Pathogens最新文献

{"title":"Unusual Localization of Presumptive <i>Sarcina ventriculi</i> in the Terminal Ileum: A Case Report.","authors":"Dua Abuquteish, Daifallah AlNawawi, Reza Khorvash, Osama M Abu Ata, Nidal Almasri","doi":"10.3390/pathogens14090931","DOIUrl":"10.3390/pathogens14090931","url":null,"abstract":"<p><strong>Background: </strong><i>Sarcina ventriculi</i> is a bacterium predominantly reported in the stomach and associated with emphysematous gastritis, delayed gastric emptying, gastroparesis, or gastric outlet obstruction. Its prevalence is increasing among patients with a history of organ transplants, immunosuppression, and graft-versus-host disease (GVHD). This bacterium can be detected on histology with characteristic tetrad packet morphology; however, confirmation requires PCR and molecular studies. The role of <i>Sarcina ventriculi</i> in human diseases is not fully understood and has unclear clinical significance. While certain studies point to a possible pathogenic role, others regard its detection as incidental with no clear clinical consequence.</p><p><strong>Case presentation: </strong>Herein, we report a case of a 39-year-old male patient with primary refractory cHL, stage IVb, who underwent an autologous bone marrow transplant (BMT) and an allogeneic stem cell infusion. His post-transplant course was complicated by chronic kidney disease (CKD), malnutrition, depression, myopathy, skin, and colon GVHD. He eventually developed sepsis, was admitted to the ICU and developed multiorgan failure and passed away. The patient developed diarrhea, and the gastrointestinal specialist was consulted and revealed ulcerated ileitis and colitis. Biopsies were taken to evaluate for CMV infection and GVHD. The terminal ileum biopsy mainly revealed ulceration with granulation tissue formation and abundant microorganisms arranged in distinctive tetrads, characteristic of <i>Sarcina ventriculi</i>. The colonic biopsies were consistent with GVHD grade II.</p><p><strong>Conclusions: </strong>The significance of Sarcina microorganisms and their mechanisms of injury remain poorly understood. The identification of <i>Sarcina ventriculi</i> in the terminal ileum, which is an unusual and previously unreported finding, adds a new perspective to our understanding of its pathogenic potential and anatomical distribution. While the patient's clinical decline was influenced by multiple factors, including GVHD, recurrent sepsis, and multiorgan failure, the role of <i>Sarcina ventriculi</i> as a potential exacerbating factor remains unclear.</p>","PeriodicalId":19758,"journal":{"name":"Pathogens","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12472762/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145177370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ecological Perspectives on Leishmaniasis Parasitism Patterns: Evidence of Possible Alternative Vectors for <i>Leishmania</i> (<i>Leishmania</i>) <i>infantum</i> (syn. <i>L. chagasi</i>) and <i>Leishmania</i> (<i>Viannia</i>) <i>braziliensis</i> in Piauí, Brazil.","authors":"Raimundo Leoberto Torres de Sousa, Thais Araujo-Pereira, Silvia Alcântara Vasconcelos, Simone Mousinho Freire, Oriana Bezerra Lima, Jacenir Reis Dos Santos-Mallet, Mauricío Luiz Vilela, Victor Manoel de Sousa Vasconcelos, Etielle Barroso de Andrade, Régis Gomes, Clarissa Teixeira, Bruno Moreira Carvalho, Daniela Pita-Pereira, Constança Britto","doi":"10.3390/pathogens14090930","DOIUrl":"10.3390/pathogens14090930","url":null,"abstract":"<p><p>Leishmaniasis is difficult to control due to clinical and vector diversity associated with the complex life cycle of <i>Leishmania</i> parasites, which are transmitted by sandflies. This study investigated the presence of <i>Leishmania</i> DNA in sandfly vectors, their blood meal sources, and their distribution in relation to environmental and climatic variables in four municipalities in Piauí state, Brazil. Between 2020 and 2022, sandflies were collected, morphologically identified, and analyzed for the presence of parasite DNA and blood meal sources (PCR, sequencing). Climate data were correlated with the density of collected insects. Among the 10,245 specimens collected, <i>Lutzomyia longipalpis</i> (54.87%) and <i>Nyssomyia whitmani</i> (30.41%) were the most abundant in the collection areas. <i>Leishmania braziliensis</i> DNA was detected in <i>Lu. longipalpis</i>, while <i>L. braziliensis</i> and <i>Leishmania infantum</i> DNAs were recovered from <i>Ny. whitmani. Homo sapiens</i> was the main blood meal source (~73%). Vector density was associated with humidity, temperature, and precipitation in Teresina and Pedro II, with significant results for <i>Ny. whitmani</i>. In conclusion, <i>Lu. longipalpis</i>, widely adapted to anthropized environments, can act as a potential vector of the etiological agent of cutaneous leishmaniasis in Teresina and Oeiras. In Pedro II, the detection of <i>L. infantum</i> DNA in <i>Ny. whitmani</i> suggests a possible role of this species in the transmission cycle of visceral leishmaniasis, reinforcing the complex ecoepidemiology of <i>Leishmania</i> spp. in Piauí.</p>","PeriodicalId":19758,"journal":{"name":"Pathogens","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12472939/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145177174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Swine Practitioner Practices on Oral Fluid Sampling in U.S. Swine Farms: A Nationwide Survey.","authors":"Xiaomei Yue, Mickey Leonard, Margret Tavai-Tuisalo'o, Sasidhar Malladi, Mariana Kikuti, Claudio Marcello Melini, Pam Zaabel, Marie R Culhane, Cesar A Corzo","doi":"10.3390/pathogens14090940","DOIUrl":"10.3390/pathogens14090940","url":null,"abstract":"<p><p>Oral fluid sampling has been widely adopted in swine health surveillance, offering an effective and cost-effective method for monitoring endemic and emerging diseases. This study characterized oral fluid sampling practices within U.S. pig production systems. An online questionnaire was conducted between June and October 2023, targeting swine practitioners, to collect data on implementation, usage, sampling protocols, and handling procedures. A total of 67 valid responses were received, representing an estimated 58M growing pigs and 3.9M sows. Nearly all respondents (99%) reported being familiar with or using oral fluid sampling for diagnostic purposes. The median of ropes hung per barn was two (interquartile range [IQR]: 1; 4), with 68% using one rope per two pens. The median of pens sampled per barn was six (IQR: 4; 10). Pigs typically accessed the rope for a median of 20 min (IQR: 17.5; 30). Sampling frequency varied by farm types. Half of gilt-development-unit (GDU) respondents collected samples monthly. When submitting samples to the veterinary diagnostic laboratories, pig age (91%) was the most frequently included information. This study reveals the widespread and varied adoption of oral fluid sampling, highlighting the need for standardized collection procedures to support consistent interpretation and improve reliability for detecting emerging pathogens.</p>","PeriodicalId":19758,"journal":{"name":"Pathogens","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12473141/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145177372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Update on Ophthalmic Implications of Highly Pathogenic Avian Influenza A (H5N1) Virus.","authors":"Timothy Kaftan, Nam V Nguyen, Jack Begley, Tolulope Fashina, Jessica Carag, Steven Yeh","doi":"10.3390/pathogens14090932","DOIUrl":"10.3390/pathogens14090932","url":null,"abstract":"<p><strong>Introduction: </strong>Highly Pathogenic Avian Influenza (HPAI) A(H5N1) represents a growing public health challenge, given broadening zoonotic vectors, with a previously reported human mortality rate of roughly 50%. Late March 2024 marked the start of a new outbreak of HPAI A(H5N1) in the United States. While offering unique public health challenges, this outbreak also provides insight into clinical presentation and ocular involvement implications, transmission vectors, and the implementation of successful surveillance strategies.</p><p><strong>Objectives: </strong>This review seeks to highlight current and historical outbreak trends, transmission and ocular tropism significance, and strategies to mitigate viral spread.</p><p><strong>Methods: </strong>A comprehensive narrative literature review was completed using PubMed database as well as local, federal, and international public health press releases.</p><p><strong>Discussion: </strong>The 2024 US outbreak of H5N1 demonstrates the unique adaptability of the virus. Traditionally transmitted to humans via infected poultry, this outbreak marks the first confirmed case of dairy cow-transmitted human infection. Unlike many past H5N1outbreaks, the majority of patients in the current US outbreak have presented with conjunctivitis either alone or alongside systemic symptoms. This ocular-specific disease manifestation offers new clinical and screening implications. Awareness of ophthalmic involvement among physicians and public health organizations can help guide screening candidates and identify potential infections.</p>","PeriodicalId":19758,"journal":{"name":"Pathogens","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12472830/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145177458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the Virome of Nile Tilapia (<i>Oreochromis niloticus</i>) Using Metagenomic Analysis.","authors":"Amira Ezzat, Ahmed Abd El Wahed, Arianna Ceruti, Amel M El Asely, Mohamed Shawky Khalifa, Andrew D Winters, Uwe Truyen, Adel A Shaheen, Mohamed Faisal","doi":"10.3390/pathogens14090935","DOIUrl":"10.3390/pathogens14090935","url":null,"abstract":"<p><p>Nile tilapia (<i>Oreochromis niloticus</i>) is an indispensable source of high-quality protein worldwide. Along with the exponential expansion of tilapia aquaculture, several novel pathogenic viruses have emerged, and some cause significant economic losses. Unfortunately, there is scarce information on the biology and epidemiology of these viruses. This exploratory metagenomic study used Oxford Nanopore Technology (ONT) sequencing to profile the virome compositions of both wild and farmed Nile tilapia across five regions in Egypt. The Nile tilapia virome was dominated by two double-stranded DNA bacteriophages, <i>Muvirus mu</i> and <i>M. sfmu</i>, which constituted 79.8% of the detected sequences. Eukaryotic viruses, including members of the families <i>Amnoonviridae</i>, <i>Peribunyaviridae</i>, and <i>Baculoviridae</i>, were also identified. Two giant DNA viruses known to infect <i>Acanthamoeba</i> spp., <i>Mollivirus</i> sp., and <i>Pandoravirus</i> sp. were identified in the spleen virome of tilapia from a single sampling site. The diversity analysis showed no significant differences among tissue types or sampling sites. Phylogenetic analyses were performed on a single virus detected of potential pathogenicity, an amnoonvirus. The analyses demonstrated that the detected virus is a member of the family <i>Amnoonviridae</i> and placed it alongside members of the <i>Tilapinevirus</i> genus. The virus, however, was distinct from the other two members in the genus: <i>T. tilapae</i> and <i>T. poikilos</i>. This study underscores the usefulness of ONT in providing a foundational understanding of the Nile tilapia virome.</p>","PeriodicalId":19758,"journal":{"name":"Pathogens","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12472937/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145176722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global Research Trends on Major Pathogenic Enteric Viruses (1990-2024): A Bibliometric Analysis of Epidemiology, Transmission, and Public Health Impact.","authors":"Mohammad Alotaibi, Hanan Al-Khalaifah, Assia Bouhoudan","doi":"10.3390/pathogens14090938","DOIUrl":"10.3390/pathogens14090938","url":null,"abstract":"<p><p>Pathogenic enteric viruses are a leading cause of gastroenteritis-related mortality worldwide. However, the architecture of this research field remains poorly quantified. This bibliometric analysis provides a comprehensive overview of 35 years of global scientific output on major enteric viruses, such as rotavirus, norovirus, astrovirus, sapovirus, and non-polio enteroviruses, to map trends, methodological developments, and geographic disparities. We conducted a systematic search of PubMed and Scopus (1990-2024), identifying 10,017 records. After deduplication and eligibility screening, a final corpus of 8320 publications was analyzed using Bibliometrix (Biblioshiny 5.0) in R (version 4.3.0) and VOSviewer (Version 1.6.20). We found that scientific production grew steadily (CAGR = 5.84%), reaching its peak in 2021. The field is characterized by profound thematic and geographic disparity: rotavirus dominated the literature (56.3% of publications), followed by norovirus (30.8%), while other viruses were severely underrepresented (<9% each). Geographically, output was highly concentrated, with the top five countries (the USA, China, Japan, India, and Brazil) producing 92.4% of the publications. In contrast, high-burden regions, such as sub-Saharan Africa and Latin America, contributed only 7.6%. Genomic sequencing gained prominence, being cited in over 26.2% of publications from 2020 to 2024, reflecting a methodological shift accelerated by the application of wastewater-based epidemiology during the COVID-19 pandemic. In conclusion, while genomic tools and environmental monitoring are transforming enteric virus research, its progress is hampered by deep and persistent inequalities. These include a narrow focus on rotavirus and a significant disparity between regions with high disease burdens and those with high research outputs. Closing this gap requires targeted investments in equitable collaboration, local genomic capacity, and integrated public health interventions combining vaccination, WASH, and One Health strategies.</p>","PeriodicalId":19758,"journal":{"name":"Pathogens","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12472404/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145177205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pangenomic Characterization of <i>Campylobacter</i> Plasmids for Enhanced Molecular Typing, Risk Assessment and Source Attribution.","authors":"Lucas Harrison, Sampa Mukherjee, Cong Li, Shenia Young, Qijing Zhang, Shaohua Zhao","doi":"10.3390/pathogens14090936","DOIUrl":"10.3390/pathogens14090936","url":null,"abstract":"<p><p>Plasmid-mediated dissemination of antimicrobial resistance (AMR) and virulence genes plays a critical role in enhancing the adaptive potential of <i>Campylobacter</i> spp. While <i>Campylobacter</i> plasmids of concern are commonly classified as pTet, pVir, pCC42 or a large plasmid encoding a T6SS (pT6SS), existing classification systems often lack the resolution to capture intra-group diversity. Here we demonstrate a plasmid typing approach with enhanced discriminatory power that categorizes these major plasmid groups into discrete subgroups and strengthens risk-assessment investigations. Pangenomic analysis of 424 <i>Campylobacter</i> plasmid sequences revealed 30 distinct plasmid groups. The four major groups above accounted for 74.3% of the dataset. Within these major groups, 177 plasmid type-specific loci were used to define 16 subgroups. pTet plasmids were subdivided into 5 subgroups, with subgroup 3 enriched in <i>C. coli</i>. pVir plasmids formed 3 subgroups, with only subgroup 3 harboring the <i>tet(O)</i> genes. The 5 pCC42 subgroups displayed <i>Campylobacter</i> species specificity while the 3 pT6SS subgroups encoded distinct AMR profiles. This high-resolution typing approach provides a unified and scalable method to characterize <i>Campylobacter</i> plasmid diversity and identifies genetic markers critical for pathogen surveillance, source attribution and mitigation strategies employed to safeguard human and animal health.</p>","PeriodicalId":19758,"journal":{"name":"Pathogens","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12472675/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145177261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Silent Carriers: The Role of Rodents in the Emergence of Zoonotic Bacterial Threats.","authors":"Shereen Basiouni, Alfonso J Rodriguez-Morales, Awad A Shehata, Phelipe Magalhães Duarte","doi":"10.3390/pathogens14090928","DOIUrl":"10.3390/pathogens14090928","url":null,"abstract":"<p><p>Rodents are recognized as significant reservoirs for a broad range of zoonotic pathogens, including bacteria, viruses, and parasites, many of which have substantial implications for human and animal health. The intensifying interaction between humans and rodent populations, fuelled by urbanization, climate change, and global trade, has amplified the risk of zoonotic disease transmission. This review compiles and examines current knowledge on key rodent-borne bacterial diseases, including leptospirosis, rat-bite fever, plague, salmonellosis, tularemia, Lyme disease, rickettsioses, Babesiosis, and associated parasitic infections such as toxoplasmosis and Chagas disease. Each disease is analyzed in terms of its etiology, transmission, clinical manifestations, diagnostic tools, and treatment options, with a particular focus on the impact of environmental changes. Emphasizing a One Health perspective, this work highlights the importance of interdisciplinary approaches to the surveillance, prevention, and control of rodent-borne zoonoses, particularly in the context of increasing climate variability and anthropogenic pressures.</p>","PeriodicalId":19758,"journal":{"name":"Pathogens","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12472809/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145177277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"H5N1 Clade 2.3.4.4b: Evolution, Global Spread, and Host Range Expansion.","authors":"Klaudia Chrzastek, Carolin M Lieber, Richard K Plemper","doi":"10.3390/pathogens14090929","DOIUrl":"10.3390/pathogens14090929","url":null,"abstract":"<p><p>Highly pathogenic avian influenza viruses (HPAIVs) of the H5 subtype pose a continuous threat to animal and public health due to their zoonotic potential, rapid evolution, and ability to spread across continents. Since the emergence of the A/goose/Guangdong/1/96 (GsGD) H5 lineage in 1996, several clades have caused devastating outbreaks in poultry and wild bird populations, occasionally resulting in human infections. Of the many clades that have evolved, only three-clades 2.2, 2.3.2.1, and most recently 2.3.4.4b-have demonstrated the ability to spread globally. The 2.3.4.4b clade has raised significant concern due to its continuous geographic expansion, establishment in new ecosystems, including Antarctica, and increasing reports of mammalian infections, including companion animals, marine mammals, and livestock. Recently, cow-to-cow and cow-to-human transmission marked a paradigm shift in the epidemiology of avian influenza and emphasized the need for continued surveillance. This review summarizes the historical emergence, global spread, and molecular evolution of H5 HPAIVs with a specific focus on the recent expansion of clade 2.3.4.4b and its capacity for mammalian spillover.</p>","PeriodicalId":19758,"journal":{"name":"Pathogens","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12472894/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145177237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Repellent Activity of the Botanical Compounds Thymol, Carvacrol, Nootkatone, and Eugenol Against <i>Amblyomma sculptum</i> Nymphs.","authors":"Mayara Macêdo Barrozo, Emilly Faria Santos, Haile Dean Figueiredo Chagas, Rafael Assunção Carvalho, Isabela Santos Silva, Ariel de Souza Oliveira, Laura Cristina Ferreira Faria, Ana Lúcia Coutinho Teixeira, Viviane Zeringota, Hermes Ribeiro Luz, Lorena Lopes Ferreira, Caio Monteiro","doi":"10.3390/pathogens14090926","DOIUrl":"10.3390/pathogens14090926","url":null,"abstract":"<p><p>This study evaluated the repellent activity of the botanical compounds thymol, carvacrol, nootkatone, and eugenol (5%), as well as the combination of 2.5% nootkatone + 2.5% eugenol, against <i>Amblyomma sculptum</i> nymphs under laboratory and field conditions. In contact bioassays, carvacrol and nootkatone showed the highest mean repellency rates (94.5% and 93.7%), followed by thymol and eugenol (90.2% and 87.2%). The combination (nootkatone + eugenol) resulted in 92.8% repellency, with 100% efficacy in some evaluation periods. The repellency of 7% DEET (positive control) was 82.2%. Nootkatone 5% and the combination (nootkatone + eugenol) were also tested in a Y-tube olfactometer, showing repellency rates of 86.1% and 72.2%, respectively, both higher than 7% DEET (69.4%). In field trials, volunteers wore treated socks and walked through an area naturally infested with nymphs. A significant reduction (<i>p</i> < 0.05) in tick counts was observed in the treated groups (about five unfed nymphs) compared to the control (about 40 unfed nymphs). Cumulative efficacy exceeded 85% in both treatments. In the cost simulation, the estimated cost of a 100 mL formulation containing 5% nootkatone was USD 50.8, while the combination (nootkatone + eugenol) presented a cost USD 28.6, representing a 44% reduction with no loss of efficacy in field conditions. These results indicate that all compounds tested showed repellent activity in the laboratory. Nootkatone has high repellent activity, and its combination with eugenol is a promising and more economically viable alternative for tick repellency.</p>","PeriodicalId":19758,"journal":{"name":"Pathogens","volume":"14 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12472471/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145177200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}