Background Data on tick bites and erythema migrans (EM) in eastern Austria remain limited despite ongoing changes in tick ecology. Methods A survey was conducted including 3005 dermatology patients in eastern Austria. Patients reported tick bites within the preceding year, subsequent EM and associated symptoms. Demographic data were collected, including age, sex, and urbanization level. Associations between tick bites, EM and demographic and geographic variables were analyzed using descriptive statistics, chi-square tests and logistic regression, including flexible spline modeling of age. Results Tick bites were reported by 430 patients (14.3%) and were more frequent in Lower Austria than in Burgenland (15.0% vs. 11.4%, p = 0.024). Tick-bite frequency was similar across urban, suburban and rural areas. Tick bites were more frequent in women (p < 0.001) and showed a significant non-linear association with age (p < 0.001). Within age groups, women aged 60 – 69 had significantly more tick bites than men in the same age group (p < 0.001). EM developed in 7% of patients following a tick bite, corresponding to approximately 1% of the entire cohort. EM was more frequent in Burgenland than in Lower Austria (11.3% vs. 6.6%, p = 0.008). Conclusion Tick bites were common in this eastern Austrian outpatient cohort. The risk of being bitten varied with sex, age and region, with women more frequently affected overall. EM developed in 7% of patients with tick bites, indicating a higher manifestation index than previously reported in Austrian data. These findings support continued surveillance and targeted prevention in endemic regions.
Spotted fever group (SFG) Rickettsia spp. are emerging zoonotic pathogens transmitted by ixodid and argasid ticks. Despite the recognized importance of ticks as vectors in Central Asia, data on the prevalence and genetic diversity of SFG Rickettsia in Uzbekistan remain scarce. This study aimed to determine minimum infection rates (MIR) and phylogenetic relationships of SFG Rickettsia circulating in ticks parasitizing domestic animals across five regions of Uzbekistan. Ticks (n = 12,769) were collected from 8632 domestic animals (cattle, sheep, goats, horses, camels, donkeys, and poultry) between 2021 and 2026. Ticks were screened either individually or in pools of 4-5 adult specimens, with each pool comprising ticks of the same species and sex collected from the same individual host, using real-time PCR. Among the qPCR-positive pools, 26 were randomly selected for conventional singleplex PCR targeting the gltA, ompA, ompB, and sca4 genes. Fourteen selected positive pools yielded amplicons suitable for sequencing, generating 25 partial gene sequences in total (gltA, n = 9; ompA, n = 3; ompB, n = 9; sca4, n = 4), which were subjected to bidirectional Sanger sequencing and phylogenetic analysis. Positive amplicons were sequenced and phylogenetic trees constructed using maximum likelihood with 1000 bootstrap replicates. Twelve ixodid and one argasid tick species were identified. Overall tick infestation prevalence in animals was 36.5% (95% CI: 35.5-37.6%). Rickettsia DNA was detected in 2331 ticks from positive pools (global MIR: 18.3%; 95% CI: 17.6-18.9%). Highest MIRs were found in Hyalomma scupense (25.1%), Rhipicephalus turanicus (23.4%) and Rhipicephalus pumilio (21.7%). Regional MIRs ranged from 0.77% (Syrdarya) to 31.8% (Jizzakh). gltA, ompA, ompB, and sca4 partial sequences of "Candidatus Rickettsia barbariae" and Rickettsia massiliae were identified for the first time in Uzbekistan. Phylogenetic analyses confirmed their placement within distinct SFG Rickettsia clades. This study provides baseline data on the diversity and distribution of SFG Rickettsia in Uzbekistan. Rickettsia DNA was detected in Hy. scupense, Hyalomma anatolicum, Hyalomma asiaticum, Rh. turanicus, Rhipicephalus sanguineus sensu lato, Rhipicephalus annulatus, Rh. pumilio, Argas persicus, and Haemaphysalis sulcata. The first detection of "Ca. R. barbariae" and R. massiliae in Uzbekistan underscores the need for integrated One Health surveillance of tick-borne rickettsioses in domestic animals and humans.
Japanese spotted fever (JSF) is a tick-borne disease caused by Rickettsia japonica, a member of the spotted fever group rickettsiae. Recently, Japan has experienced a marked increase in JSF cases, with endemic regions expanding from western to eastern areas. However, the specific tick species carrying R. japonica in these newly affected eastern regions, as well as the factors influencing this geographic dissemination, remain unclear. In this study, we investigated the tick species carrying R. japonica and assessed the potential involvement of wild boars (Sus scrofa) in the dispersal of these ticks in Ibaraki Prefecture, a newly recognized JSF-endemic area in eastern Japan. A total of 4549 questing ticks were collected and pooled into 747 samples; 289 samples (38.7%) tested positive for Rickettsia DNA. Among these positive samples, R. japonica was detected only in Haemaphysalis hystricis. Nineteen wild boars captured near the tick sampling sites exhibited heavy infestations with H. hystricis, suggesting that wild boars are important blood-meal hosts for this tick species. Additionally, H. hystricis carrying R. japonica were collected from wild boars. In contrast, R. japonica was not detected in any biological samples collected from wild boars. These results suggest that H. hystricis is a potential vector of R. japonica in Ibaraki Prefecture and that wild boars may potentially transport H. hystricis carrying R. japonica. However, this study found no evidence that wild boars act as reservoirs or amplifying hosts. Given the recent increase and geographic expansion of wild boar populations in the prefecture, continued surveillance of the distribution of H. hystricis is warranted.
Vector-borne diseases pose a growing challenge to public health. Effective surveillance, interdisciplinary cooperation in line with the One Health approach, and prevention and control strategies are therefore essential to reduce the risk of future outbreaks and burden of disease in the long term. Identifying and investigating sentinels can help in this regard. In this study, 537 red fox (vulpes) spleen samples from three regions in Germany (Berlin, Brandenburg, Arnsberg administrative region) were tested for Anaplasmataceae and Rickettsia spp. using PCR. Only 3% of the samples (n = 15) tested positive for Anaplasmataceae. Candidatus Neoehrlichia sp. (FU98) was detected most frequently (1.7%; n = 9), followed by Anaplasma phagocytophilum (0.9%, n = 5) and a previously undescribed Ehrlichia sp. genotype (0.4%; n = 2). Rickettsia spp. were not detected. To our knowledge, this is the first finding of Candidatus Neoehrlichia sp. (FU98) in Germany, and our study has also revealed the presence of a previously unknown Ehrlichia species (Ehrlichia sp. ex European carnivore) that is not closely related to E. canis. Anaplasma phagocytophilum was detected in all three regions at low prevalence. Candidatus Neoehrlichia sp. (FU98) in Berlin and Brandenburg but not in Arnsberg. Further studies are necessary to isolate this new agent, as well as to investigate its geographic distribution and host range. Sequences representing an unknown Ehrlichia species were found in one fox sample each in Berlin and Brandenburg. Further investigations are needed regarding its phylogenetic position, vector and host affiliation.
BACKGROUND:Differentiating Lyme neuroborreliosis (LNB) from Bell's palsy (BP) in adults with peripheral facial palsy remains challenging. We aimed to develop and internally validate clinical decision support tools for European adults to reduce unnecessary lumbar punctures and support timely treatment. METHODS:We conducted a nationwide retrospective cohort study including adults (≥18 years) with facial palsy and confirmed LNB or BP from two Danish cohorts (2015-2024). All patients underwent lumbar puncture. Data were extracted from medical records, and 29 candidate predictors were selected for analysis. The dataset was randomly split into training (80%) and test (20%) sets. Key predictors were identified using random forest and used to develop a decision tree. Analyses were repeated excluding serum Borrelia burgdorferi (Bb) IgG as results may be unavailable at presentation. RESULTS:We included 683 patients (422 LNB, 261 BP); 23% of LNB patients were initially misdiagnosed as BP. Key predictors of LNB were radicular pain, serum Bb IgG positivity, symptom duration ≥7 days, and forest/grass exposure. The resulting decision tree showed high performance (accuracy 0.93; sensitivity 0.93; specificity 0.94). It could reduce lumbar punctures by 40% and initially missed LNB to 8%, while 9% of BP would still undergo lumbar puncture. Excluding serum Bb IgG, radicular pain and symptom duration ≥10 days remained key predictors, with similar performance (accuracy 0.93; sensitivity 0.92; specificity 0.93). CONCLUSIONS:We developed two accurate tools using a small set of variables, with radicular pain emerging as an important predictor. External validation is required before clinical implementation and is underway through a European collaboration.
Understanding the factors driving individual exposure to tick bites is essential for predicting tick-borne disease risk. We analyzed data from a 6-day international orienteering competition held in July 2018 in the forests of Moselle, France, involving over 1200 competitors per day and 418 monitored participants. Using generalized linear mixed models, we assessed the influence of environmental and behavioral factors (racing round, race length, exposure time, departure time and repellent use) on the occurrence of tick bites in general, and specifically on the occurrence and the number of Ixodes ricinus nymph bites. Unaccounted individual-level variation was incorporated into the models through a random effect of orienteer ID. Tick bite risk was significantly influenced by racing round, departure time, race length, and repellent use, but not by exposure duration. Departure time was one of the strongest predictors, with early starters facing higher bite probabilities—which might be due to local depletion of questing ticks by earlier competitors and reduced tick activity later in the day. Race length also predicted tick bite risk, possibly reflecting differences in participant density along courses rather than distance alone. Repellent use provided limited protection. Importantly, individual identity accounted for a large portion of total variance, exceeding that of other tested factors, and recent prior tick bite history strongly predicted future bites during the last race. These findings highlight the need to further quantify inter-individual variability and to consider this variability when modeling tick bite risk.
Ixodes ricinus (Family Ixodidae), a widespread generalist tick in Europe, feeds on a large number of host species and acts as a major vector for various tick-borne pathogens. Immature stages of I. ricinus are often found feeding on various bird species, but questions remain open regarding ecological interactions between these organisms especially in relation to potential life-stage specific infestation of juvenile birds. Utilizing ongoing monitoring schemes during the breeding season in northern Germany, we studied the occurrence of ticks on birds caught in two independent forest areas during three subsequent seasons (2022-2024) to study relationships between tick infestation and bird-specific traits (i.e., age, body condition). Tick infestation differed significantly between bird species and we observed significant interactions with bird age and body condition. Adult birds showed lower tick burdens in comparison to juvenile conspecifics and tick infestation showed complex interactions with body condition; highlighting multiple mechanisms are most likely influencing our results. Through morphological identification of attached ticks, we could show that I. ricinus larva and nymphs differ in their interactions with bird traits, with only the number of larvae differing with bird age and neither life-stage alone correlating with bird body condition. Taken together, we supported life-stage specific infestation as a potential driver of higher tick burdens in juvenile birds and show how standardized monitoring can provide insight into these interactions.
Ticks are important vectors of emerging viruses, and China's ecological landscapes may influence the transmission dynamics of tick-borne viruses (TBV). In 2021, a total of 2867 ticks collected from Inner Mongolia, Hebei, Hunan, and Hainan provinces were subjected to metagenomic sequencing to characterize TBV diversity. A total of eleven TBVs were identified, comprising three members of the family Phenuiviridae (severe fever with thrombocytopenia syndrome virus, Lihan tick virus, Dabieshan tick virus), three belonging to Nairoviridae (Huangpi tick virus 1, Shanxi tick virus 2, Henan tick virus), one in Chuviridae (Wuhan tick virus 2), one in Rhabdoviridaes (Wuhan tick virus 1), and three unclassified viruses (Hubei tick virus 2, Bole tick virus 4, and Tacheng tick virus 7). Viral composition varied significantly across tick species and geographic regions, with phylogenetic analysis revealing distinct regional clustering patterns. Notably, Lihan tick virus was detected for the first time in Hunan Province, Bole tick virus 4 was identified in argasid ticks from Inner Mongolia for the first time, and a novel lineage of severe fever with thrombocytopenia syndrome virus was discovered in Shijiazhuang, Hubei Province. These findings underscore substantial TBV diversity shaped by tick species and geographic origin, emphasizing the necessity for ongoing surveillance to guide the development of targeted prevention and control strategies.
Ticks are known vectors of pathogens affecting animals and humans globally. However, there are gaps in knowledge regarding the diversity of ticks and tick-borne pathogens (TBPs) affecting wildlife in South Africa. This study aimed to determine the occurrence, diversity, and distribution of ticks and TBPs in cheetahs and lions from different localities in South Africa using morphological and molecular techniques. Thirty-three blood samples and 94 ticks were opportunistically collected from 30 cheetahs and four lions in 12 conservation facilities. DNA was extracted from 88 ticks and 33 blood samples. Six tick specimens were submitted to the Gertrud Theiler Tick Museum as reference vouchers. The CO1 and 16S rRNA genes were targeted for tick identification, while the 18S rRNA gene was targeted for the identification and characterisation of Apicomplexan parasites (Babesia, Theileria, Hepatozoon spp.). Nine species belonging to the genera Amblyomma, Haemaphysalis, Hyalomma, and Rhipicephalus were identified, with Haemaphysalis elliptica (59/94; 62.8%) identified as the most abundant species. Sequencing results for the CO1 and 16S rRNA genes were consistent with the morphological identification, except the CO1 sequence of FEL 09dT, which was morphologically identified as R. afranicus, but clustered between the reference sequences of R. linnaei and R. turanicus. Analysis of the 18S rRNA sequences from host blood and ticks revealed 98-100% similarity with published sequences of Babesia lengau, Hepatozoon felis, Hepatozoon ingwe, Hepatozoon luiperdjie, and uncharacterized Babesia and Hepatozoon species. This study demonstrates that wild carnivores in South Africa harbour diverse tick species and TBPs, most of which have unknown host range, transmission, and pathogenicity. Therefore, further studies are crucial to unravel the risk they may pose to the ecosystem.
Knowledge about the epidemiology of Lyme borreliosis in Austria remains limited. We conducted a nationwide cross-sectional study among blood donors from all Austrian provinces to assess the exposure to Borrelia burgorferi sensu lato. A total of 1841 serum samples from blood donors aged between 18 and 69 years were tested for Borrelia-specific IgG and IgM. Associations with age, sex, province and the residential altitude were assessed for both the one-tier and two-tier methods. IgG seroprevalence was 14% for one-tier and 7% for the two-tier. A consistent increase in age was observed for both approaches. Using the 20-29-year age group as reference, the strongest association was observed in individuals aged 60-69 years. The IgG positivity was higher among males than females for both the one-tier and two-tier tests. Regional analysis revealed substantial variation in IgG seroprevalence, with the lowest prevalence recorded in Tyrol and the highest in Carinthia. These differences were not attributable to age distribution. An additional analysis revealed a correlation between the seroprevalence and the altitude of residence. IgM seroprevalence did not differ significantly between the one-tier and two-tier approaches (7% and 6%), and no age-, sex-, or region-related trends were identified. Our findings demonstrate demographic and regional differences in exposure to Borrelia burgdorferi. Higher altitude of residence is associated with reduced exposure to the spirochetes. The findings emphasize the importance of Lyme borreliosis surveillance and help identify the groups and areas most likely to profit from targeted prevention.
The ecological factors shaping the distribution of key tick vector species remain only partially understood. We analysed the spatial patterns of three medically important ticks, Dermacentor reticulatus, Ixodes persulcatus, and Ixodes ricinus in Latvia, using extensive field records from a single survey combined with environmental predictors harmonised to a 1 km spatial resolution. We pursued two complementary objectives: (i) to model and map the spatial distribution of three epidemiologically important tick species in Latvia, and (ii) to evaluate whether a joint species distribution modelling framework provides additional inferential or predictive benefit compared with single‑species models.The joint species distribution modelling analysis did not yield stable residual association estimates across fitting approaches, so subsequent inference and spatial prediction focused on single-species distribution models using Random Forest, Boosted Regression Trees, and Support Vector Machines under spatial cross-validation. Model performance differed among species, with highest predictive accuracy for I. persulcatus (mean AUC ≈ 0.93), moderate performance for I. ricinus (≈ 0.81), and lower but above-random performance for D. reticulatus (≈ 0.69).Temperature- and moisture-related predictors, including satellite-derived indicators of seasonal land surface temperature dynamics, were consistently influential. Response curves revealed strong non-linear and threshold relationships, with D. reticulatus showing relatively narrow climatic optima, I. persulcatus associated with cooler and more humid conditions, and I. ricinus exhibiting broader environmental tolerances. Final habitat suitability maps showed clear spatial differentiation: I. ricinus had the broadest area of high suitability, I. persulcatus displayed a more regionally structured pattern, and D. reticulatus was restricted to patchier areas.Our results suggest that, at the spatial scale considered, strong environmental filtering dominated species distributions, limiting the added value of joint modelling relative to more stable single‑species approaches. Together, these results provide a spatially robust and ecologically grounded distribution assessment for ticks in Latvia. The findings support public-health surveillance, identify regions of elevated potential exposure, and highlight the need to investigate additional ecological mechanisms, beyond species interactions, that shape tick communities across the Baltic region.
Leucokinin (LK) has been functionally characterised in ticks, but its anatomical organisation remains poorly understood. Here, we investigate the anatomical and molecular organisation of LK and its receptor (LKR) in the tick Ixodes ricinus using molecular and anatomical approaches. We functionally identified the I. ricinus LKR and confirmed its activation by LK. Quantitative PCR revealed lkr transcripts across life stages and in peripheral tissues, including salivary glands. Within the synganglion, LK was localised to a defined population of medial protocerebral neurosecretory neurons by immunohistochemistry and confirmed by in situ hybridisation. Their axons project to the dorsolateral perineurium of the synganglion, suggesting a neurohaemal release site supported by ultrastructural evidence. LKR immunoreactivity was detected in a limited subset of neuronal somata within the synganglion. In peripheral tissues, LK-immunoreactive axons innervate salivary glands, mainly type II acini and occasionally type III acini. LKR immunoreactivity was detected in the corresponding acinar cells. This spatial organisation of axonal projections and receptor localisation suggests a role for LK in the regulation of acinar activity. Together, these findings refine the anatomical organisation of LK in I. ricinus and provide a framework for future functional studies.
Ticks are vectors of a wide range of pathogens, relevant to both veterinary and public health. Although tick surveillance is frequently conducted in the Netherlands, data on tick-borne pathogens in free-living herbivores remains limited, leaving the impact of these pathogens on animal health poorly understood. This study aimed to characterise tick species and determine seroprevalence and infection prevalence of selected tick-borne pathogens in large herbivores at the Oostvaardersplassen nature reserve and questing ticks collected in the area. Between September 2023 and December 2024, blood was opportunistically sampled from Heck cattle, Konik horses, and red deer culled for population control, and questing ticks were collected. Serum, blood, and pooled tick samples were tested for tick-borne encephalitis virus (TBEV), Anaplasma spp., A. phagocytophilum, Babesia spp., B. microti, B. caballi and Theileria equi, Borrelia burgdorferi s.l., and B. miyamotoi using serological and molecular methods. In total, 2617 questing Ixodes ricinus were collected. In red deer (n = 177), seropositivity was 6.2% for TBEV, prevalence was 58.9% for A. phagocytophilum, and 53.4% for Babesia spp. (predominantly B. divergens and B. cf. odocoilei). Corresponding values in cattle (n = 36) were 0%, 14.3%, and 3.6%, and in horses (n = 89) 0%, 1.2%, and 0%, respectively. In questing ticks, TBEV (0.04%), Babesia spp. (1.5%; mainly B. venatorum and B. cf. odocoilei; excluding B. microti), B. microti (1.9%), B. burgdorferi s.l. (8.5%), B. miyamotoi (1.8%), and A. phagocytophilum (1.1%) were detected. This study provides new evidence of TBEV circulation and confirms active transmission of multiple tick-borne pathogens at Oostvaardersplassen. These findings support integrating systematic tick surveillance into existing monitoring programmes at nature reserves, strengthening One Health informed disease surveillance to safeguard animal and public health.
BACKGROUND:Tick-borne diseases are an important public health concern worldwide. In Japan, tick-associated rash illness (TARI) has been frequently reported following bites from Amblyomma testudinarium. However, the epidemiological characteristics and risk factors associated with TARI are not well understood. This study aimed to characterize tick bite cases and identify predictors associated with the development of TARI. METHODS:We analyzed 523 tick bite cases reported by medical clinics in Hyogo and Shizuoka Prefectures, Japan, between 2019 and 2024. Data on demographics, clinical manifestations, tick bite history, and tick characteristics were collected. Although tick bite cases associated with different tick species were recorded, statistical analyses were restricted to A. testudinarium-associated cases because most TARI cases occurred in this group. Associations with TARI were evaluated using comparative analyses and multivariable logistic regression. RESULTS:Most tick bite cases were associated with A. testudinarium (84.5%). The average age of individuals was 54 years. Increasing age was independently associated with higher TARI risk (adjusted odds ratio [aOR] = 1.06 per year; 95% confidence interval [CI] 1.04-1.10). A strong exposure-response relationship was observed between prior tick bites and TARI risk: patients reporting three or more previous tick bites had 7.0-fold higher odds of developing TARI (95% CI 3.04-16.80) compared with first-time exposures. Tick biological characteristics were also significant predictors: bites from larval ticks were associated with 8.52-fold higher odds of TARI than bites from nymphal ticks (95% CI 1.48-58.10), and moderately engorged ticks carried 3.14-fold higher odds compared with unfed ticks (95% CI 1.23-8.71). Season was also associated with TARI occurrence, with significantly lower odds observed in summer and autumn compared with spring. CONCLUSION:History of repeated tick bites and biological characteristics of the removed ticks seem to be major factors associated with TARI risk, supporting the hypothesis that TARI may represent an immunologically mediated hypersensitivity reaction. Given the broader distribution of A. testudinarium in Southeast Asia, clinical awareness and detailed exposure assessment are needed beyond Japan to improve diagnosis and guide public health strategies for at-risk populations across the region.
INTRODUCTION:Lyme disease (LD) is the most frequently reported vector-borne disease in the Czech Republic (CR). The risk of infection is present throughout the entire country. This study analyzes trends in the number of cases and the incidence of LD in the CR between 2018 and 2024. METHODS:The study analyzes data from the Information System of Infectious Diseases, which records notifiable infections in accordance with national legislation, including cases of LD classified under code A69.2 according to the International Classification of Diseases, 10th Revision (ICD-10). RESULTS:Between 2018 and 2024, a cumulative total of 26,183 LD cases were reported in the CR, with annual incidence ranging from 27.0 to 44.5 per 100,000 population. The female-to-male ratio was 54% versus 46%. The highest incidence was observed in the 45-74 age groups (45-54 years: 40.5/100,000; 55-64 years: 50.3/100,000; 65-74 years: 50.7/100,000). Among pediatric populations, the peak incidence occurred in the 5-9 age group (49.5/100,000). Significant regional differences were observed across the CR, with the highest incidence in the Vysocina Region (100.1/100,000) and the South Bohemian Region (71.1/100,000). The average hospitalization rate was 18.4%. A total of eight deaths attributable to LD were recorded during the study period (2018-2024). CONCLUSION:Even during the COVID-19 pandemic, LD maintained interannual variability in its occurrence. In 2021, the lowest incidence in the past 25 years was recorded in the CR. The increase in incidence observed in 2024 indicates a return to pre-pandemic levels.
Tick-borne bacterial and protozoal pathogens are a major threat to equine health worldwide. In Austria, studies on pathogens such as piroplasms, Anaplasma phagocytophilum and Borrelia spp. in horses are scarce and do not cover the countrywide horse population. To address this, blood samples from horses without prior record of infection with tick-borne pathogens (n = 588) were tested for the presence of Theileria equi, Babesia caballi or A. phagocytophilum DNA by PCR and for specific antibodies against these pathogens and Borrelia burgdorferi with commercially available assays. While no DNA of B. caballi could be amplified, specific anti-B. caballi antibodies were detected in eleven horses (1.9% by ELISA). DNA of T. equi was amplified in twelve horses. In two horses DNA of Babesia canis was detected. Anti-T. equi antibodies were detected in the T. equi PCR-positive horses and one of the B. canis-PCR-positive animals. No A. phagocytophilum-DNA could be amplified, while anti-Ap antibodies were detected in 42.7% (IFAT) resp. 57.3% (ELISA) of 544 horses, and 44.2% had specific anti-B. burgdorferi antibodies. Of the A. phagocytophilum-seropositive horses, 57.8% were also positive for B. burgdorferi. In total, 28% of the horses were positive for two or three pathogens. Common significant associations with infections included pasturing and housing, and, for T. equi, also place of birth/import. High infection rates with A. phagocytophilum and B. burgdorferi indicate a significant exposure of Austrian horses for ticks and tickborne pathogens in general, and, together with the T. equi infections detected throughout the country, highlight the potential risk of transmission to vectors with further infections of horses and subsequent disease after tick bites during pasturing or outdoor activities, and should alert veterinarians to include these etiologies as differential diagnoses in clinically overt cases.
Members of the phylum Chlamydiota are obligate intracellular bacteria increasingly recognized across a wide range of arthropod hosts, including ticks. In this study, we investigated the diversity and distribution of chlamydiae in Ixodes ricinus ticks and their potential association with Lyme borreliosis spirochetes. A total of 250 questing nymphal and female I. ricinus ticks were collected from three recreational sites in Vienna, Austria. Individual tick guts were screened for chlamydiae using pan-Chlamydiota PCR assays targeting the 16S rRNA gene, followed by sequencing for taxonomic identification. The presence and abundance of Borrelia burgdorferi sensu lato were quantified by specific qPCR to evaluate potential co-occurrence patterns. Chlamydiota DNA was detected in ticks from all investigated areas, with prevalence varying according to geography and developmental stage. Phylogenetic analyzes revealed high chlamydial diversity within the gut microbiome, predominantly comprising members of the metagenomic family MCF-D, followed by Parachlamydiaceae, Endochlamydiaceae, and Parasimkaniaceae. A positive, albeit not statistically significant, association between Chlamydiota and Borrelia was also observed. These findings indicate that the I. ricinus gut microbiome harbours a diverse assemblage of chlamydiae, suggesting potential ecological and functional relevance. Overall, our study highlights the importance of tissue-specific, single-tick analyzes for elucidating microbiome complexity and advances current understanding of Chlamydiota diversity in the tick vector. Further experimental and multi-omics studies are warranted to elucidate the biological roles of these bacteria in tick physiology and pathogen infection dynamics.
Climate change is driving the expansion of various tick species in North America. In this context, it is essential to ensure that vector populations can be effectively detected and monitored in both emerging and endemic regions. The objective of this study was to characterize the methods used for sampling questing hard ticks of the family Ixodidae and synthesize current knowledge on their effectiveness. A scoping review was conducted and 56 studies published before October 2024 were included in the analysis. Overall, 63% of the studies were conducted in North America and 9% in Europe. The majority of the studies concerned Ixodes spp. (63%). Most studies on Ixodes spp. and Dermacentor spp. examined cloth-based methods such as dragging, flagging, and sweeping, while CO₂ traps were most frequently studied for Amblyomma spp. Only seven studies quantified the proportion of the estimated tick population sampled using collection methods. Overall, a single dragging passage was estimated to capture only a small proportion of the questing nymph population, approximately 6% (5.9–6.3%). Several technical, environmental, and climatic factors may influence sampling effectiveness, including temperature, sampling period, and cloth type. Methodological variability across studies limited comparability and hindered the establishment of standardized guidelines. Nevertheless, we can conclude that no single collection method emerged as a gold standard, and that a combination of methods may be required. Based on these findings, we provide evidence-based recommendations for the selection of tick sampling methods based on different objectives, tick genus, life stage, and environmental and climatic factors.
Some species of the Borrelia genus can infect animals, producing clinical signs and resulting in production losses. Borrelia theileri is the causative agent of bovine borreliosis and is transmitted by hard ticks, primarily Rhipicephalus microplus. The aim of this study was to detect B. theileri in R. microplus and cattle in some areas of the Córdoba department in Caribbean Colombia. In 2021 and 2022, ticks and whole blood were collected from Bos taurus and Bos indicus cattle in the department of Córdoba, Colombia. DNA was extracted from 913 ticks and 122 cattle blood samples were collected. Screening was performed using a Borrelia genus-specific qPCR for the 16S rRNA gene; positive samples underwent PCR for the 16S rRNA and flaB genes. The amplified products were Sanger sequenced. Alignments were performed, and phylogenetic trees were constructed using IQTREE2 and visualized and edited using ITOL. Borrelia spp. was detected in 13.9 % (17/122) of the cattle samples by qPCR. Using conventional PCR the 16SrRNA gene was detected in 23.5% (4/17) of the samples, while the flaB gene was not detected. Phylogenetic analyses of the 16SrRNA gene in cattle showed clustering with Borrelia sp. (MZ564265), B. theileri (MN619805) and close association with other B. theileri sequences (KAT KF569941, LC656247, MW562684, DQ872186, DQ872186). The ticks were taxonomically identified as R. microplus. The 16SrRNA gene of Borrelia spp. was detected by qPCR in 15.5% (35/225) of the samples. With conventional PCR, the 16SrRNA gene was detected in 37% (13/35) of the samples, and the flaB gene was detected in 5.7% (2/35). Sequencing was performed using flaB gene sequences of good quality. Phylogenetic analysis of the flaB gene showed that our sequences were grouped with Borrelia sp. (EF141022) and B. theileri (ON191583, C5 MG601737, KF569936). This is the first detection of B. theileri in ticks and the second in cattle in Colombia.
