Memorias do Instituto Oswaldo Cruz最新文献

{"title":"Beyond Leishmania: hidden trypanosomatid diversity reveals complex parasite-sand fly networks in southeastern Brazil.","authors":"Ana Paula Isnard, Amanda Caroline Corrêa Madureira, Gustavo Mayr de Lima Carvalho, Mariana Lourenço Freire, Daniel Moreira de Avelar, Lileia Gonçalves Diotaiuti, José Dilermando Andrade Filho, Felipe Dutra-Rêgo","doi":"10.1590/0074-02760250260","DOIUrl":"10.1590/0074-02760250260","url":null,"abstract":"<p><strong>Background: </strong>Sand flies (Diptera: Psychodidae) are well-known vectors of Leishmania, yet their associations with other trypanosomatids remain poorly understood. Expanding knowledge on these interactions is essential to elucidate the ecological diversity of parasites circulating in natural and periurban environments.</p><p><strong>Objective: </strong>To characterise sand fly species composition and assess the diversity of trypanosomatids naturally infecting sand flies in the Serra do Cipó district, Minas Gerais, Brazil.</p><p><strong>Methods: </strong>Sand flies were collected between 2023 and 2025 in the Mata da Tapera and nine surrounding peridomestic sites using Centre for Disease Control light trap (CDC-LT) and a Shannon trap. Females were examined by midgut dissection and screened individually for trypanosomatids using nested polymerase chain reaction (PCR) targeting the 18S rRNA V7-V8 region, followed by sequencing and phylogenetic analyses.</p><p><strong>Findings: </strong>A total of 1,460 sand flies representing 21 species were collected, with Pintomyia pessoai (35.5%) being the most abundant. No flagellates were observed in 105 dissected females. Molecular screening of 730 females revealed 12 positives (overall positivity = 1.6%), including Leishmania infantum in Pi. pessoai, Pi. christenseni, and Pa. barretoi; L. braziliensis in Pi. monticola; and non-Leishmania taxa such as Herpetomonas samuelpessoai, Novymonas esmeraldas, a representative of Strigomonadinae, Trypanosoma sp. (Anura clade), and a lineage related to Sergeia.</p><p><strong>Main conclusion: </strong>These findings confirm the circulation of Leishmania in Serra do Cipó while revealing hidden trypanosomatid diversity spanning at least five genera. The results suggest that sand flies may act as ecological \"hubs\", transiently interacting with multiple parasite lineages beyond the classical Leishmania cycle, highlighting the need to broaden the ecological perspective in sand fly-parasite studies.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"121 ","pages":"e250260"},"PeriodicalIF":2.5,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13143167/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147839963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aedes aegypti salivary gland extract enhances Zika virus replication through immune modulation.","authors":"Gabriel Hilario, Gilson Pires Dorneles, Deise Nascimento de Freitas, Onilda Santos da Silva, Josiane Somariva Prophiro, Tiago Fazolo, Rafael Rahal Guaragna Machado, Cristina Bonorino, Danielle Bruna Leal Oliveira, Simone Gonçalves da Fonseca, Pedro Roosevelt Torres Romão, Luiz Carlos Rodrigues","doi":"10.1590/0074-02760250272","DOIUrl":"10.1590/0074-02760250272","url":null,"abstract":"<p><strong>Background: </strong>Mosquito saliva contains bioactive molecules that modulate host immunity and may influence arboviral infection. The contribution of Aedes aegypti salivary gland extract (SGE) to viral replication and immune regulation during Zika virus (ZIKV) infection remains poorly understood.</p><p><strong>Objectives: </strong>To investigate the immunomodulatory effects of Ae. aegypti SGE during ZIKV infection.</p><p><strong>Methods: </strong>Peripheral blood mononuclear cells (PBMCs) and murine antigen-presenting cell lines were exposed to ZIKV with or without SGE. Viral replication was measured by quantitative polymerase chain reaction (qPCR), cell death and immune subsets by flow cytometry, oxidative stress markers by biochemical assays, and cytokine production by enzyme-linked immunosorbent assay (ELISA).</p><p><strong>Findings: </strong>SGE enhanced ZIKV replication, particularly in PBMCs, with increased RNA copies (median Δ = +1,779), reduced late apoptosis of CD4⁺ T cells (p = 0.0055), dendritic cell death (p < 0.01), and impaired T-cell proliferation. SGE attenuated ZIKV-induced oxidative damage by restoring glutathione levels, reducing lipid and protein oxidation (p < 0.001), and increasing nitric oxide (NO) production. Cytokine profiling revealed suppression of interferon-y (IFN-γ) (p < 0.001) and induction of interleukin-4 (IL-4) (p < 0.0001), indicating a Th2-skewed response. Murine cell lines confirmed SGE-driven cytokine modulation.</p><p><strong>Main conclusions: </strong>Ae. aegypti SGE alters host immune homeostasis, favouring ZIKV infection by weakening antiviral defences and redirecting immune and redox pathways, thereby facilitating viral expansion.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"121 ","pages":"e250272"},"PeriodicalIF":2.5,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13143171/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147839960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A non-destructive image-based approach to quantify blood meal size in Lutzomyia longipalpis (Diptera: Psychodidae).","authors":"Lidiane Medeiros da Costa, Maurício Roberto Viana Sant'Anna, Laura Aquino Generoso, Geisler Peixoto da Cruz, Grasielle Caldas D'Ávila Pessoa, Ricardo Nascimento Araujo, Nelder de Figueiredo Gontijo, Marcos Horacio Pereira","doi":"10.1590/0074-02760250158","DOIUrl":"10.1590/0074-02760250158","url":null,"abstract":"<p><strong>Background: </strong>Phlebotomine sand flies are hematophagous vectors of major human pathogens, including Leishmania spp., with blood ingestion essential for reproduction and vector competence. Accurate quantification of blood meal volume is crucial for understanding physiological processes and transmission dynamics.</p><p><strong>Objectives: </strong>Here, we introduce a novel, non-destructive image-based method to estimate blood intake in Lutzomyia longipalpis, the principal vector of Leishmania infantum in the Americas.</p><p><strong>Methods: </strong>High-resolution images of unfed and blood-fed females were analysed using Fiji ImageJ (open-source software) when several morphometric parameters were measured and validated against biochemical haemoglobin (Hb) quantification.</p><p><strong>Findings: </strong>Blood-fed females exhibited a 56.6% increase in abdominal width and a shift toward a rounded body shape, which was strongly correlated with a visible transilluminated abdominal area (R² = 0.92). Some parameters, such as mean grey value and abdominal length, showed a low to moderate correlation with Hb content (R < 0.60). However, the correlation with abdominal area and width was R ≈ 0.90, indicating those are reliable parameters that can be used to estimate blood intake by Lu. longipalpis females.</p><p><strong>Main conclusions: </strong>Unlike spectrophotometric methods, this approach preserves specimen integrity, which, in theory, enables longitudinal studies on physiology and host-parasite interactions. This methodology offers a reliable, scalable, and cost-effective alternative for estimating blood meal.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"121 ","pages":"e250158"},"PeriodicalIF":2.5,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13143169/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147839986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mitochondrial genome refinement and comparative phylogenetics of Parastrongyloides trichosuri (KNP strain; Nematoda: Strongyloididae) from South Africa.","authors":"Kwangjae Cho, Minkyung Kim, Jun Won Park, Yang-Kyu Choi, Won Gi Yoo","doi":"10.1590/0074-02760250294","DOIUrl":"10.1590/0074-02760250294","url":null,"abstract":"<p><strong>Background: </strong>Parastrongyloides trichosuri Mackerras, 1959 (Nematoda: Strongyloididae) is a facultatively parasitic nematode infecting the common brushtail possum. A previously reported mitochondrial genome (mitogenome) from a Kruger National Park (KNP) isolate (GenBank: NC_028620) is incomplete, lacking the nad3 gene and the noncoding region (NCR), limiting its utility for comparative and phylogenetic studies.</p><p><strong>Objectives: </strong>This study aimed to reconstruct, annotate, and validate a complete mitogenome of P. trichosuri (KNP strain) to enhance genomic accuracy and phylogenetic resolution within Strongyloididae.</p><p><strong>Methods: </strong>Whole-genome sequencing data (SRA: ERS056619) were reanalysed. Missing genes, including tRNA-Glu and atp6, were manually curated using BLASTn searches against Rfam v15, while cox3 and nad3 were confirmed through transmembrane topology analysis.</p><p><strong>Findings: </strong>The reconstructed mitogenome was 13,809 bp long, comprising 12 protein-coding genes, 22 tRNAs, 2 rRNAs, and a 539-bp tandem-repeat NCR. Gene order and structure were consistent with other Strongyloididae mitogenomes. Phylogenetic analysis supported P. trichosuri as a distinct lineage within the family. The annotated sequence has been deposited in the Third Party Annotation database in GenBank (accession No. BK075097).</p><p><strong>Main conclusions: </strong>This improved mitogenome fills an existing genomic gaps and provides a reliable reference for future comparative, phylogenetic, and evolutionary studies of Strongyloididae.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"121 ","pages":"e250294"},"PeriodicalIF":2.5,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13123268/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147775682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coxiella burnetii in free-living feral pigs (Sus scrofa) in Brazil.","authors":"Jorlan Fernandes, Wania Guimarães Dos Santos, Matheus Ribeiro da Silva Assis, Martha Lima Brandão, Marcione Brito de Oliveira, Jairo Dias Barreira, Dominique Elvira Souza Freitas, José Luís Passos Cordeiro, Luiz Flamarion Barbosa de Oliveira, Elba Regina Sampaio de Lemos","doi":"10.1590/0074-02760250284","DOIUrl":"https://doi.org/10.1590/0074-02760250284","url":null,"abstract":"<p><strong>Background: </strong>Coxiella burnetii, the etiological agent of coxiellosis in animals and Q fever in humans, is a zoonotic pathogen of global relevance that can infect a wide range of species. Although several domestic and wild animals are involved in the natural cycle, the role of wildlife hosts remains poorly understood.</p><p><strong>Objectives: </strong>Our study aimed to investigate the presence of C. burnetii in feral pigs hunted in Brazilian Pantanal wetland.</p><p><strong>Methods: </strong>In this study, 36 free-living feral pigs legally hunted in Mato Grosso State, Brazil, were sampled. Sera were tested by enzyme-linked immunosorbent assay (ELISA), and spleen, liver, sera and tick samples were analysed by polymerase chain reaction (PCR).</p><p><strong>Findings: </strong>Serological evidence of exposure was detected in 22.2% [8/36; 95% confidence interval (CI): 11.7% - 38.1%], while C. burnetii DNA was found in one spleen sample (1/36 - 2.8%; 95% CI: 0.1% - 14.5%). Only Coxiella-like endosymbiont was detected in Amblyomma sculptum ticks (9/23 - 39.13%; 95% CI: 22.2% - 59.2%).</p><p><strong>Main conclusions: </strong>These results represent the first detection of C. burnetii in free-living feral pigs in Brazil and suggest potential exposure of this invasive mammal species to the pathogen. The findings underscore the need for broader surveillance of C. burnetii at the wildlife-livestock-human interface in Brazil.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"121 ","pages":"e250284"},"PeriodicalIF":2.5,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13102456/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147775695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immunoinformatic analysis for identifying immunogenic antigens from the complete proteome of Giardia lamblia.","authors":"David Ortega-Tirado, Carlos A Velazquez-Valdez, Thania Garzon, Leslie Bracamontes-Picos, Gloria Lopez-Romero, Carlos Velazquez","doi":"10.1590/0074-02760250216","DOIUrl":"https://doi.org/10.1590/0074-02760250216","url":null,"abstract":"<p><strong>Background: </strong>Giardia lamblia is a parasite that infects humans. To date, there is no vaccine available for human giardiasis. Thus, discovering new immunogenic antigens is crucial for the rational design of a vaccine.</p><p><strong>Objectives: </strong>This study aimed to identify the main immunogenic antigens of G. lamblia from its entire proteome using immunoinformatic and data science techniques. To our knowledge, this is the first study to systematically identify immunogenic antigens of G. lamblia across its complete proteome, providing a comprehensive map of potential immunogenic antigens.</p><p><strong>Methods: </strong>Briefly, FASTA sequences of G. lamblia isolates WB and GS were submitted to the NetMHCII 2.3 predictor. The analysis was conducted for five murine major histocompatibility complex (MHC)-II molecules: I-Ab, I-Ad, I-Ed, I-Ak, and I-Ek. Python 3.9 was used to develop custom code for data processing and analysis.</p><p><strong>Findings: </strong>We identified 414 potential immunogenic polypeptides for isolate WB and 350 for isolate GS. For both isolates, most polypeptides contained peptides with high affinity for I-Ab and I-Ek. Notably, no polypeptides with high affinity for I-Ak were detected. Homologous potential immunogenic antigens (129 polypeptides) were identified in both isolates. The analysis revealed that 12 potential immunogenic polypeptides from isolate WB and 10 from isolate GS are part of the Giardia secretome. Additionally, promiscuous polypeptides that bind to at least two different MHC-II molecules were found in both isolates.</p><p><strong>Main conclusions: </strong>These findings lay a valuable foundation for the rational development of a vaccine against human giardiasis and show a computational strategy that can be applied to the study of other pathogens.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"121 ","pages":"e250216"},"PeriodicalIF":2.5,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13090037/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147775751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immune dysregulation, apoptosis impairment, and enhanced seroreactivity to Anisakis simplex in Crohn's disease: interplay of IL-7/IL-7R signalling and CD132 deficiency","authors":"Carmen Cuéllar, Carolina Hurtado-Marcos, Elizabeth Valdivieso, Lucianna Vaccaro, Juan González-Fernández, Ana Isabel Jiménez, Jaume Pérez-Griera, Salvador Benlloch, Cirilo Amorós, Rafael Gil-Borrás, Rosa Sorando-Serra, María José Cano-Cano, Juan Carlos Andreu-Ballester","doi":"10.1590/0074-02760250129","DOIUrl":"10.1590/0074-02760250129","url":null,"abstract":"<p><strong>Background: </strong>In previous studies, we identified a deficiency of γδ T cells and an increased prevalence of anti-Anisakis simplex antibodies in patients with Crohn's disease (CD). Additionally, decreased gene expression of the interleukin 2 (IL-2) receptor γ subunit (CD132) was observed in tissues from CD patients.</p><p><strong>Objective: </strong>To analyse the gene expression of IL-7 and its receptors in tissues from CD patients and to explore its relationship with anti-A. simplex antibodies.</p><p><strong>Methods: </strong>52 patients diagnosed with CD were compared with a control group of 52 healthy individuals. Peripheral blood samples were analysed to assess levels of anti-A. simplex antibodies and IL-7. In addition, intestinal tissue samples from 20 subjects in each group were examined to evaluate IL-7 gene expression, IL-7 protein levels, the IL-2 receptor γ subunit (CD132), the IL-7 receptor α subunit (CD127), and caspase-3 expression.</p><p><strong>Findings: </strong>Anti-A. simplex antibody levels were elevated in patients with CD. Caspase-3 expression was significantly reduced in the tissues of CD patients with anti-A. simplex IgA, and this reduction extended to IgG and IgE in healthy individuals. A negative correlation was observed between caspase-3 levels and serum anti-A. simplex IgA, as well as IL-7 levels in the tissues of CD patients. In healthy subjects, tissue IL-7 levels were lower in those positive for anti-A. simplex IgA, while serum IL-7 levels were higher in individuals positive for anti-A. simplex IgG.</p><p><strong>Main conclusions: </strong>This study revealed the interplay between IL-7 signalling, γδ T cell deficiency, and immune responses to A. simplex in CD. Our findings underscored a cause-effect relationship between CD132 deficiency, γδ T cell depletion, and defective mucosal immunity, which may drive both CD inflammation and susceptibility to parasitic infections like A. simplex.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"121 ","pages":"e250129"},"PeriodicalIF":2.5,"publicationDate":"2026-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147690721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Retinal pigment epithelium drives macrophage migration during Toxoplasma gondii infection in vitro","authors":"Alex Martins Nasaré, Roberto Carlos Tedesco, Paula Andrea Faria Waziry, Lorena de Paula Pantaleon, Esther Lopes Ricci, Luís Antônio Baffile Leoni, André Rinaldi Fukushima, Andres Jimenez Galisteo Junior","doi":"10.1590/0074-02760250141","DOIUrl":"10.1590/0074-02760250141","url":null,"abstract":"<p><strong>Background: </strong>Ocular toxoplasmosis is a leading cause of infectious posterior uveitis worldwide. The retinal pigment epithelium (RPE), a key barrier and immunomodulatory layer in the eye, is directly targeted by Toxoplasma gondii during infection. However, its role in orchestrating the local immune response remains unclear.</p><p><strong>Objectives: </strong>To investigate whether RPE cells actively drive macrophage migration during T. gondii infection in vitro, and to identify associated cytokine profiles.</p><p><strong>Methods: </strong>Adult retinal pigment epithelial cells (ARPE)-19 and primary RPE cells were exposed to tachyzoites, soluble antigens or conditioned supernatants. Macrophage migration was assessed using Transwell® and under-agar assays. Cytokines were quantified by cytometric bead array.</p><p><strong>Findings: </strong>Both ARPE-19 and primary RPE exhibited chemotaxis toward parasite antigens (0.12 - 0.5 μg), and enhanced interleukin-6 (IL-6), IL-10 and tumor necrosis factor-α (TNF-α) secretion. Co-culture with RAW 264.7 macrophages further amplified cytokine production. Primary RPE from infected animals occluded 90% of Transwell® pores within 24h. IL-6 and IL-10 levels strongly correlated with migratory activity (r = 0.82 and 0.77, respectively).</p><p><strong>Main conclusions: </strong>RPE cells are not passive targets but active participants in the ocular immune response to T. gondii. By secreting IL-6 and IL-10, they establish a chemotactic environment that recruits macrophages. These insights identify the RPE-cytokine-macrophage axis as a potential therapeutic target in ocular toxoplasmosis.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"121 ","pages":"e250141"},"PeriodicalIF":2.5,"publicationDate":"2026-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13078792/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147690673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The complexity of the population dynamics of Triatoma brasiliensis in rural north-east Brazil indicated by genetic characterisation.","authors":"Luiz Osvaldo Rodrigues Silva, Carlota Josefovicz Belisário, Flávio Campos Ferreira, Jorg Heukelbach, Liléia Diotaiuti, Claudia Mendonça Bezerra","doi":"10.1590/0074-02760250076","DOIUrl":"10.1590/0074-02760250076","url":null,"abstract":"<p><strong>Background: </strong>Triatoma brasiliensis, the primary Chagas disease (CD) vector in the north-east of Brazil, poses a significant challenge for control due to its adaptability and ability to colonise anthropic environments. The limited number of previous studies on the population dynamics of T. brasiliensis hinders the development of effective control strategies.</p><p><strong>Objectives: </strong>This study characterises the genetic variability of T. brasiliensis populations in Jaguaruana using microsatellite markers, in order to understand the population processes of triatomine infestation and reinfestation.</p><p><strong>Methods: </strong>We analysed the genetic structure of 229 T. brasiliensis specimens collected in the municipality of Jaguaruana in the north-east Brazilian State of Ceará using microsatellite markers.</p><p><strong>Findings: </strong>Hardy-Weinberg disequilibrium prevailed, with substantial genetic variability (67.2%) among individuals and inbreeding, but genetic differentiation lacked correlation with geographical distance (Mantel's test).</p><p><strong>Main conclusions: </strong>The complex population dynamics in Jaguaruana revealed diverse sources of anthropogenic colonisation, impacting regional control. This study underscores the necessity of comprehending intricate infestation processes for planning effective vector surveillance and control strategies.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"121 ","pages":"e250076"},"PeriodicalIF":2.5,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13035281/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147593165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sustained Oropouche virus transmission in Rio de Janeiro's Atlantic Forest: genomic evidence over a two-year period.","authors":"Ighor Arantes, Fernanda de Bruycker-Nogueira, Carla de Oliveira, Patrícia Carvalho Sequeira, Otília Lupi, Michele Borges, Carolina Lopes Melo, Michelle Brendolin, Antonio Braga, Luciane de Souza Velasque, Andréa Cony Cavalcanti, Adriana Cardoso Camargo, Fábio Burack da Costa, Cristiane Gomes de Castro Moreira, Vanessa Zaquieu Dias, Thiago de Jesus Sousa, Felipe Donateli Gatti, Gabriela Colombo de Mendonça, Joana Zorzal Nodari, Rodrigo Ribeiro-Rodrigues, Edson Delatorre, Guilherme Calvet, Felipe Gomes Naveca, Patricia Brasil, Ana Maria Bispo de Filippis, Gonzalo Bello","doi":"10.1590/0074-02760250181","DOIUrl":"10.1590/0074-02760250181","url":null,"abstract":"<p><strong>Background: </strong>Oropouche virus (OROV), an arbovirus endemic to the Amazon region, has recently expanded into non-endemic areas including Rio de Janeiro State, Brazil.</p><p><strong>Objective: </strong>To characterise the spatio-temporal dynamics and ecological factors associated with OROV transmission in Rio de Janeiro during 2024-2025.</p><p><strong>Methods: </strong>We analysed OROV case-associated ecological factors and performed a phylodynamic analysis on 40 viral genomes, comprising 35 new and five published sequences, sampled from 15 municipalities across the state during 2024-2025.</p><p><strong>Findings: </strong>OROV cases showed significant positive correlations with forest area (r = 0.50, p < 0.0001), banana harvest area (r = 0.39, p < 0.01), and cassava harvest area (r = 0.29, p < 0.05); but these factors were autocorrelated, suggesting a confounded relationship. We identified two OROV sub-clades circulating in the Rio de Janeiro State. The OROVRJ/ES sub-clade was likely introduced into the Southern Fluminense region around January 2024, spread primarily by short (> 2 km, 50% of events) and mid-distance movements (2-9 km; 30%) with a mean dispersal rate of 0.3 km/day, and seed outbreaks in Metropolitan and Northwest Fluminense regions in 2025. The OROVES-I clade was likely introduced into Central Fluminense and Coastal Lowlands regions, later spreading to the Northern Fluminense region.</p><p><strong>Main conclusions: </strong>Following its introduction in early 2024, OROV persisted in Rio de Janeiro State by spreading through short-distance movements among municipalities with high forest cover and agricultural areas. The sustained multi-year OROV transmission in the Atlantic Forest biome highlights the potential for establishment of endemic cycles beyond the Amazon region and the need for enhanced surveillance in extra-Amazonian areas, where OROV will evolve in a different ecosystem.</p>","PeriodicalId":18469,"journal":{"name":"Memorias do Instituto Oswaldo Cruz","volume":"121 ","pages":"e250181"},"PeriodicalIF":2.5,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13035214/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147593190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}