Ticks and Tick-borne Diseases最新文献

{"title":"Risk factors for α-Gal syndrome: A case-control study exploring the role of tick bites in French Guiana","authors":"Aude Valois ,&nbsp;Jonas Le Forestier ,&nbsp;Evrard Baduel ,&nbsp;Geneviève Guillot ,&nbsp;Théo Blaise ,&nbsp;Pierre Couppié ,&nbsp;François Delon ,&nbsp;Loïc Epelboin","doi":"10.1016/j.ttbdis.2026.102607","DOIUrl":"10.1016/j.ttbdis.2026.102607","url":null,"abstract":"<div><div>α-Gal Syndrome (AGS) is an IgE-mediated allergy to galactose-α-1,3-galactose (α-Gal), a carbohydrate found in non-primate mammalian tissues. AGS manifests as delayed anaphylactic reactions following the consumption of mammalian meat or exposure to products containing α-Gal. Recent studies confirm tick bites may be a key sensitizing factor. This study aimed to investigate tick bites and other potential risk factors for AGS in French Guiana.</div><div>A retrospective case-control study was conducted at the Cayenne Hospital Center between January 2021 and October 2022. Cases were defined as adults with clinical symptoms of anaphylaxis after consumption of mammalian meat or α-Gal–containing products, and with detectable anti–α-Gal IgE (&gt; 0.1 kUA/L). Controls were patients consulting for other IgE-mediated allergies, without any symptoms after mammalian meat consumption. Data were collected through a standardized questionnaire and specific IgE assays. Bivariate and multivariate analyses were performed to identify associated risk factors. Confounding biases were limited using a propensity score.</div><div>A total of 54 patients (18 cases, 36 controls) were included. All AGS cases reported at least one tick bite in French Guiana, versus only 22% of controls (Adjusted OR = 170.250; 95% CI [5.981 – 3.528 × 10^6], <em>p</em> &lt; 0.001). Blood group B or AB was less frequent in cases (0% vs 19%, AOR = 0.227; 95% CI [0 – 8.899], <em>p</em> = 0.488). Atopy was not associated with AGS.</div><div>In this tropical setting, tick bites, especially from the more anthropophilic <em>Amblyomma cajennense</em> sensu stricto, appear to be a major risk factor for AGS, along with forest-related occupational exposure. These findings support the assumption that ticks are probably at least the main vector of symptomatic sensitization to α-Gal in French Guiana.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102607"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic diversity of Coxiella burnetii in ticks from the Republic of Guinea","authors":"Karifa Camara ,&nbsp;Alissa Hammoud ,&nbsp;Hadiatou Mariama Diallo ,&nbsp;Adama Zan Diarra ,&nbsp;Almamy Ousmane Deen Camara ,&nbsp;Lanceï Kaba ,&nbsp;Mamadou Cellou Balde ,&nbsp;Pierre-Edouard Fournier ,&nbsp;Florence Fenollar ,&nbsp;Oleg Mediannikov","doi":"10.1016/j.ttbdis.2025.102597","DOIUrl":"10.1016/j.ttbdis.2025.102597","url":null,"abstract":"<div><div><em>Coxiella burnetii</em> is a worldwide zoonotic pathogen responsible for Q fever. Ticks act as both potential reservoirs and vectors of <em>C. burnetii,</em> playing a critical role in maintaining its natural transmission cycle. Nevertheless, the vector competence of ticks in transmitting <em>C. burnetii</em> remains a topic of ongoing scientific debate. This study aims to investigate the genetic diversity of <em>C. burnetii</em> in ixodid ticks from the Republic of Guinea. Ixodid ticks were collected from cattle, goats, sheep, and dogs across eight locations of the Republic of Guinea in 2023. Ticks were identified to the species level using both morphological and molecular methods. Screening for <em>C. burnetii</em> was performed using two quantitative polymerase chain reaction assays targeting the IS1111 and IS30 sequences. Positive samples were subsequently genotyped using multispacer sequence typing (MST) with 10 spacer regions. A total of 946 ticks were collected screening revealed the presence of <em>C. burnetii</em> DNA in 5.4 % (52/946) of ticks. The main tick species positive for <em>C. burnetii</em> were <em>Rhipicephalus sanguineus</em> s.l. 19.2 % (10/52), <em>Rhipicephalus microplus</em> 17.3 % (9/52) and <em>Hyalomma truncatum</em> 13.4 % (7/52). Genotyping of 38.4 % (20/52) of the <em>C. burnetii</em>-positive specimens identified five different genotypes, including four novel ones (MST 86, MST 87, MST 88, and MST 89) and one previously described genotype, MST 61. Molecular identification of the 52 ticks positive for <em>C. burnetii</em> DNA revealed 12 tick species. This study underscores the Republic of Guinea as a hotspot for <em>C. burnetii</em> genetic diversity, with novel genotypes suggesting localized evolution or cross-species transmission.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102597"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145953729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mapping ticks (Acari: Argasidae, Ixodidae) and informing local public action: Insights from the United Kingdom Tick Surveillance Scheme (2021-2024)","authors":"Kayleigh M Hansford ,&nbsp;Faye V Brown ,&nbsp;Sarah M Biddlecombe ,&nbsp;Jonathan Yardley ,&nbsp;Emmanuella O Luce ,&nbsp;Sara Gandy ,&nbsp;Colin J Johnston ,&nbsp;Nicola Jones ,&nbsp;Anthony J Abbott ,&nbsp;Beth Mackenzie ,&nbsp;Anna Rance ,&nbsp;Meghan-Louise Meban ,&nbsp;Andrew J D Nelson ,&nbsp;Christopher Williams ,&nbsp;Dominic Mellor ,&nbsp;Amanda Semper ,&nbsp;Christina Petridou ,&nbsp;Rachel Pudney ,&nbsp;Jolyon M Medlock","doi":"10.1016/j.ttbdis.2025.102579","DOIUrl":"10.1016/j.ttbdis.2025.102579","url":null,"abstract":"<div><div>The Tick Surveillance Scheme (TSS) is a citizen science initiative which relies on public and professional submissions to monitor tick species distribution, seasonal exposure, and host associations across the United Kingdom (UK). During the period 2021–2024, 3182 tick records were received and 27 tick species were detected. The data confirm that <em>Ixodes ricinus</em>, the primary vector for Lyme disease and Tick-borne encephalitis, remains the most common tick in the UK. The TSS continues to detect imported tick species, underscoring the risk of novel pathogens entering the country, with new species like <em>Hyalomma excavatum</em> and <em>Rhipicephalus pulchellus</em> reported for the first time. The scheme also provides crucial evidence of non-endemic species like <em>Hyalomma marginatum</em> being found on hosts without history of foreign travel, although establishment risk is currently considered low. In addition to updated species distribution maps, a new tick-bite incidence metric has been developed and translated into a heat map for England and Wales. Updated regularly, this enables targeted public health interventions and awareness campaigns at the local authority level, providing a proxy for potential tick exposure. Tick submissions are likely underrepresented from Scotland and Northern Ireland, suggesting a need to strengthen outreach in these areas to improve data accuracy.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102579"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145913801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response to the critique on the TerL-based PCR by Zimmermann et al. (2025)","authors":"Jinyu Shan ,&nbsp;Tanja Mijatovic ,&nbsp;Louis Teulières ,&nbsp;Martha R.J. Clokie","doi":"10.1016/j.ttbdis.2025.102593","DOIUrl":"10.1016/j.ttbdis.2025.102593","url":null,"abstract":"","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102593"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145913833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dichotomous key to larvae of the genus Amblyomma (Parasitiformes: Ixodidae) in Brazil, with morphological description and redescription of the larval stage of 30 Amblyomma species","authors":"Thiago F. Martins ,&nbsp;Adriano Pinter ,&nbsp;Vera L.F. de Camargo-Neves ,&nbsp;Agustín Estrada-Peña ,&nbsp;Pablo H. Nunes ,&nbsp;Fábio Barbieri ,&nbsp;Kátia M. Famadas ,&nbsp;Marcelo B. Labruna","doi":"10.1016/j.ttbdis.2025.102590","DOIUrl":"10.1016/j.ttbdis.2025.102590","url":null,"abstract":"<div><div>Ticks of the genus <em>Amblyomma</em> are of great medical and veterinary importance in Brazil, where they regularly parasitize wild and domestic animals and will bite humans that enter rural and forest areas for work and recreation purposes. This study provides morphological descriptions and redescriptions of the larval stage of 30 <em>Amblyomma</em> species occurring in Brazil, using morphometry, chaetotaxy and porotaxy. A dichotomous key with important characteristics illustrated by light and scanning electron microscopy was constructed for larvae of 31 species of <em>Amblyomma</em> from Brazil, including <em>Amblyomma monteiroae</em>, a recently described endemic species. The larvae of the following 11 species are described for the first time: <em>Amblyomma aureolatum, Amblyomma cajennense, Amblyomma coelebs, Amblyomma fuscum, Amblyomma goeldii, Amblyomma humerale, Amblyomma incisum, Amblyomma latepunctatum, Amblyomma naponense, Amblyomma pseudoconcolor</em>, and <em>Amblyomma scalpturatum</em>. In addition, the larvae of the following 19 species are redescribed: <em>Amblyomma auricularium, Amblyomma brasiliense, Amblyomma calcaratum, Amblyomma dissimile, Amblyomma dubitatum, Amblyomma geayi, Amblyomma longirostre, Amblyomma nodosum, Amblyomma oblongoguttatum, Amblyomma ovale, Amblyomma pacae, Amblyomma parkeri, Amblyomma parvum, Amblyomma romitii, Amblyomma rotundatum, Amblyomma sculptum, Amblyomma tigrinum, Amblyomma triste</em>, and <em>Amblyomma varium</em>. Together with the recent description of <em>A. monteiroae</em>, these results formed the basis for the formulation of a dichotomous key encompassing 31 <em>Amblyomma</em> species occurring in Brazil. Undoubtedly, the results of this study will assist future fieldwork aimed at identifying <em>Amblyomma</em> larvae collected from hosts and the environment.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102590"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145913779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular detection of medically important rickettsiae, including Rickettsia prowazekii in Rhipicephalus appendiculatus and Hyalomma rufipes: A microbiome perspective","authors":"OV Anyango ,&nbsp;OW Aool ,&nbsp;M Lukindu ,&nbsp;T Nakayiki ,&nbsp;J Lutwama ,&nbsp;JK Kayondo ,&nbsp;CD Phillips ,&nbsp;J Lutomiah ,&nbsp;J Mutisya ,&nbsp;CL Brelsfoard ,&nbsp;MG Onyango","doi":"10.1016/j.ttbdis.2025.102596","DOIUrl":"10.1016/j.ttbdis.2025.102596","url":null,"abstract":"<div><div>The East African region hosts more than 50 % of Africa livestock and 9 % of global cattle, creating an ideal environment for ticks to thrive and transmit pathogens. Little is known of the full spectrum of tick-associated bacterial pathogens that circulate in the vast pastoralist-intense regions of East Africa, the range of the pathogens and their genetic relationships. To define this, we need to first delineate the microbial composition of the medically and veterinary important East African tick species. This study focused on the likely vectors of <em>Orthonairovirus haemorrhagiae</em> in Kenya and Uganda, specifically <em>H. rufipes</em> and <em>R. appendiculatus</em>. To characterize the bacterial microbiome associated with these two tick species, the V3–V4 hypervariable region of the 16S rRNA gene was sequenced from a total of 25 <em>R. appendiculatus</em> and 24 <em>H rufipes</em> specimens using the Illumina MiSeq platform. Microbial abundance and diversity were subsequently analysed to assess the composition and structure of their bacterial communities. We observed a richer and balanced bacterial microbiome profile among the <em>H. rufipes</em> compared to that of the <em>R. appendiculatus</em>, which was mainly dominated by <em>Coxiella</em>-like endosymbionts. Furthermore, a few bacterial taxa were unique to each sampling site, while several were common across all sampling sites. This study identified several medically important <em>Rickettsia</em> species, including <em>R. aeschlimannii, R. conorii,</em> and, for the first time, <em>R. prowazekii</em>, the causative agent of epidemic typhus, in <em>H. rufipes</em> sampled from Northeast Kenya. Furthermore, our findings demonstrate that <em>R. africae</em> exhibits a broad tick host tropism. Our present findings provide insights into the microbial community of medically important tick species of East Africa. The observation of a significant level of <em>Coxiella</em>-like endosymbionts in <em>R. appendiculatus</em> warrants an investigation into their transmissibility and impacts on the transmission of other pathogens. The identification of <em>R. prowazekii</em> in <em>H. rufipes</em> suggest that <em>R. prowazekii</em> is broadening its host tropism in Kenya.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102596"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145913804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seroprevalence and risk factors for Anaplasma marginale seropositivity in cattle in California between 2010 and April 2023","authors":"SY Chen ,&nbsp;A Hill ,&nbsp;W Jackson ,&nbsp;M Saunders ,&nbsp;B Munk ,&nbsp;J Foley ,&nbsp;S Gassama ,&nbsp;G Maier","doi":"10.1016/j.ttbdis.2026.102604","DOIUrl":"10.1016/j.ttbdis.2026.102604","url":null,"abstract":"<div><div>The objectives of this study were to estimate prevalence of <em>A. marginale</em> infection in cattle in California and to identify potential risk factors for infection including weather effects. We considered individual-level prevalence the percentage of positive individual test results and submission-level prevalence the percentage of submissions from the same owner at the same time with at least one animal testing positive for <em>Anaplasma</em>. A total of 3684 <em>Anaplasma</em> test results from 773 submissions to the California Animal Health and Food Safety Laboratory between January 2010 and April 2023 were used in this study. Time series analysis and generalized estimating equations (GEEs) were used to analyze the data. Abundance of <em>Dermacentor</em> ticks in California was mapped. The overall true prevalence of <em>Anaplasma</em> infection at the individual level was 23.7% (95% CI: 22.3 – 25.2%) with a submission-level prevalence of 38.3% (95% CI: 34.9 – 41.8%) in cattle in California. A seasonal change in seroprevalence was observed in time series analysis, with lower seroprevalence in wet seasons than in dry seasons. Higher odds of <em>Anaplasma</em> positivity were found in cattle two years of age or older, beef cattle, with lower average ambient temperatures in the dry season, and higher average ambient temperatures in the wet season in GEEs.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102604"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular characterization of Candidatus Anaplasma camelii in Tunisian dromedaries based on partial groEL and gltA sequence data","authors":"Valentina Chisu ,&nbsp;Rosanna Zobba ,&nbsp;Angela Peruzzu ,&nbsp;Laura Giua ,&nbsp;Giovanna Chessa ,&nbsp;Ben Smida Boubaker ,&nbsp;Carla Cacciotto ,&nbsp;Emanuela Bazzoni ,&nbsp;Zeinab Sinaei ,&nbsp;Giovanna Masala ,&nbsp;Alberto Alberti","doi":"10.1016/j.ttbdis.2026.102606","DOIUrl":"10.1016/j.ttbdis.2026.102606","url":null,"abstract":"<div><div><em>Candidatus</em> Anaplasma camelii is a poorly identified <em>Anaplasma</em> species reported in dromedary camels (<em>Camelus dromedarius</em>). Although sequences from <em>Ca.</em> A. camelii had previously been detected in Tunisia, they were not accurately identified or taxonomically classified at that time. This study provides the first comprehensive molecular characterization of <em>Ca</em>. A. camelii in Tunisian dromedaries using a combined sequencing approach targeting 16S rRNA, the <em>groEL</em> gene and the <em>gltA</em> gene. Out of 229 dromedaries blood samples analysed 45 (19.7%) tested positive for <em>Anaplasma</em> spp. by 16S rRNA PCR. The presence of <em>Ca.</em> A. camelii was subsequently confirmed by <em>groEL</em> and <em>gltA</em> amplification. Phylogenetic analyses revealed a well-supported monophyletic clade grouping Tunisian isolates with strains previously reported in Egypt and in the United Arab Emirates (UAE). This study expands the known geographic distribution of <em>Ca.</em> A. camelii by introducing novel molecular data, thereby enhancing our understanding of its genetic diversity and evolutionary relationships. Findings highlight the importance of multi-gene molecular surveillance to elucidate the epidemiology of emerging <em>Anaplasma</em> species in Northern Africa.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102606"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Borrelia burgdorferi s.l. and its genetic variability in five European countries","authors":"Michal Chvostáč ,&nbsp;Sabrina Hepner ,&nbsp;Gabriele Margos ,&nbsp;Yuliya M. Didyk ,&nbsp;Michal Stanko ,&nbsp;Bronislava Víchová ,&nbsp;Barbara Mangová ,&nbsp;Veronika Rusňáková Tarageľová ,&nbsp;Andreas Sing ,&nbsp;Volker Fingerle ,&nbsp;Markéta Derdáková","doi":"10.1016/j.ttbdis.2026.102605","DOIUrl":"10.1016/j.ttbdis.2026.102605","url":null,"abstract":"<div><div>The <em>Borrelia burgdorferi</em> s.l. complex is known for its complex genome and significant genetic variability. We used multilocus sequence typing (MLST) to study the genetic variability of <em>Borrelia</em> in five European countries: Slovakia, Croatia, Ukraine, Finland and Bulgaria. We compared the prevalence, genospecies spectrum and genetic variability of <em>Borrelia</em> in 4013 questing <em>Ixodes ricinus</em> ticks. The highest prevalence of <em>Borrelia</em> was found in Slovakia (26.7 %) and Ukraine (22 %), while in Finland and Bulgaria the prevalence was found to be 12.4 % and 7.2 %, respectively. Genospecies diversity was the highest in Croatia with seven identified genospecies. This was in contrast to Finland and Bulgaria where only three species were detected. In phylogenetic trees <em>Borrelia</em> species clustered according to species designation. <em>Borrelia afzelii</em> and <em>Borrelia garinii</em> were the most prevalent amongst the <em>Borrelia</em> species and were found in all collection regions. <em>Borrelia garinii</em> but also <em>B. afzelii</em> isolates did not show a phylogeographic pattern in minimum spanning trees. Based on MLST<em>, Borrelia lusitaniae</em> isolates from Slovakia, Croatia, Ukraine and Bulgaria belonged to the “northern European” clade, which differs genetically from <em>B. lusitaniae</em> isolates found in southern Portugal and northern Africa. <em>Borrelia bavariensis</em> from the Slovak Republic and Ukraine firmly clustered with Western European isolates. Besides questing ticks, Edible dormice (<em>Glis glis</em>) earlobe biopsies were analyzed as <em>B. afzelii</em> clustering with other European isolates of this species. In this study we report the first evidence of <em>Borrelia</em> genospecies in the following countries: <em>Borrelia spielmanii, B. bavariensis</em> and <em>B. lusitaniae</em> in Ukraine; <em>B. spielmanii</em> in Bulgaria; <em>Borrelia burgdorferi</em> s.s<em>., B. spielmanii, B. lusitaniae</em> and <em>B. bavariensis</em> in Croatia.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102605"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145999342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disentangling complex disease ecology networks: Using structural equation modelling to quantify the direct and indirect effects of deer on Lyme borreliosis hazard","authors":"Sara L. Gandy ,&nbsp;Fernanda Sánchez-Rodríguez ,&nbsp;William McLellan ,&nbsp;Fanny Olsthoorn ,&nbsp;Marianne C. James ,&nbsp;Paul C.D. Johnson ,&nbsp;Roman Biek ,&nbsp;Hein Sprong ,&nbsp;Manoj Fonville ,&nbsp;Caroline Millins ,&nbsp;Ken J. Forbes ,&nbsp;Alan S. Bowman ,&nbsp;Jaboury Ghazoul ,&nbsp;Lucy Gilbert","doi":"10.1016/j.ttbdis.2025.102595","DOIUrl":"10.1016/j.ttbdis.2025.102595","url":null,"abstract":"<div><div>Quantifying the strengths of interactions in complex vector-borne disease ecological systems is challenging. Yet, overcoming this challenge is fundamental for understanding the ecological mechanisms shaping disease hazard. Here we quantified the strengths of the hypothesised direct and indirect mechanistic pathways through which deer affect ticks and one of the Lyme borreliosis pathogens, <em>Borrelia afzelii,</em> by conducting a combined analysis of three previously published datasets from 39 sites across Scotland. Structural equation modelling revealed that, as predicted, deer had a strong positive overall effect (direct and indirect pathways combined) on questing <em>Ixodes ricinus</em> nymph density and a weak, non-significant, negative overall effect on <em>B. afzelii</em> prevalence. This resulted in an overall weak, non-significant, positive effect of deer on <em>B. afzelii</em> hazard (the density of infected nymphs)<em>,</em> indicating that their negative effect on <em>B. afzelii</em> prevalence was weaker than their positive effect on questing nymph density<em>.</em> A key novelty of this study was being able to tease apart the direct and indirect pathways for each of these overall effects and demonstrating that they were primarily driven by direct mechanisms, such as deer driving nymph density. Although deer negatively affected rodent abundance, the hypothesised indirect pathways from deer to ticks and pathogen, acting through vegetation and/or rodents, were weak. This could result from low densities of rodents relative to deer in Scotland, consistent with Scotland having among the lowest nymphal Lyme borreliosis pathogen prevalences in Europe. Applying the methodological framework used in this study would be useful for teasing apart complex interactions in other vector-borne disease systems.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102595"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145913738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}