Pub Date : 2026-01-17DOI: 10.1016/j.actatropica.2026.107985
Nalia Mekarnia , Pénélope Gillard , Benjamin Aubry , Antoine Huguenin , Philippe M. Loiseau , Jérôme Depaquit
Cutaneous leishmaniasis (CL), a neglected disease prevalent in 88 countries, is commonly caused by Leishmania (L.) major in the Old World, posing significant public health concerns. Isolation from sand flies or infected mammals and in vitro cultivation of Leishmania parasites are critical for epidemiological studies, but these cultures are often compromised by bacterial and fungal contamination, especially when outsourced from vector digestive tracts. While the Leishmania parasite’s natural resistance to antibiotics simplifies bacterial control, most antifungals also inhibit the parasites growth, complicating efforts to manage fungal contamination. This study aimed to identify antifungal agents that could protect Leishmania cultures from yeast contamination with minimal impact on parasite growth. Five antifungal drugs: griseofulvin (GRF), caspofungin diacetate (CSF), 5-fluorocytosine (5-FC), po(ly)vidone-iodine (PVI), and undecylenic acid (UCA) were assessed in vitro for their effects on promastigote forms of L. major. The IC50 values indicated strong antileishmanial activity for 5-FC, GRF, UCA, and PVI (<13 µM), whereas CSF exhibited higher IC50 value (17 µM), suggesting relatively lower toxicity to the parasites. Under continuous CSF exposure, L. major promastigotes demonstrated substantial survival, with only a modest reduction in maximum parasite growth curves (peak of 2.65 × 10⁶ parasites/mL) compared to untreated controls (4.31 × 10⁶ parasites/mL maximum growth). These findings suggest that caspofungin diacetate could be used in the field to decontaminate Leishmania cultures from yeasts without significant parasite loss, facilitating L. major isolation and epidemiological investigations in endemic regions.
{"title":"Improving Leishmania isolation in field conditions: Efficacy of caspofungin against yeasts contamination","authors":"Nalia Mekarnia , Pénélope Gillard , Benjamin Aubry , Antoine Huguenin , Philippe M. Loiseau , Jérôme Depaquit","doi":"10.1016/j.actatropica.2026.107985","DOIUrl":"10.1016/j.actatropica.2026.107985","url":null,"abstract":"<div><div>Cutaneous leishmaniasis (CL), a neglected disease prevalent in 88 countries, is commonly caused by <em>Leishmania (L.) major</em> in the Old World, posing significant public health concerns. Isolation from sand flies or infected mammals and <em>in vitro</em> cultivation of <em>Leishmania</em> parasites are critical for epidemiological studies, but these cultures are often compromised by bacterial and fungal contamination, especially when outsourced from vector digestive tracts. While the <em>Leishmania</em> parasite’s natural resistance to antibiotics simplifies bacterial control, most antifungals also inhibit the parasites growth, complicating efforts to manage fungal contamination. This study aimed to identify antifungal agents that could protect <em>Leishmania</em> cultures from yeast contamination with minimal impact on parasite growth. Five antifungal drugs: griseofulvin (GRF), caspofungin diacetate (CSF), 5-fluorocytosine (5-FC), po(ly)vidone-iodine (PVI), and undecylenic acid (UCA) were assessed <em>in vitro</em> for their effects on promastigote forms of <em>L. major</em>. The IC<sub>50</sub> values indicated strong antileishmanial activity for 5-FC, GRF, UCA, and PVI (<13 µM), whereas CSF exhibited higher IC<sub>50</sub> value (17 µM), suggesting relatively lower toxicity to the parasites. Under continuous CSF exposure, <em>L. major</em> promastigotes demonstrated substantial survival, with only a modest reduction in maximum parasite growth curves (peak of 2.65 × 10⁶ parasites/mL) compared to untreated controls (4.31 × 10⁶ parasites/mL maximum growth). These findings suggest that caspofungin diacetate could be used in the field to decontaminate <em>Leishmania</em> cultures from yeasts without significant parasite loss, facilitating <em>L. major</em> isolation and epidemiological investigations in endemic regions.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"275 ","pages":"Article 107985"},"PeriodicalIF":2.5,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146002830","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 : 2026-01-17DOI: 10.1016/j.actatropica.2026.107984
Estefania Grostieta , Beatriz Salceda-Sánchez , Héctor M. Zazueta-Islas , Miguel Tenchipe-Márquez , Laura V. Mondragon-Peña , Joselin Benítez , Paola Yesenia García Castillo , Carlos I. Miranda-Caballero , Gabriela Aguilar-Tipacamú , Miguel A. Alonso-Diaz , Roger I. Rodríguez-Vivas , Jorge L. Chagoya- Fuentes , Edelmira Jácome-Sosa , Herón Huerta , Ingeborg Becker , Sokani Sánchez-Montes
For over 80 years, the genus Coxiella was considered monotypic, comprising only Coxiella burnetii, the aetiological agent of Q fever. Recent studies, however, have revealed several candidate species and genetic lineages associated with ticks, many of which act as endosymbionts that are essential for tick development. This association is particularly notable in the members of the Rhipicephalus sanguineus complex, where Candidatus Coxiella massiliensis (zoonotic) and Candidatus Coxiella mudrowiae (unknown pathogenicity) have been described. Given the close relationship between these ticks, domestic dogs, and humans, active surveillance for Coxiella species of medical and veterinary importance is crucial.
This study evaluated the presence and diversity of Coxiella species in 812 hard ticks: Amblyomma mixtum (n = 23), Rhipicephalus linnaei (n = 762), and R. sanguineus sensu stricto (n = 27) collected from December 2018 to November 2024 parasitizing dogs (n = 418), humans (n = 18), cattle (n = 4), and one cat across 17 states of Mexico.
A fragment (∼1500 base pair) of the Coxiella 16S ribosomal DNA (rDNA) gene was amplified, sequenced, and analysed phylogenetically. Additionally, published records of Coxiella endosymbionts associated with ticks parasitising dogs were compiled. Of 812 samples, 188 tested positive, revealing three Coxiella lineages closely related to known endosymbionts of Rhipicephalus and Amblyomma ticks. A review of 25 studies from across the globe identified four Coxiella taxa in 23 tick species from dogs across 19 countries. This is the first report of Coxiella lineages in dog-associated ticks in Mexico. Our findings expand the known diversity of the genus in the Neotropical region and underscore the need for further research to clarify their ecological roles and potential health implications.
{"title":"Molecular detection of Coxiella endosymbionts associated with ixodid ticks recovered from animals and man in Mexico: Phylogeography and haplotype diversity analysis","authors":"Estefania Grostieta , Beatriz Salceda-Sánchez , Héctor M. Zazueta-Islas , Miguel Tenchipe-Márquez , Laura V. Mondragon-Peña , Joselin Benítez , Paola Yesenia García Castillo , Carlos I. Miranda-Caballero , Gabriela Aguilar-Tipacamú , Miguel A. Alonso-Diaz , Roger I. Rodríguez-Vivas , Jorge L. Chagoya- Fuentes , Edelmira Jácome-Sosa , Herón Huerta , Ingeborg Becker , Sokani Sánchez-Montes","doi":"10.1016/j.actatropica.2026.107984","DOIUrl":"10.1016/j.actatropica.2026.107984","url":null,"abstract":"<div><div>For over 80 years, the genus <em>Coxiella</em> was considered monotypic, comprising only <em>Coxiella burnetii</em>, the aetiological agent of Q fever. Recent studies, however, have revealed several candidate species and genetic lineages associated with ticks, many of which act as endosymbionts that are essential for tick development. This association is particularly notable in the members of the <em>Rhipicephalus sanguineus</em> complex, where <em>Candidatus</em> Coxiella massiliensis (zoonotic) and <em>Candidatus</em> Coxiella mudrowiae (unknown pathogenicity) have been described. Given the close relationship between these ticks, domestic dogs, and humans, active surveillance for <em>Coxiella</em> species of medical and veterinary importance is crucial.</div><div>This study evaluated the presence and diversity of <em>Coxiella</em> species in 812 hard ticks: <em>Amblyomma mixtum</em> (<em>n</em> = 23), <em>Rhipicephalus linnaei</em> (<em>n</em> = 762), and <em>R. sanguineus</em> sensu stricto (<em>n</em> = 27) collected from December 2018 to November 2024 parasitizing dogs (<em>n</em> = 418), humans (<em>n</em> = 18), cattle (<em>n</em> = 4), and one cat across 17 states of Mexico.</div><div>A fragment (∼1500 base pair) of the <em>Coxiella</em> 16S ribosomal DNA (rDNA) gene was amplified, sequenced, and analysed phylogenetically. Additionally, published records of <em>Coxiella</em> endosymbionts associated with ticks parasitising dogs were compiled. Of 812 samples, 188 tested positive, revealing three <em>Coxiella</em> lineages closely related to known endosymbionts of <em>Rhipicephalus</em> and <em>Amblyomma</em> ticks. A review of 25 studies from across the globe identified four <em>Coxiella</em> taxa in 23 tick species from dogs across 19 countries. This is the first report of <em>Coxiella</em> lineages in dog-associated ticks in Mexico. Our findings expand the known diversity of the genus in the Neotropical region and underscore the need for further research to clarify their ecological roles and potential health implications.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107984"},"PeriodicalIF":2.5,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146002889","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 : 2026-01-17DOI: 10.1016/j.actatropica.2026.107986
Yani Zhang, Yuanfeng Wang, Tianmeng Song, Yichen Zhao, Zhenchao Zhang, Xiaowei Tian, Shuai Wang, Zhenke Yang, Xuefang Mei
Blastocystis hominis (B. hominis), one of the most common intestinal protozoa infecting humans worldwide, is associated with gastrointestinal disorders, yet it remains unclear whether it secretes virulence factors that interact with villin, a key cytoskeletal protein essential for brush border homeostasis and epithelial barrier function. In this study, we constructed a high-quality normalized full-length B. hominis cDNA library (capacity 5.2 × 10⁶ CFU; recombination rate 95.8%) and performed yeast two-hybrid screening using villin as bait. Thirty initial positive clones were obtained, and sequencing combined with BLAST identified 24 unique prey proteins. Among these, 11 were in-frame (ORF-true), 8 proteins were selected for pairwise verification, and 6 proteins were ultimately confirmed to specifically interact with villin, including pyridine nucleotide transhydrogenase (XP_014525634), an ATP/GTP-binding protein-like molecule (OAO14457), and four hypothetical proteins (XP_012896330, XP_012895057, XP_012893676, XP_012894607). GO and KEGG analyses performed on the 24 prey proteins indicated enrichment in cellular metabolic processes and membrane-associated pathways. These findings identify multiple B. hominis proteins capable of interacting with villin, provide new insights into parasite-induced epithelial damage, and offer potential biomarkers and candidate targets for drug and vaccine development against blastocystosis.
{"title":"Identification of villin-interacting virulence factors of Blastocystis hominis using yeast two-hybrid screening","authors":"Yani Zhang, Yuanfeng Wang, Tianmeng Song, Yichen Zhao, Zhenchao Zhang, Xiaowei Tian, Shuai Wang, Zhenke Yang, Xuefang Mei","doi":"10.1016/j.actatropica.2026.107986","DOIUrl":"10.1016/j.actatropica.2026.107986","url":null,"abstract":"<div><div><em>Blastocystis hominis</em> (<em>B. hominis</em>), one of the most common intestinal protozoa infecting humans worldwide, is associated with gastrointestinal disorders, yet it remains unclear whether it secretes virulence factors that interact with villin, a key cytoskeletal protein essential for brush border homeostasis and epithelial barrier function. In this study, we constructed a high-quality normalized full-length <em>B. hominis</em> cDNA library (capacity 5.2 × 10⁶ CFU; recombination rate 95.8%) and performed yeast two-hybrid screening using villin as bait. Thirty initial positive clones were obtained, and sequencing combined with BLAST identified 24 unique prey proteins. Among these, 11 were in-frame (ORF-true), 8 proteins were selected for pairwise verification, and 6 proteins were ultimately confirmed to specifically interact with villin, including pyridine nucleotide transhydrogenase (XP_014525634), an ATP/GTP-binding protein-like molecule (OAO14457), and four hypothetical proteins (XP_012896330, XP_012895057, XP_012893676, XP_012894607). GO and KEGG analyses performed on the 24 prey proteins indicated enrichment in cellular metabolic processes and membrane-associated pathways. These findings identify multiple <em>B. hominis</em> proteins capable of interacting with villin, provide new insights into parasite-induced epithelial damage, and offer potential biomarkers and candidate targets for drug and vaccine development against blastocystosis.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107986"},"PeriodicalIF":2.5,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146002827","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}
Timely serodiagnosis of Toxoplasma gondii is critical for HIV/AIDS patients, in whom latent infection can reactivate into life-threatening toxoplasmic encephalitis. This study aimed to evaluate the diagnostic performance of a novel recombinant T. gondii matrix antigen 1 (TgMAG1)-based indirect ELISA and a commercial latex agglutination test (LAT) for detecting anti-T. gondii IgG in HIV/AIDS patients, using the Sabin-Feldman dye test (DT) as the reference standard. A secondary objective was to determine the current prevalence of latent toxoplasmosis in this population in Thailand. We conducted a comparative serological evaluation using 348 residual clinical specimens collected from 2016 to 2019 from HIV/AIDS patients. All samples were tested using the in-house TgMAG1 ELISA, a commercial LAT, and the DT. The sensitivity, specificity, and agreement (kappa statistic) of each index test were calculated against the DT. The DT identified a T. gondii seroprevalence of 12.36% (43/348; 95% CI: 8.94–16.64). Compared to the DT, the TgMAG1-ELISA demonstrated a sensitivity of 72.09% and a specificity of 93.11%, with moderate agreement (κ = 0.598). The LAT showed a similar sensitivity of 69.76% but a higher specificity of 97.04%, achieving substantial agreement with the DT (κ = 0.696). In conclusion, both the TgMAG1-based ELISA and LAT demonstrated high specificity but moderate sensitivity compared to the reference standard. Consequently, while these assays are valuable screening tools in settings lacking the DT, their results require careful interpretation and potential confirmation in high-risk populations.
{"title":"Evaluation of recombinant Toxoplasma gondii matrix antigen MAG1 for toxoplasmosis screening in HIV/AIDS patients","authors":"Ruenruetai Udonsom , Charoonluk Jirapattharasate , Supaluk Popruk , Sumonmal Uttayamakul , Intira Tantawiwattananon , Manas Kotepui , Sukhontha Siri , Hirotake Mori , Yoshifumi Nishikawa , Aongart Mahittikorn","doi":"10.1016/j.actatropica.2026.107983","DOIUrl":"10.1016/j.actatropica.2026.107983","url":null,"abstract":"<div><div>Timely serodiagnosis of <em>Toxoplasma gondii</em> is critical for HIV/AIDS patients, in whom latent infection can reactivate into life-threatening toxoplasmic encephalitis. This study aimed to evaluate the diagnostic performance of a novel recombinant <em>T. gondii</em> matrix antigen 1 (TgMAG1)-based indirect ELISA and a commercial latex agglutination test (LAT) for detecting anti-<em>T. gondii</em> IgG in HIV/AIDS patients, using the Sabin-Feldman dye test (DT) as the reference standard. A secondary objective was to determine the current prevalence of latent toxoplasmosis in this population in Thailand. We conducted a comparative serological evaluation using 348 residual clinical specimens collected from 2016 to 2019 from HIV/AIDS patients. All samples were tested using the in-house TgMAG1 ELISA, a commercial LAT, and the DT. The sensitivity, specificity, and agreement (kappa statistic) of each index test were calculated against the DT. The DT identified a <em>T. gondii</em> seroprevalence of 12.36% (43/348; 95% CI: 8.94–16.64). Compared to the DT, the TgMAG1-ELISA demonstrated a sensitivity of 72.09% and a specificity of 93.11%, with moderate agreement (κ = 0.598). The LAT showed a similar sensitivity of 69.76% but a higher specificity of 97.04%, achieving substantial agreement with the DT (κ = 0.696). In conclusion, both the TgMAG1-based ELISA and LAT demonstrated high specificity but moderate sensitivity compared to the reference standard. Consequently, while these assays are valuable screening tools in settings lacking the DT, their results require careful interpretation and potential confirmation in high-risk populations.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107983"},"PeriodicalIF":2.5,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145994070","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 : 2026-01-13DOI: 10.1016/j.actatropica.2026.107981
Nandhini Vasu , Thangamathi Perumal , Vasthi Gnana Rani S , Suvaithenamudhan Suvaiyarasan , Kalaiselvi G , Prabu Kumar Seetharaman , Karthik Raja Ramalingam , Ananth Sivapunniyam
Mosquito-borne diseases, particularly dengue fever, pose a significant global health challenge, with Aedes aegypti serving as a primary vector. Conventional chemical insecticides have led to the emergence of resistance in mosquito populations, necessitating the development of sustainable and effective alternative control measures. In this study, biogenic zinc oxide (ZnO) – copper oxide (CuO) nanocomposite was synthesized using Aegle marmelos aqueous leaf extract (Am-NCs) and evaluated for its dual-action: larvicidal efficacy and resistance management potential against Ae. aegypti. The novelty of this research lies in the synergistic combination of ZnO and CuO nanoparticles, which exhibit enhanced toxicity through oxidative stress induction and enzymatic pathway interference. Characterization of the Am-NCs was carried out with advanced technical instrumentations, which confirmed the structural integrity, crystalline nature and nanoscale morphology of nanocomposites (NCs). The synthesized Am-NCs demonstrated significant larvicidal activity, achieving an LC₅₀ value of 5.429 µg/mL in IV-instar larvae and 5.695 µg/mL against pupae. The biochemical assays revealed substantial inhibition of key detoxification enzymes, including acetylcholinesterase (AChE), α-carboxylesterase, and β-carboxylesterase, exhibiting its potential for mitigating insecticide resistance. Histopathological analysis further confirmed severe neurotoxicity and midgut disruption in treated larvae, revealing the mode of action of Am-NCs. Additionally, Am-NCs exhibited effective antibacterial activity against Staphylococcus aureus and Escherichia coli, demonstrating their broad-spectrum efficacy. The present study showed inhibitory effects of Am-NCs on mosquito resistance-associated enzymes, offering a promising biopesticide alternative for integrated vector management strategies.
{"title":"Green synthesis of ZnOCuO nanocomposites for dengue vector control and antibacterial applications","authors":"Nandhini Vasu , Thangamathi Perumal , Vasthi Gnana Rani S , Suvaithenamudhan Suvaiyarasan , Kalaiselvi G , Prabu Kumar Seetharaman , Karthik Raja Ramalingam , Ananth Sivapunniyam","doi":"10.1016/j.actatropica.2026.107981","DOIUrl":"10.1016/j.actatropica.2026.107981","url":null,"abstract":"<div><div>Mosquito-borne diseases, particularly dengue fever, pose a significant global health challenge, with <em>Aedes aegypti</em> serving as a primary vector. Conventional chemical insecticides have led to the emergence of resistance in mosquito populations, necessitating the development of sustainable and effective alternative control measures. In this study, biogenic zinc oxide (ZnO) – copper oxide (CuO) nanocomposite was synthesized using <em>Aegle marmelos</em> aqueous leaf extract (Am-NCs) and evaluated for its dual-action: larvicidal efficacy and resistance management potential against <em>Ae. aegypti</em>. The novelty of this research lies in the synergistic combination of ZnO and CuO nanoparticles, which exhibit enhanced toxicity through oxidative stress induction and enzymatic pathway interference. Characterization of the Am-NCs was carried out with advanced technical instrumentations, which confirmed the structural integrity, crystalline nature and nanoscale morphology of nanocomposites (NCs). The synthesized Am-NCs demonstrated significant larvicidal activity, achieving an LC₅₀ value of 5.429 µg/mL in IV-instar larvae and 5.695 µg/mL against pupae. The biochemical assays revealed substantial inhibition of key detoxification enzymes, including acetylcholinesterase (AChE), α-carboxylesterase, and β-carboxylesterase, exhibiting its potential for mitigating insecticide resistance. Histopathological analysis further confirmed severe neurotoxicity and midgut disruption in treated larvae, revealing the mode of action of Am-NCs. Additionally, Am-NCs exhibited effective antibacterial activity against <em>Staphylococcus aureus</em> and <em>Escherichia coli</em>, demonstrating their broad-spectrum efficacy. The present study showed inhibitory effects of Am-NCs on mosquito resistance-associated enzymes, offering a promising biopesticide alternative for integrated vector management strategies.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107981"},"PeriodicalIF":2.5,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145987724","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 : 2026-01-13DOI: 10.1016/j.actatropica.2026.107980
Alessandro Falsini , Aurora Fiori , Emanuele Montomoli , Nataliia Muzyka , Denys Muzyka , Claudia Maria Trombetta
Influenza viruses infect a wide range of animal species and continue to pose a significant threat to global health. Influenza D virus (IDV), first identified in 2011, has emerged as a new pathogen with a broad host range and remains poorly understood. This seroepidemiological study aimed to investigate the circulation of IDVs in Ukraine by analysing serum samples from domestic, wild and pet animals collected between 2021 and 2024. All samples tested negative for influenza A viruses. The highest seroprevalence for the D/660 lineage was detected in horses (57%), followed by swine (10%), with sporadic positivity observed in wild and companion animals. Positivity for the D/OK lineage was lower across all species. Overall, these finding provide evidence of the circulation and predominance of the D/660 lineage as the major IDV circulating in Ukraine and underscore the importance of coordinated surveillance in livestock, wildlife, and at-risk human populations to fully evaluate the public health implications of this emerging pathogen.
{"title":"Circulation of influenza D virus in Ukraine: A multi-species serological study","authors":"Alessandro Falsini , Aurora Fiori , Emanuele Montomoli , Nataliia Muzyka , Denys Muzyka , Claudia Maria Trombetta","doi":"10.1016/j.actatropica.2026.107980","DOIUrl":"10.1016/j.actatropica.2026.107980","url":null,"abstract":"<div><div>Influenza viruses infect a wide range of animal species and continue to pose a significant threat to global health. Influenza D virus (IDV), first identified in 2011, has emerged as a new pathogen with a broad host range and remains poorly understood. This seroepidemiological study aimed to investigate the circulation of IDVs in Ukraine by analysing serum samples from domestic, wild and pet animals collected between 2021 and 2024. All samples tested negative for influenza A viruses. The highest seroprevalence for the D/660 lineage was detected in horses (57%), followed by swine (10%), with sporadic positivity observed in wild and companion animals. Positivity for the D/OK lineage was lower across all species. Overall, these finding provide evidence of the circulation and predominance of the D/660 lineage as the major IDV circulating in Ukraine and underscore the importance of coordinated surveillance in livestock, wildlife, and at-risk human populations to fully evaluate the public health implications of this emerging pathogen.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107980"},"PeriodicalIF":2.5,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974856","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 : 2026-01-12DOI: 10.1016/j.actatropica.2026.107978
Xiang Chen, Paula Moraga
Background:
Leptospirosis is a globally neglected zoonotic disease with heightened transmission in tropical regions. Brazil bears a disproportionate burden in Latin America, driven by socio-economic vulnerability, urban infrastructure deficiencies, occupational exposure, and hydrological factors such as rainfall and flooding. Despite its significance, spatio-temporal patterns of leptospirosis across Brazil’s diverse regions remain poorly understood. This study examines the spatial distribution, temporal dynamics, and gender-specific patterns of leptospirosis risk in Brazil from 2010 to 2023.
Methods:
We conducted a national-level retrospective analysis using confirmed leptospirosis cases and population data aggregated at the microregional level () from official surveillance systems. Descriptive statistics assessed overall trends. Spatio-temporal scan statistics with a discrete Poisson model identified high-risk clusters. Bayesian spatio-temporal models estimated annual relative risks (RRs) and 95% credible intervals for total, male, and female populations. An interactive dashboard was developed for dissemination.
Results:
A total of 48,190 cases were reported, with males accounting for 80.1%. Temporal variation was notable, with peaks in 2011 and 2018 and a sharp decline during the COVID-19 pandemic. Thirty significant clusters were identified, mainly in Acre and southern Brazil. RR estimates confirmed persistent endemicity in these regions, with some microregions exceeding . Gender-disaggregated analyses revealed divergent trends between males and females in several areas.
Conclusion:
This study highlights marked spatial heterogeneity and gender disparities in leptospirosis risk across Brazil. Persistent hotspots underscore the need for long-term, localized interventions. High-resolution spatio-temporal modeling and interactive tools can inform equitable, data-driven disease control strategies in endemic regions.
{"title":"Spatio-temporal dynamics of leptospirosis in Brazil between 2010 and 2023: Identifying high-risk regions and gender-specific patterns","authors":"Xiang Chen, Paula Moraga","doi":"10.1016/j.actatropica.2026.107978","DOIUrl":"10.1016/j.actatropica.2026.107978","url":null,"abstract":"<div><h3>Background:</h3><div>Leptospirosis is a globally neglected zoonotic disease with heightened transmission in tropical regions. Brazil bears a disproportionate burden in Latin America, driven by socio-economic vulnerability, urban infrastructure deficiencies, occupational exposure, and hydrological factors such as rainfall and flooding. Despite its significance, spatio-temporal patterns of leptospirosis across Brazil’s diverse regions remain poorly understood. This study examines the spatial distribution, temporal dynamics, and gender-specific patterns of leptospirosis risk in Brazil from 2010 to 2023.</div></div><div><h3>Methods:</h3><div>We conducted a national-level retrospective analysis using confirmed leptospirosis cases and population data aggregated at the microregional level (<span><math><mrow><mi>n</mi><mo>=</mo><mn>558</mn></mrow></math></span>) from official surveillance systems. Descriptive statistics assessed overall trends. Spatio-temporal scan statistics with a discrete Poisson model identified high-risk clusters. Bayesian spatio-temporal models estimated annual relative risks (RRs) and 95% credible intervals for total, male, and female populations. An interactive dashboard was developed for dissemination.</div></div><div><h3>Results:</h3><div>A total of 48,190 cases were reported, with males accounting for 80.1%. Temporal variation was notable, with peaks in 2011 and 2018 and a sharp decline during the COVID-19 pandemic. Thirty significant clusters were identified, mainly in Acre and southern Brazil. RR estimates confirmed persistent endemicity in these regions, with some microregions exceeding <span><math><mrow><mi>R</mi><mi>R</mi><mo>></mo><mn>20</mn></mrow></math></span>. Gender-disaggregated analyses revealed divergent trends between males and females in several areas.</div></div><div><h3>Conclusion:</h3><div>This study highlights marked spatial heterogeneity and gender disparities in leptospirosis risk across Brazil. Persistent hotspots underscore the need for long-term, localized interventions. High-resolution spatio-temporal modeling and interactive tools can inform equitable, data-driven disease control strategies in endemic regions.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107978"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974368","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 : 2026-01-12DOI: 10.1016/j.actatropica.2026.107979
Nargis Khan , Rani Faryal
Background
Ureteral stents are susceptible to colonization by Candida species, leading to stent-associated infections that are often difficult to treat. This study aimed to identify the Candida species colonizing ureteral stents and to assess the potential impact of their virulence factors on ureteral stent encrustation.
Material and methods
Candida species and Pseudomonas aeruginosa were isolated and identified from urine and ureteral stent samples. Phenotypic and genotypic detection of virulence factors and antifungal resistance was performed. In addition, the anticandidal activity of Pseudomonas species was evaluated.
Results
Among 25/95 patients, 32 Candida isolates were identified, of which 17 (53.1 %) were from ureteral stents and 15(46.8 %) were from urine samples. Candida albicans and non-albicans were significantly associated with stent colonization (p = 0.00001 and p = 0.000092). A significant association was observed between Candida-positive ureteral stents and concurrent urine culture positivity (p = 0.0153). P. aeruginosa was isolated in 29.5 % of patients, and all exhibited anticandidal activity. A significant inverse association (p < 0.05) was observed between the presence of P. aeruginosa and Candida colonization. Biofilm formation was detected in 51.8 % of stent-derived isolates. Urease activity was higher in ureteral stent isolates (94.1 %) (p = 0.04). Fluconazole and voriconazole resistance was 70 % and 53 % in ureteral stent isolates, and 47 % and 53 % in urine. The ALS1 and Hwp1 genes were detected in 78 % and 93 % of isolates, while the Erg11 gene was detected in 47 % isolates. C. albicans predominated in stent colonization, exhibiting enhanced virulence traits and antifungal resistance. These findings suggest that Candida species associated with ureteral stents contribute to encrustation, potentially complicating treatment and highlighting the need for targeted therapeutic strategies.
{"title":"Emerging role of Candida species virulence factors and antifungal resistance in ureteral stent colonization and encrustation","authors":"Nargis Khan , Rani Faryal","doi":"10.1016/j.actatropica.2026.107979","DOIUrl":"10.1016/j.actatropica.2026.107979","url":null,"abstract":"<div><h3>Background</h3><div>Ureteral stents are susceptible to colonization by <em>Candida</em> species, leading to stent-associated infections that are often difficult to treat. This study aimed to identify the <em>Candida</em> species colonizing ureteral stents and to assess the potential impact of their virulence factors on ureteral stent encrustation.</div></div><div><h3>Material and methods</h3><div><em>Candida</em> species and <em>Pseudomonas aeruginosa</em> were isolated and identified from urine and ureteral stent samples. Phenotypic and genotypic detection of virulence factors and antifungal resistance was performed. In addition, the anticandidal activity of <em>Pseudomonas</em> species was evaluated.</div></div><div><h3>Results</h3><div>Among 25/95 patients, 32 <em>Candida</em> isolates were identified, of which 17 (53.1 %) were from ureteral stents and 15(46.8 %) were from urine samples. <em>Candida albicans</em> and non-<em>albicans</em> were significantly associated with stent colonization (<em>p</em> = 0.00001 and <em>p</em> = 0.000092). A significant association was observed between <em>Candida</em>-positive ureteral stents and concurrent urine culture positivity (<em>p</em> = 0.0153). <em>P. aeruginosa</em> was isolated in 29.5 % of patients, and all exhibited anticandidal activity. A significant inverse association (<em>p</em> < 0.05) was observed between the presence of <em>P. aeruginosa</em> and <em>Candida</em> colonization. Biofilm formation was detected in 51.8 % of stent-derived isolates. Urease activity was higher in ureteral stent isolates (94.1 %) (<em>p</em> = 0.04). Fluconazole and voriconazole resistance was 70 % and 53 % in ureteral stent isolates, and 47 % and 53 % in urine. The <em>ALS1</em> and <em>Hwp1</em> genes were detected in 78 % and 93 % of isolates, while the <em>Erg11</em> gene was detected in 47 % isolates. <em>C. albicans</em> predominated in stent colonization, exhibiting enhanced virulence traits and antifungal resistance<em>.</em> These findings suggest that <em>Candida</em> species associated with ureteral stents contribute to encrustation, potentially complicating treatment and highlighting the need for targeted therapeutic strategies.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107979"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974857","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 : 2026-01-11DOI: 10.1016/j.actatropica.2026.107974
Babi Kyi Soe , Ana Huertas-Lopez , Hiroshi Sato , Poom Adisakwattana
Tick-borne zoonotic pathogens pose a growing threat across Southeast Asia, driven by high biodiversity, environmental change, and close human-animal contact. Yet, no systematic review has consolidated evidence on tick species and their host-pathogen associations across the region over the past decade. To address this gap, we conducted a systematic review and meta-analysis of studies published between 2015 and 2025 in accordance with PRISMA guidelines. Literature findings from PubMed and Web of Science retrieved 198 articles of which 122 articles were met with inclusion criteria. Included studies reported from nine countries with Thailand (37.7%) contributing the most, followed by Malaysia (36.1%). Research involvement of countries peaked in 2020 and 2025, with uneven geographic coverage. Universities were the leading contributors often through intra- and inter-regional collaborations. Samples were mainly derived from ectoparasites (50%), followed by animal blood (34.4%), and a combination of both sources (15.6%). Eight tick genera: 6 hard and 2 soft ticks were identified, with Rhipicephalus sanguineus being the most reported, underscoring its strong association with domestic hosts. Broader tick diversity was documented through sylvatic and environmental sampling. Of the 122 included studies, 57 studies detected tick-borne pathogens from 14 vertebrate animal hosts with notable detection of zoonotic involving the genera Anaplasma, Coxiella, and Borrelia. Dogs, cats, cattle, and rodents harbored the widest pathogen spectrum, with zoonotic significance. Meta analyses revealed a strong research bias toward domestic animals, with limited wildlife and transboundary settings occurred. Expanded cross-border collaborations and integrated One-Health approaches are needed to strengthen tick-borne pathogen detection and risk assessment.
在生物多样性高、环境变化和人与动物密切接触的推动下，蜱传人畜共患病原体在东南亚构成越来越大的威胁。然而，在过去十年中，没有系统的综述对该地区蜱虫物种及其宿主-病原体关联的证据进行了整合。为了解决这一差距，我们根据PRISMA指南对2015年至2025年间发表的研究进行了系统回顾和荟萃分析。从PubMed和Web of Science检索文献198篇，其中122篇符合纳入标准。纳入的研究报告来自9个国家，其中泰国（37.7%）贡献最多，其次是马来西亚（36.1%）。各国参与的研究在2020年和2025年达到顶峰，地理覆盖不均衡。大学往往通过区域内和区域间合作成为主要贡献者。样本主要来自体外寄生虫（50%），其次是动物血液（34.4%），两种来源的混合（15.6%）。共鉴定出8个蜱属：6个硬蜱属和2个软蜱属，其中报道最多的是血头蜱属，表明其与国内宿主的联系较强。通过森林和环境取样记录了更广泛的蜱虫多样性。在纳入的122项研究中，57项研究从14种脊椎动物宿主中检测到蜱传病原体，其中显著检测到人畜共患病，涉及无形体属、克希氏体属和伯氏体属。狗、猫、牛和啮齿动物携带最广泛的病原体谱，具有人畜共患的意义。Meta分析显示，研究偏向于家畜，野生动物和跨界环境有限。需要扩大跨境合作和综合的“一个健康”方法，以加强蜱传病原体的检测和风险评估。
{"title":"Ticks and tick-borne pathogens with zoonotic importance in animals in Southeast Asia: A decade of evidence from systematic review and meta-analysis","authors":"Babi Kyi Soe , Ana Huertas-Lopez , Hiroshi Sato , Poom Adisakwattana","doi":"10.1016/j.actatropica.2026.107974","DOIUrl":"10.1016/j.actatropica.2026.107974","url":null,"abstract":"<div><div>Tick-borne zoonotic pathogens pose a growing threat across Southeast Asia, driven by high biodiversity, environmental change, and close human-animal contact. Yet, no systematic review has consolidated evidence on tick species and their host-pathogen associations across the region over the past decade. To address this gap, we conducted a systematic review and meta-analysis of studies published between 2015 and 2025 in accordance with PRISMA guidelines. Literature findings from PubMed and Web of Science retrieved 198 articles of which 122 articles were met with inclusion criteria. Included studies reported from nine countries with Thailand (37.7%) contributing the most, followed by Malaysia (36.1%). Research involvement of countries peaked in 2020 and 2025, with uneven geographic coverage. Universities were the leading contributors often through intra- and inter-regional collaborations. Samples were mainly derived from ectoparasites (50%), followed by animal blood (34.4%), and a combination of both sources (15.6%). Eight tick genera: 6 hard and 2 soft ticks were identified, with <em>Rhipicephalus sanguineus</em> being the most reported, underscoring its strong association with domestic hosts. Broader tick diversity was documented through sylvatic and environmental sampling. Of the 122 included studies, 57 studies detected tick-borne pathogens from 14 vertebrate animal hosts with notable detection of zoonotic involving the genera <em>Anaplasma, Coxiella</em>, and <em>Borrelia</em>. Dogs, cats, cattle, and rodents harbored the widest pathogen spectrum, with zoonotic significance. Meta analyses revealed a strong research bias toward domestic animals, with limited wildlife and transboundary settings occurred. Expanded cross-border collaborations and integrated One-Health approaches are needed to strengthen tick-borne pathogen detection and risk assessment.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107974"},"PeriodicalIF":2.5,"publicationDate":"2026-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145964916","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 : 2026-01-10DOI: 10.1016/j.actatropica.2026.107977
Juan José Bustillos Herrera , Jonathan Patricio Mora Montalvo , Paúl Andrés Quinatoa Tutillo , Fátima Anabel Padilla Narváez , Diego Omar Morales Viteri
Dengue virus (DENV) remains a significant public health concern in Ecuador, with Aedes aegypti as the primary vector. In recent years, the detection of Aedes albopictus has raised concerns about potential changes in vector dynamics. This study reports entomo-virological surveillance conducted in Santo Domingo de los Tsáchilas, Ecuador, from June 2023 to September 2024. Mosquito specimens were collected using aspirators and CDC light traps, while immature stages were manually sampled from artificial breeding sites. Morphological identification was performed using pictorial keys, and molecular detection for arboviruses was carried out with the STANDARD M10 module. A total of 3918 mosquito specimens were identified and analyzed using molecular tools, with Ae. aegypti accounting for 90.04 % of the samples. Molecular screening detected Dengue Virus 1 (DENV-1) and Dengue Virus 2 (DENV-2) serotypes exclusively in Aedes aegypti pools, with a positivity rate of 33.69 %. No Dengue Virus 3 (DENV-3), Dengue Virus 4 (DENV-4) serotypes, Zika, chikungunya, yellow fever, or West Nile virus were detected. Spatial and entomological risk analyses identified high-risk localities, particularly in urban parishes such as Río Verde and Santo Domingo, where both serotypes were co-circulating. Aedes albopictus was present in the study area but tested negative for all screened arboviruses. These findings highlight the persistent epidemiological importance of Aedes aegypti and the need for continued surveillance in areas where Aedes albopictus has recently established.
{"title":"Entomological surveillance in active dengue transmission areas of Santo Domingo de los Tsáchilas - Ecuador: Epidemiological importance of Aedes aegypti and the recent establishment of Aedes albopictus","authors":"Juan José Bustillos Herrera , Jonathan Patricio Mora Montalvo , Paúl Andrés Quinatoa Tutillo , Fátima Anabel Padilla Narváez , Diego Omar Morales Viteri","doi":"10.1016/j.actatropica.2026.107977","DOIUrl":"10.1016/j.actatropica.2026.107977","url":null,"abstract":"<div><div>Dengue virus (DENV) remains a significant public health concern in Ecuador, with <em>Aedes aegypti</em> as the primary vector. In recent years, the detection of <em>Aedes albopictus</em> has raised concerns about potential changes in vector dynamics. This study reports entomo-virological surveillance conducted in Santo Domingo de los Tsáchilas, Ecuador, from June 2023 to September 2024. Mosquito specimens were collected using aspirators and CDC light traps, while immature stages were manually sampled from artificial breeding sites. Morphological identification was performed using pictorial keys, and molecular detection for arboviruses was carried out with the STANDARD M10 module. A total of 3918 mosquito specimens were identified and analyzed using molecular tools, with <em>Ae. aegypti</em> accounting for 90.04 % of the samples. Molecular screening detected Dengue Virus 1 (DENV-1) and Dengue Virus 2 (DENV-2) serotypes exclusively in <em>Aedes aegypti</em> pools, with a positivity rate of 33.69 %. No Dengue Virus 3 (DENV-3), Dengue Virus 4 (DENV-4) serotypes, Zika, chikungunya, yellow fever, or West Nile virus were detected. Spatial and entomological risk analyses identified high-risk localities, particularly in urban parishes such as Río Verde and Santo Domingo, where both serotypes were co-circulating. <em>Aedes albopictus</em> was present in the study area but tested negative for all screened arboviruses. These findings highlight the persistent epidemiological importance of <em>Aedes aegypti</em> and the need for continued surveillance in areas where <em>Aedes albopictus</em> has recently established.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":"274 ","pages":"Article 107977"},"PeriodicalIF":2.5,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145958420","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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