Claudin ,&nbsp;Courtney L. Pike ,&nbsp;Gislayne Mendoza-Alcívar ,&nbsp;Birgit Fessl ,&nbsp;David J. Anchundia ,&nbsp;Sharon L. Deem ,&nbsp;Paula A. Castaño ,&nbsp;Kathleen Apakupakul ,&nbsp;Roland Digby ,&nbsp;Carlos Sacristán","doi":"10.1016/j.actatropica.2025.107955","DOIUrl":"10.1016/j.actatropica.2025.107955","url":null,"abstract":"<div><div>Galapagos landbirds are currently threatened due to the negative effects of human encroachment. At least one species has become extinct, and several have been extirpated or suffered severe population declines in the past decades. Although some avian pathogens have been described over the years, the presence and prevalence of several infectious agents that may severely impact on the health and conservation of wild and domestic birds in the archipelago remain understudied. To fill this gap, we conducted a comprehensive health assessment of Galapagos landbirds covering five islands (including protected and anthropized areas), testing for three pathogens of avian conservation concern: adenoviruses (AdV), herpesviruses (HV), and <em>Mycoplasma</em> spp. Oral and cloacal swabs of 421 landbirds from 14 species were tested by PCR, and positive samples were subjected to Sanger sequencing. None of the samples were positive for <em>Mycoplasma</em> spp. A total of 35 birds (8.31 %) tested positive for AdV, while 13 (3.09 %) were positive for HV, with higher prevalences found within the inhabited islands of Floreana and Santa Cruz, respectively. Seven main AdV nucleotide sequence types (STs) were obtained, with AdV-1, AdV-3 and AdV-5 clustering within the genus <em>Barthadenovirus</em>, and AdV-2, AdV-4, AdV-6 and AdV-7 grouping within the genus <em>Aviadenovirus.</em> Three HV STs were obtained, with HV-1 and HV-3 clustering within the genus <em>Mardivirus</em>, and HV-2 grouping within the genus <em>Iltovirus</em>. To our knowledge, this is the first molecular description of novel adenoviruses and herpesviruses in Galapagos landbirds, which will inform current and future conservation efforts in the archipelago.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107955"},"PeriodicalIF":2.5,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145809371","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":"“Proteome-wide immunoinformatics analysis of Leishmania major: discovery of eight novel vaccine candidates and systematic evaluation of historical targets”","authors":"Ali Abdulqader,&nbsp;Farah M. Abdulsada,&nbsp;Mariam Qassim Al-Dulemey,&nbsp;Mohd Shahir Shamsir","doi":"10.1016/j.actatropica.2025.107949","DOIUrl":"10.1016/j.actatropica.2025.107949","url":null,"abstract":"<div><div><em>Leishmania major</em> remains a significant public health threat, yet vaccine development has been hampered by fragmented antigen selection approaches and limited systematic proteome-wide analysis. In this study, we developed a comprehensive immunoinformatics pipeline to systematically evaluate the entire L. <em>major</em> proteome (8038 proteins) using standardized selection criteria: subcellular localization (extracellular/membrane), antigenicity (VaxiJen ≥ 0.5), allergenicity assessment (AllerTOP/AlgPred consensus), signal peptide presence (SignalP ≥ 0.7), transmembrane topology (TMHs &lt; 2), optimal sequence length (100–500 aa), host homology exclusion (≤ 30% identity), and cross-species conservation analysis. This rigorous screening identified nine potential vaccine targets, including eight novel candidates and the well-known established antigen GP46 (Q4Q6B6) that passed all filtering criteria. Remarkably, four candidates (E9AFZ7, Q4Q0L6, Q4Q0X3, Q4QC59) remain annotated as \"uncharacterized proteins\" in UniProt, representing completely unexplored therapeutic targets. All nine candidates exhibited optimal vaccine properties: membrane/extracellular localization, high antigenicity (VaxiJen 0.52–0.89), non-allergenicity, signal peptide presence, and absence of human homologs. To validate our pipeline's stringency, we retrospectively analyzed twelve historically proposed L. <em>major</em> vaccine candidates using identical criteria. Strikingly, 67% (8/12) failed our selection standards: eight due to concerning host homology (&gt; 30% human identity) and four due to predicted allergenicity, with only GP46 meeting all requirements. Cross-species conservation analysis demonstrated broad <em>Leishmania</em> species coverage for our novel candidates, supporting their potential as universal vaccine targets. This study represents a paradigm shift from focusing on individual known antigens to employing systematic proteome-wide discovery, delivering a standardized framework for <em>Leishmania</em> vaccine candidate selection. The identification of nine candidates including GP46 antigen, including four uncharacterized proteins, significantly expands the therapeutic pipeline while our validation approach establishes quality-control standards essential for advancing neglected tropical disease vaccine development.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107949"},"PeriodicalIF":2.5,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145800339","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":"Evidence of eurythermal behavior and microbiota differentiation in Aedes aegypti and Aedes albopictus from the Colombian Amazon biome","authors":"Alejandro Castañeda Espinosa,&nbsp;Rafael J. Vivero Gómez,&nbsp;Daniela Duque-Granda,&nbsp;Gloria E. Cadavid-Restrepo,&nbsp;Howard Junca,&nbsp;Claudia Ximena Moreno-Herrera","doi":"10.1016/j.actatropica.2025.107951","DOIUrl":"10.1016/j.actatropica.2025.107951","url":null,"abstract":"<div><div>Temperature is one of the most important factors influencing mosquito development, vector competence, and microbiome composition, affecting the disease transmission cycle by either facilitating or inhibiting pathogen establishment. This study aimed to estimate temperature preference and its correlation with bacterial communities in populations of <em>Ae. aegypti</em> and <em>Ae. albopictus</em> from the urban area of Leticia, Amazonas. Temperature preference profiles were obtained by introducing 50 individuals of each species and sex in six replicates for one hour into a device with a temperature gradient of 19–36 °C. Subsequently, a metataxonomic analysis of bacterial communities was performed using DNA extracted from whole mosquito body groups associated with temperature ranges defined by their statistical significance. First, it was determined that females of both species preferred temperatures between 23 and 28 °C. Meanwhile, <em>Ae. aegypti</em> males showed a larger temperature preference range (21–28 °C) than <em>Ae. albopictus</em> males (25–28 °C). Regarding bacterial communities, an increase in diversity was observed in males of both species with rising temperatures, whereas the opposite occurred in females. The Amplicon Sequence Variants (ASVs) associated with <em>Asaia</em> (2.88%), <em>Cedecea</em> (45.80%), <em>Elizabethkingia</em> (77.78%), and <em>Klebsiella</em> (8.90%) were the most abundant genera in <em>Ae. aegypti</em>. In comparison, <em>Ae. albopictus</em> exhibited a high abundance of <em>Elizabethkingia</em> (36.34%), <em>Pseudomonas</em> (95.08%), and <em>Wolbachia</em> (12.73%). Interestingly, <em>Elizabethkingia</em> varied in abundance according to sex and temperature in both species. It was determined that the structure of <em>Aedes</em> bacterial communities in the Amazon was influenced by sex, species, and temperature, indicating high plasticity and ubiquity according to temperature profiles.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107951"},"PeriodicalIF":2.5,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145800382","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":"Finding the hidden genes in Leishmania guyanensis genome: Application of proteogenomics approach to improve the genome annotation in the kinetoplastid parasite","authors":"Shubhankar A Pawar ,&nbsp;Aditi Shenoy ,&nbsp;Karthick Vasudevan ,&nbsp;Nalini Mishra ,&nbsp;Mahendra Jamdhade ,&nbsp;Harsh Pawar","doi":"10.1016/j.actatropica.2025.107952","DOIUrl":"10.1016/j.actatropica.2025.107952","url":null,"abstract":"<div><div>The kinetoplastid protozoan parasite <em>Leishmania guyanensis</em> a member of the <em>Leishmania</em> (<em>Viannia</em>) species complex is the causative agent of American tegumentary leishmaniasis (ATL). <em>L. guyanensis</em> infections typically result in cutaneous lesions, but in some cases can progress to mucocutaneous leishmaniasis, particularly when co-infected with <em>Leishmania</em> RNA virus 1 (LRV1), thus leading to exacerbated inflammation, treatment failure, and relapse. Despite the availability of its reference genome, limitations in gene annotation persist due to the presence of hypothetical proteins, pseudogenes, and unrecognised coding regions. In this study, we employed a proteogenomic approach integrating publicly available high-resolution mass spectrometry data with a custom six-frame translated genome database to refine the genome annotation of <em>L. guyanensis</em> strain MHOM/BR/75/M4147. Utilising stringent database-dependent searches with a 1% false discovery rate, we identified numerous unique peptides, of which 653 were genome search-specific peptides (GSSPs) mapping exclusively to unannotated genomic regions. These GSSPs facilitated the discovery of 65 novel protein-coding genes and the correction of 62 existing gene models, including N- and C-terminal extensions. Our findings demonstrate the power of proteogenomics to uncover cryptic protein-coding regions and improve genome annotations beyond conventional predictions. This refined annotation enhances our understanding of <em>L. guyanensis</em> biology, providing a more accurate proteomic landscape that can inform studies on parasite virulence, host interaction, and potential therapeutic targets. The study underscores the importance of integrating proteomic evidence with genomic data to capture the full coding potential of kinetoplastid parasites, paving the way for improved diagnostics and interventions against leishmaniasis.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107952"},"PeriodicalIF":2.5,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145800375","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":"Surface ultrastructure and lodging of Entamoeba histolytica and Giardia lamblia cysts on fruits and vegetables","authors":"Ernesto Ramírez-Moreno ,&nbsp;Keity J. Farfán-Pira ,&nbsp;Nancy Rivas ,&nbsp;Ricardo Alejandre-Aguilar ,&nbsp;Alberto Antonio-Campos","doi":"10.1016/j.actatropica.2025.107950","DOIUrl":"10.1016/j.actatropica.2025.107950","url":null,"abstract":"<div><div>Intestinal protozoan infections remain a global public health concern, particularly when transmitted through contaminated fruits and vegetables. This study investigated whether surface ultrastructures of selected produce create favorable microenvironments for cyst lodging of <em>Entamoeba histolytica</em> and <em>Giardia lamblia</em>. Scanning electron microscopy (SEM) was used to examine <em>Fragaria × ananassa, Coriandrum sativum, Solanum lycopersicum</em>, and <em>Lactuca sativa</em>. Plant surfaces exhibit distinct irregularities, including cavities, crevices, and vein-associated folds, which provide protective sites for cyst retention. Cysts were frequently observed within seed-associated cavities of <em>F. × ananassa</em>, along vein-associated and stomatal depressions in <em>C. sativum</em>, and within surface pits of <em>S. lycopersicum</em>. In <em>L. sativa</em>, the number of cavities did not differ significantly between outer and intermediate leaves (10–12 cavities/100 μm²), whereas inner leaves displayed significantly higher cavity densities (14–18 cavities/100 μm²; <em>p</em> &lt; 0.008), and cysts were commonly found lodged within cavities of the inner leaf, as well as within folds and surface irregularities of the outer leaves. These findings demonstrate that microscopic features of plant surfaces facilitate protozoan persistence, thereby contributing to foodborne transmission. Understanding these interactions underscores the need for improved agricultural handling, food processing strategies, and consumer level education to mitigate the risk of parasitic infections linked to fresh produce.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107950"},"PeriodicalIF":2.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145779745","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":"Chloroquine-resistant Plasmodium vivax malaria in Ethiopia: A systematic review and meta-analysis","authors":"Yenesew Mihret Wondmagegn ,&nbsp;Abebaw Setegn ,&nbsp;Getu Girmay ,&nbsp;Muluneh Assefa ,&nbsp;Banchayehu Getnet ,&nbsp;Tena Cherkos ,&nbsp;Wagaw Abebe ,&nbsp;Nega Dessie ,&nbsp;Adane Derso ,&nbsp;Zufan Yiheyis ,&nbsp;Adane Adugna ,&nbsp;Tadesse Misganaw ,&nbsp;Aberham Abere ,&nbsp;Mebratu Tamir ,&nbsp;Mekuriaw Belayneh ,&nbsp;Azanaw Amare ,&nbsp;Agenagnew Ashagre ,&nbsp;Birhanu Malede ,&nbsp;Gashaw Azanaw Amare","doi":"10.1016/j.actatropica.2025.107947","DOIUrl":"10.1016/j.actatropica.2025.107947","url":null,"abstract":"<div><div><em>Plasmodium vivax</em> accounts for about 40% of malaria cases in Ethiopia, where chloroquine remains the first-line treatment. However, the emergence of chloroquine resistance threatens the effectiveness of treatment. This systematic review synthesizes current evidence on chloroquine-resistant <em>Plasmodium vivax</em> in Ethiopia. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42024564745) and conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Comprehensive searches were performed in PubMed, Medline, EMBASE, Google Scholar, Web of Science, ScienceDirect, and African Journals Online. Data were extracted using Microsoft Excel and analyzed with STATA version 11. Random-effects models were used to estimate pooled prevalence with 95% confidence intervals. Heterogeneity was assessed using the I-squared statistic, and publication bias was evaluated using Egger’s test and a funnel plot. Thirteen studies with 2,190 participants reported a pooled prevalence of chloroquine-resistant <em>Plasmodium vivax</em> of 7.32% (95% CI: 2.55–12.08; I² = 95.1%, p &lt; 0.001). Resistance prevalence was higher in studies using both microscopy and PCR 7.32% (95% CI: 2.55–12.08), during the 2003–2009 study period 10.70% (95% CI: −1.24–22.65), and in the Oromia region 9.58% (95% CI: −0.41–19.58), while a 42-day follow-up reported a pooled prevalence of 17.91% (95% CI: −9.34–45.15). Chloroquine-resistant <em>Plasmodium vivax</em> is present in Ethiopia, with an overall prevalence of about 7%. Although resistance remains moderate, it is clinically significant and underscores the importance of ongoing surveillance, regular treatment monitoring, and consideration of alternative therapeutic approaches.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107947"},"PeriodicalIF":2.5,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145773077","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":"The dynamic of Trypanosoma cruzi transmissibility in field-caught Mepraia spinolai (Hemiptera: Reduviidae) of contrasting seasons: A developmental stage-dependent study","authors":"Nicol Quiroga ,&nbsp;Francisca Farías ,&nbsp;Angélica López ,&nbsp;Carezza Botto-Mahan ,&nbsp;Aldo Solari","doi":"10.1016/j.actatropica.2025.107948","DOIUrl":"10.1016/j.actatropica.2025.107948","url":null,"abstract":"<div><div>A competent vector can harbor a pathogen and infect a high number of hosts. Scarce information is available on how triatomine vectors accomplish this task in nature, particularly without knowing the number of parasites they excrete. We study the dynamics of <em>Trypanosoma cruzi</em> transmissibility in the triatomine <em>Mepraia spinolai</em> collected in summer (December 2018) and winter (July 2019) of an austral endemic area. The insects received two feedings in the laboratory, the day after arrival and 45 days after the first feeding. Excreta samples were collected, DNA was extracted, and parasite loads were quantified by qPCR. After feeding, the parasite loads of the first and second excreta samples revealed differences between summer and winter insects. Overall, parasite load reductions and increases were detected in summer (51.2% and 32.5%) and in winter (9.1% and 15.2%) infected insects. The number of times the parasite load was reduced in summer insects revealed that early stage nymphs accomplished it at the highest ratio (× 740), middle stage nymphs (× 14), and late developmental stages with the lowest ratio (× 6.7). Therefore, fifth instar nymphs and adults have the maximal capacity to harbor <em>T. cruzi</em>, and those with the highest competence to transmit it, and early nymphs are the ones with minimal vectorial capacity. About 7% of the winter insects and 58.5% of the summer excreted quantifiable parasite loads right after collection. The amount of <em>T. cruzi</em> excreted in summer by <em>M. spinolai</em> reached medians between 950 and 2597 parasite equivalents/excreta, considering all developmental stages. Finally, molting during processes of <em>T. cruzi</em> load reduction and increase suggests that the exoskeleton shedding does not affect the excretion of <em>T. cruzi</em>.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107948"},"PeriodicalIF":2.5,"publicationDate":"2025-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145766738","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":"Susceptibility to the larvicide pyriproxyfen and genotyping of kdr mutations in two Aedes aegypti populations from Maranhão State, Brazil","authors":"Valéria Cristina Soares Pinheiro ,&nbsp;Juliete Lima Viana ,&nbsp;Joelma Soares da Silva ,&nbsp;Márcia Verônica Pereira Gonçalves ,&nbsp;Aylane Tamara dos Santos Andrade ,&nbsp;Luiz Paulo Brito ,&nbsp;Ademir Jesus Martins","doi":"10.1016/j.actatropica.2025.107946","DOIUrl":"10.1016/j.actatropica.2025.107946","url":null,"abstract":"<div><div><em>Aedes aegypti</em> is the main vector of arboviruses in the Americas, including dengue, Zika and chikungunya. In Brazil, initial control strategies relied on insecticides, but their continuous use has promoted resistance, mainly through metabolic changes and knockdown resistance (<em>kdr</em>) mutations, which are key molecular markers of pyrethroid resistance. This study evaluated the susceptibility of <em>Ae. aegypti</em> populations from Caxias and São Mateus (Maranhão State) to the larvicide pyriproxyfen and investigated the frequency of the <em>kdr</em> SNPs V410L, V1016I and F1534C. Eggs collected in the field were reared to the F1 generation, and L3 larvae were subjected to quantitative bioassays to determine emergence inhibition (EI) indexes. DNA extracted from adults was analyzed by qPCR to assess <em>kdr</em> allele frequencies. Bioassays showed 98 % mortality in Caxias and 100 % in São Mateus when exposed to 0.8 μg/mL of pyriproxyfen. EI₅₀ values were 0.094 mg/L and 0.083 mg/L, while EI₉₀ values reached 1.596 mg/L and 0.558 mg/L, respectively. Resistance ratios, relative to the Rockefeller strain, were 1.175 and 1.038, indicating susceptibility. Regarding <em>kdr</em> markers, we observed a predominance of the <em>kdr</em> R1 allele (VVC, mutated at site 1534) in Caxias (50 %) and of the <em>kdr</em> R2 allele (LIC, mutated at sites 410, 1016 and 1534) in São Mateus (53 %). The wild-type S allele (VVF, without mutations) showed frequencies of 47 % and 8 % in Caxias and São Mateus, respectively. Despite the presence of pyrethroid-resistant alleles, no phenotypic resistance to the IGR pyriproxyfen was observed. These results confirm the effectiveness of pyriproxyfen against <em>Ae. aegypti</em> in Maranhão, while the presence of <em>kdr</em> mutations underscores the need for ongoing surveillance and integrated management to prevent resistance.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107946"},"PeriodicalIF":2.5,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145761872","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":"Loss of tegumental papillae and spines during maturation of Clonorchis sinensis: Evidence from colchicine disruption","authors":"Eun-Min Kim","doi":"10.1016/j.actatropica.2025.107945","DOIUrl":"10.1016/j.actatropica.2025.107945","url":null,"abstract":"<div><div><em>Clonorchis sinensis</em> is a foodborne liver fluke and Group 1 carcinogen endemic to East Asia. Its syncytial tegument mediates host–parasite interactions and serves as the primary target of praziquantel (PZQ), which exhibits reduced efficacy against juvenile stages. This study investigated whether tegumental papillae and spines are truly lost or internalized during the maturation of <em>C. sinensis</em>, and employed colchicine as a diagnostic perturbation to probe for subtegumental remnants. Excysted metacercariae, juvenile worms (10 days postinfection), and adult worms (4 weeks postinfection) were examined using scanning electron microscopy; a subset of adults was treated with colchicine (1 µM, 37°C, 6 h). Tegumental spines were quantified per 100 µm² on calibrated images. Spine density declined from 36 ± 2 / 100 µm² in metacercariae to 6 ± 1 / 100 µm² in juveniles (Welch’s t-test, P &lt; 0.05) and was below quantifiable limits in adults (0–2 / 100 µm², qualitative). Colchicine-treated adults exhibited distal surface fragmentation without revealing hidden spines or papillae. These findings provide quantitative morphological evidence that papillae and spines are progressively lost, rather than internalized, during maturation of <em>C. sinensis</em>, thereby clarifying a key aspect of tegumental remodeling across developmental stages.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"273 ","pages":"Article 107945"},"PeriodicalIF":2.5,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145754985","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}