Ticks and Tick-borne Diseases最新文献

{"title":"An insight into the ovary and midgut transcriptome of Dermacentor nitens tick","authors":"Stephen Lu ,&nbsp;Christopher F. Bosio ,&nbsp;Vinicius Andrade-Silva ,&nbsp;Ially de Almeida Moura ,&nbsp;Giancarlo Bomfim Ribeiro ,&nbsp;Markus Berger ,&nbsp;Wendell Marcelo De Souza Perinotto ,&nbsp;Itabajara da Silva Vaz Junior ,&nbsp;Lucas Tirloni","doi":"10.1016/j.ttbdis.2025.102600","DOIUrl":"10.1016/j.ttbdis.2025.102600","url":null,"abstract":"<div><div>The tropical horse tick, <em>Dermacentor nitens</em>, is a one-host hard tick widely distributed across tropical and subtropical regions of the Americas, where it primarily parasitizes horses and occasionally cattle and other livestock. This species is of veterinary importance due to its role as a vector of <em>Babesia caballi</em>, the causative agent of equine piroplasmosis. Despite its significance, genomic resources for <em>D. nitens</em> remain scarce, limiting molecular and functional studies. Here, we present the most comprehensive transcriptome assembly of <em>D. nitens</em> to date, encompassing midgut and ovary transcriptomes during the rapid phase of blood feeding. Using deep sequencing approaches, we identified and annotated a large repertoire of transcripts expressed during blood feeding and reproduction, processes central to tick survival and pathogen transmission. To further facilitate gene discovery in <em>D. nitens</em>, we conducted orthology searches against annotated transcripts from the genomes of <em>Dermacentor albipictus, Dermacentor andersoni, Dermacentor silvarum, Dermacentor variabilis, Hyaloma asiaticum, Haemaphysalis longicornis, Ixodes scapularis, Ixodes persulcatus, Rhipicephalus microplus,</em> and <em>Rhipicephalus sanguineus</em>. Our dataset provides new insights into midgut and ovary physiology, including genes associated with blood meal digestion and oogenesis, which are critical for reproduction and life cycle progression. These findings expand the molecular toolkit available for <em>D. nitens</em>, enabling future studies on tick physiology, evolution, and vector competence. Moreover, this resource offers a framework for comparative analyses with other <em>Dermacentor</em> species of medical relevance, thereby advancing our understanding of conserved biological mechanisms underlying feeding, reproduction, and pathogen transmission.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102600"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145913751","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 circulating in soft ticks infesting colonial breeding seabirds along the Portuguese coast","authors":"Ana Cláudia Norte ,&nbsp;Maria Sofia Núncio ,&nbsp;Maria Teresa Luz ,&nbsp;Paulo Parreira ,&nbsp;Jorge Pereira ,&nbsp;Adriana Sofia Domingues ,&nbsp;Maria Inês Laranjeiro ,&nbsp;Sara Veríssimo ,&nbsp;Ivo dos Santos ,&nbsp;Catarina Santos Lopes ,&nbsp;Filipe Rafael Ceia ,&nbsp;Vítor Hugo Paiva ,&nbsp;Jaime Albino Ramos ,&nbsp;Isabel Lopes de Carvalho","doi":"10.1016/j.ttbdis.2025.102591","DOIUrl":"10.1016/j.ttbdis.2025.102591","url":null,"abstract":"<div><div>Seabirds are hosts of several tick species, but there is little information on their infestation by soft ticks and pathogens they harbour is available. In this study, we evaluated soft tick infestation in gull chicks from two breeding colonies in Portugal and assessed the prevalence of anti-Borrelia antibody in adults gull and shearwaters from these colonies, as well as from two additional urban colonies. The prevalence of infestation by <em>Ornithodorus maritimus</em> ticks in gull chicks varied between (17.6 %) in three yellow legged gull (<em>Larus michahellis</em>) and 84.8 % in the Audouin’s gull (<em>Ichthyaetus audouinii</em>), with a mean infestation intensity of 4.50 ticks per infested yellow-legged gull chick and 5.59 ticks per infested Audouin’s gull chick. All ticks, except one, were at the larval stage. Infestation prevalence was significantly higher at Deserta Island (south Portugal) compared to Berlenga Island. Of the 133 ticks screened, only two tested positive for <em>Borrelia</em>: one for <em>Borrelia turdi</em> (from a yellow legged gull) and one <em>Borrelia mayonii</em> from a Audouin’s gull. However, only one gene could be sequenced for each. No relapsing fever Borrelia species were detected. Although differences among colonies were only marginally significant, Deserta Island exhibited higher anti-<em>Borrelia</em> antibody prevalence than Berlenga Island. No significant differences were observed between bird species. These findings highlights the need for further investigation into Borrelia- soft tick- seabird interactions, and the potential infection risks associated with gull breeding habitats, particularly in areas of human-wildlife contact.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102591"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145913761","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":"Corrigendum to \"A review on the role of birds as disseminators of ticks, with special emphasis on Hyalomma species and Crimean-Congo haemorrhagic fever virus\" [Ticks and Tick-borne Diseases, 16 (2025), 102535].","authors":"Gergő Keve, Attila D Sándor, Sándor Hornok","doi":"10.1016/j.ttbdis.2025.102587","DOIUrl":"10.1016/j.ttbdis.2025.102587","url":null,"abstract":"","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":" ","pages":"102587"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145994593","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":"Comparison and complete mitogenomes of two morphologically similar but ecologically different tick species, Ixodes arboricola and Ixodes lividus (subgenus Pholeoixodes)","authors":"Sándor Hornok ,&nbsp;Paulina Lesiczka ,&nbsp;Tim Warbroek ,&nbsp;Tijs J.M. van den Bosch ,&nbsp;Andor Pitó ,&nbsp;Gergő Keve ,&nbsp;Nóra Takács ,&nbsp;Jenő Kontschán ,&nbsp;Attila D. Sándor","doi":"10.1016/j.ttbdis.2025.102589","DOIUrl":"10.1016/j.ttbdis.2025.102589","url":null,"abstract":"<div><div><em>Ixodes arboricola</em> and <em>Ixodes lividus</em> are ornithophilic tick species. The former is typically associated with tree-hole dwelling birds, while the latter is a host-specific parasite of sand martins (<em>Riparia riparia</em>). These two tick species share important morphological characters that make them difficult to identify when they are collected from atypical hosts, such as birds of prey. Despite this, high resolution digital pictures have not been reported to compare <em>I. arboricola</em> and <em>I. lividus</em>, nor was their complete mitogenome reported. The aim of this study was to compensate for this lack of illustrations and sequence data. Nymphs and females of <em>I. arboricola</em> and <em>I. lividus</em> were used for morphological comparison, and one specimen of each species to generate mitogenome sequences.</div><div>The results showed that females of these two species are different in the shape of their scutum, porose areas, the length of basis capituli, palps, coxae, genital pore, anal groove and tarsus I. On the other hand, nymphs of <em>I. arboricola</em> and <em>I. lividus</em> can be distinguished according to their cervical grooves, cornuae, auricular ridges and spiracular plates. The mitochondrial genome size was 14,539 and 14,536 bp, for <em>I. arboricola</em> and <em>I. lividus</em>, respectively. The mitogenome sequences of <em>I. arboricola</em> and <em>I. lividus</em> were 91.1% identical to each other. Phylogenetic analysis of <em>Ixodes</em> species showed that <em>I. arboricola</em> and <em>I. lividus</em> are sister species, and cluster together with <em>Ixodes crenulatus</em>/<em>canisuga</em> under strong support.</div><div>In conclusion, results of this study confirmed that the front of the basis capituli is crucial in distinguishing <em>Ixodes</em> species, especially in the subgenus <em>Pholeoixodes</em> where these two species are phylogenetically closest related to <em>I. canisuga</em>. Another phylogenetically relevant morphological character is the scutal surface which is wrinkled (rugose) as a common feature of <em>Pholeoixodes</em> species in the clade of <em>I. arboricola</em> and <em>I. lividus</em> (including <em>I. canisuga, I. rugicollis</em> and <em>I. ariadnae</em>). Although the host ranges of <em>I. arboricola</em> and <em>I. lividus</em> do not substantially overlap, they may transmit some of the shared pathogens. Relevant data indicate that the eco-epidemiological significance of the two ornithophilic tick species studied here may in part be similar and they may play a role in the transmission of rickettsiae, borreliae and viruses of which birds act as reservoirs.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102589"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939355","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":"Comparative transcriptomic insights into ticks infected by alongshan and tick-borne encephalitis viruses","authors":"Cara Leonie Ebert ,&nbsp;Paula Hornauer ,&nbsp;Klaus Jung ,&nbsp;Julia Metzger ,&nbsp;Stefanie C. Becker","doi":"10.1016/j.ttbdis.2025.102592","DOIUrl":"10.1016/j.ttbdis.2025.102592","url":null,"abstract":"<div><div>Ticks are hematophagous ectoparasites and key vectors of a wide range of pathogens, including viruses, bacteria, and protozoa. Climate change and environmental shifts have contributed to the expansion of tick populations and the pathogens they harbor. Ticks rely solely on their innate immune system to combat infections, utilizing mechanisms such as RNA interference, phagocytosis, and antimicrobial peptide expression. However, pathogens have evolved strategies to evade or manipulate these defenses to facilitate their replication and transmission. This study compares the infection dynamics of two tick-borne viruses: <em>Orthoflavivirus encephalitidis</em> (TBEV) and Alongshan virus (ALSV). TBEV, a well-adapted arbovirus, requires both tick and vertebrate hosts for its life cycle and is a major cause of human meningitis and encephalitis across Europe and Asia. In contrast, ALSV appears to be primarily restricted to ticks, with its dependence on vertebrate hosts still unclear. Transcriptomic analyses of <em>Ixodes ricinus</em> ticks revealed distinct gene expression patterns in response to these viruses. TBEV infection primarily regulated genes related to immunity, defense, and digestion—reflecting its adaptation to dual-host environments and acquisition via blood feeding. ALSV infection, however, influenced signaling and infection-related pathways, suggesting a more specialized adaptation to ticks. These findings underscore the differences in immune modulation and metabolic responses between TBEV and ALSV, highlighting the need for further genomic and proteomic studies to enhance our understanding of virus-vector interactions. Such insights could inform strategies for controlling tick-borne diseases and tracking pathogen evolution.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102592"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145913753","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 letter to Rebuttal to Zimmermann et al. (2025) critique of TerL-based PCR","authors":"Manja Zimmermann ,&nbsp;Gabriele Margos ,&nbsp;Christine Hartberger ,&nbsp;Reto Lienhard ,&nbsp;Anna J. Henningsson ,&nbsp;Malin Lager ,&nbsp;Mateusz Markowicz ,&nbsp;Anna-Margarita Schötta ,&nbsp;Andreas Sing ,&nbsp;Benoit Jaulhac ,&nbsp;Per-Eric Lindgren ,&nbsp;Alje P. van Dam ,&nbsp;Joppe W.R. Hovius ,&nbsp;Volker Fingerle","doi":"10.1016/j.ttbdis.2025.102594","DOIUrl":"10.1016/j.ttbdis.2025.102594","url":null,"abstract":"","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102594"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145913814","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":"Nationwide seroprevalence of severe fever with thrombocytopenia syndrome virus in South Korea: Regional patterns and public health implications","authors":"Jongyoun Yi ,&nbsp;Chang-Ki Kim ,&nbsp;Ahreum Kim ,&nbsp;Changhoon Kim ,&nbsp;Maengseok Noh ,&nbsp;Mee Kyung Ko ,&nbsp;Hyun Jin Son ,&nbsp;Kye-Hyung Kim","doi":"10.1016/j.ttbdis.2025.102601","DOIUrl":"10.1016/j.ttbdis.2025.102601","url":null,"abstract":"<div><h3>Objectives</h3><div>Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne viral disease with a high fatality rate and is endemic to East Asia. This study aimed to estimate the seroprevalence of SFTS virus (SFTSV) antibodies in South Korea and analyze regional and demographic variations to guide public health strategies.</div></div><div><h3>Methods</h3><div>We conducted a cross-sectional study using 12,684 residual serum samples from clinics in 17 administrative regions (July 2019–June 2020) using a double-antigen sandwich enzyme-linked immunosorbent assay. Crude and standardized seroprevalence was calculated, and trends were assessed using generalized additive mixed models.</div></div><div><h3>Results</h3><div>The overall crude seroprevalence was 1.63 % and was higher among older adults, particularly those aged 80–99 years (3.03 %). Jeju (2.99 %) and Gangwon (2.28 %) Provinces had the highest standardized seroprevalence. SFTSV seroprevalence did not differ significantly by sex or urban-rural status but was higher in agricultural regions, suggesting occupational exposure as a risk factor.</div></div><div><h3>Conclusions</h3><div>This nationwide estimate of SFTSV seroprevalence highlights high-risk groups, particularly older adults. These findings provide a baseline for surveillance and targeted interventions to mitigate SFTS risk and inform public health strategies in East Asia.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102601"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146013091","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 characterization and identification of a recent discovered genotype of Theileria orientalis (Piroplasmida: Theileriidae) in water buffaloes (Bubalus bubalis) from the Amazon region, Brazil","authors":"João Paulo S. Alves ,&nbsp;Pedro H.C. Rodrigues ,&nbsp;Anisleidy P. Castillo ,&nbsp;Antônio A. Fonseca Junior ,&nbsp;Cairo H.S. de Oliveira ,&nbsp;Rômulo C. Leite ,&nbsp;José D. Barbosa ,&nbsp;Júlia A.G. Silveira","doi":"10.1016/j.ttbdis.2025.102581","DOIUrl":"10.1016/j.ttbdis.2025.102581","url":null,"abstract":"<div><div><em>Theileria orientalis</em> is typically considered a benign protozoan parasite of cattle, although certain genotypes can cause significant economic losses in the livestock industry. Despite Brazil harboring the largest buffalo (<em>Bubalus bubalis</em>) herd in the Western Hemisphere, information regarding <em>T. orientalis</em> infections in this species remains scarce. This study aimed to identify and characterize <em>T. orientalis</em> genotypes circulating in water buffaloes from the State of Pará, located in the Amazon region of Brazil. The major piroplasm surface protein (<em>mpsp</em>) gene of <em>T. orientalis</em> was detected by PCR in 39 out of 271 (14.4 %) buffaloes sampled from two farms in Marajó Island (<em>n</em> = 2) and one farm in the mainland (<em>n</em> = 37). Phylogenetic analysis of <em>mpsp</em> gene sequences revealed the presence of three genotypes: two previously described (Types N1 and N2) and one newly identified genotype (provisionally named Type N4). These findings provide the first evidence of <em>T. orientalis</em> genetic diversity in Brazilian buffaloes and highlight the need for further investigations into its epidemiology and potential tick vectors in South America.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102581"},"PeriodicalIF":3.4,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145769669","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 Hepatozoon spp. in cats living in Germany and other European countries","authors":"Vera Geisen ,&nbsp;Nikola Pantchev ,&nbsp;Yury Zablotski ,&nbsp;Majda Globokar Vrhovec ,&nbsp;Katrin Hartmann ,&nbsp;Michéle Bergmann ,&nbsp;Gastón Moré ,&nbsp;Walter Basso","doi":"10.1016/j.ttbdis.2025.102583","DOIUrl":"10.1016/j.ttbdis.2025.102583","url":null,"abstract":"<div><div><em>Hepatozoon</em> spp. are increasingly reported in cats from Mediterranean countries, but data for Central and Northern Europe remain limited. This study investigated the occurrence and molecular diversity of <em>Hepatozoon</em> spp. in 1357 blood samples from cats living in Germany and other European countries using real-time PCR targeting the 18S rRNA gene. <em>Hepatozoon</em> spp. DNA was detected in 58 cats (4.3 %; 95 %-CI: 3.3–5.5 %). Thirty-seven positive samples were further analyzed by conventional PCR and sequencing. Four sequence types (A-D) were detected. <em>Hepatozoon felis</em> sequences classified within the genogroup I (types A and B) were identified in 33 cats; <em>Hepatozoon silvestris</em> haplotype I (type C) in one cat; and sequences showing 98.5 % identity to <em>H. silvestris</em> (type D) in three cats. Younger cats had a significantly higher infection risk (<em>p</em> = 0.026), while no association with sex was found. Samples submitted for targeted <em>Hepatozoon</em> testing and travel disease screening showed higher positivity rates. Among the 37 molecularly characterized cases, 31 had a known import origin, primarily from Greece, Spain, Cyprus, Italy, Bulgaria, the United Arab Emirates, Jordan, and Turkey. Notably, the <em>H. silvestris</em>-positive cat from Austria had no travel history, representing the first autochthonous case in a domestic cat in Austria. This study highlights the emergence of feline <em>Hepatozoon</em> infections in Europe, involving genetically diverse species. Infections should be considered mainly in cats with Mediterranean origin, travel history, outdoor access, or tick exposure. Identifying vectors responsible for transmission is crucial for implementing effective prevention strategies.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102583"},"PeriodicalIF":3.4,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749458","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":"Lyme arthritis: Demographic characteristics and Borrelia ospA genospecies in synovial fluid. A 17-year cohort study in Sweden","authors":"Katharina Ornstein ,&nbsp;Camilla Broholm ,&nbsp;Ram B. Dessau ,&nbsp;Ann-Cathrine Petersson","doi":"10.1016/j.ttbdis.2025.102582","DOIUrl":"10.1016/j.ttbdis.2025.102582","url":null,"abstract":"<div><div>Lyme arthritis (LA) is a recognized manifestation of Lyme borreliosis in Sweden, but data on the causative <em>Borrelia</em> species are limited. This study aimed to describe the demographics of LA and identify <em>Borrelia burgdorferi</em> sensu lato (<em>B. burgdorferi</em> s.l.) genospecies present in synovial fluid (SF).</div><div>Patient data were collected from the test requisition form accompanying consecutive SF samples submitted to the Clinical Microbiology Laboratory in Lund, Sweden, for <em>Borrelia</em> DNA detection between 2007 and 2023. Detection was performed using 16S rDNA PCR, and genospecies were determined through <em>ospA</em> PCR followed by sequencing.</div><div><em>Borrelia</em> DNA was detected in 323 samples, corresponding to 283 unique patients, from a total of 2353 samples. Species characterization was successful in 213 cases. LA was diagnosed year-round, with approximately half of the cases occurring in youth (0–19 years). Males predominated among adults (≥20 years), though less so among youth. Two species were most common: <em>B. afzelii</em> (104 cases, 49 %) and <em>B. burgdorferi</em> sensu stricto (s.s.) (70 cases, 33 %). <em>B. garinii, B. bavariensis</em>, and <em>B. spielmanii</em> were identified in 21 (9 %), 14 (7 %), and 4 (2 %) cases, respectively.</div><div>In conclusion<em>, B. afzelii</em> was the predominant species in SF. <em>B. burgdorferi</em> s.s. accounted for one-third of LA cases, despite being rarely found in ticks or humans in Sweden. <em>B. spielmanii</em> was detected in four cases, representing the first identification of this species in humans in Sweden and, more broadly, in synovial fluid.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"17 1","pages":"Article 102582"},"PeriodicalIF":3.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145745277","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}