BACKGROUND: Ticks, hematophagous Acari, pose a significant threat by transmitting various pathogens to their vertebrate hosts during feeding. Despite advances in tick genomics, high-quality genomes were lacking until recently, particularly in the genus Ixodes, which includes the main vectors of Lyme disease. RESULTS: Here, we present the genome sequences of four tick species, derived from a single female individual, with a particular focus on the European species Ixodes ricinus, achieving a chromosome-level assembly. Additionally, draft assemblies were generated for the three other Ixodes species, I. persulcatus, I. pacificus, and I. hexagonus. The quality of the four genomes and extensive annotation of several important gene families have allowed us to study the evolution of gene repertoires at the level of the genus Ixodes and of the tick group. We have determined gene families that have undergone major amplifications during the evolution of ticks, while an expression atlas obtained for I. ricinus reveals striking patterns of specialization both between and within gene families. Notably, several gene family amplifications are associated with a proliferation of single-exon genes-most strikingly for fatty acid elongases and sulfotransferases. CONCLUSIONS: The integration of our data with existing genomes establishes a solid framework for the study of gene evolution, improving our understanding of tick biology. In addition, our work lays the foundations for applied research and innovative control targeting these organisms.

• Klíčová slova
• Comparative genomics, Duplication, Hematophagy, Parasite, Retroposition,
• MeSH
• genom * MeSH
• klíště * genetika   MeSH
• molekulární evoluce MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Tick-borne encephalitis virus (TBEV) is flavivirus transmitted to the host via tick saliva which contains various molecules with biological impacts. One of such molecules is Iristatin, a cysteine protease inhibitor from Ixodes ricinus that has been shown to have immunomodulatory properties. To characterize Iristatin in the relation to TBEV, we investigate whether this tick inhibitor has any capacity to influence TBEV infection. Mice were intradermally infected by TBEV with or without Iristatin and the viral multiplication was determined in skin and brain tissues by RT-PCR two and 5 days after infection. The viral RNA was detected in both intervals in skin and increased by time. The application of Iristatin caused a reduction in viral RNA in skin but not in the brain of infected mice 5 days post-infection. Moreover, anti-viral effect of Iristatin on skin was accompanied by a significant decline of interferon-stimulated gene 15 gene expression. The effect of Iristatin on TBEV replication was tested also in vitro in primary macrophages and dendritic cells; however, no changes were observed suggesting no direct interference of Iristatin with virus replication. Still, the Iristatin caused a suppression of Erk1/2 phosphorylation in TBEV-infected dendritic cells and had the anti-apoptotic effect. This is the first report showing that a tick cystatin decreases the viral RNA in the host skin, likely indirectly through creating skin environment that is less supportive for TBEV replication. Assuming, that viral RNA reflects the amount of infectious virus, decline of TBEV in host skin could influence the tick biology or virus transmission during cofeeding.

• Klíčová slova
• Cystatin, Flavivirus, Tick, Tick-borne encephalitis virus, Virus replication,
• MeSH
• antivirové látky farmakologie   MeSH
• cystatiny farmakologie   metabolismus   genetika   MeSH
• dendritické buňky virologie   účinky léků   MeSH
• klíště * virologie   účinky léků   MeSH
• klíšťová encefalitida * virologie   MeSH
• kůže * virologie   MeSH
• makrofágy virologie   MeSH
• mozek virologie   metabolismus   MeSH
• myši MeSH
• replikace viru * účinky léků   MeSH
• RNA virová genetika   MeSH
• slinné cystatiny metabolismus   MeSH
• viry klíšťové encefalitidy * účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antivirové látky MeSH
• cystatiny MeSH
• RNA virová MeSH
• slinné cystatiny MeSH

Ticks obtain a blood meal by lacerating small blood vessels and ingesting the blood that flows to the feeding site, which triggers various host responses. However, ticks face the challenge of wound healing, a process involving hemostasis, inflammation, cell proliferation and migration, and remodeling, hindering blood acquisition. To overcome these obstacles, tick salivary glands produce an array of bioactive molecules. Here, we characterize ixochymostatin, an Ixodes scapularis protein belonging to the trypsin inhibitor-like (TIL) family. It is expressed in multiple developmental stages and in tick salivary glands and acts as a slow and tight-binding inhibitor of chymase, cathepsin G, and chymotrypsin. Predictions for the tertiary structure complex between ixochymostatin and chymase suggest a direct interaction between the inhibitor reactive site loop and protease active sites. In vitro, ixochymostatin protects the endothelial cell barrier against chymase degrading action, decreasing cell permeability. In vivo, it reduces vascular permeability induced by chymase and compound 48/80, a mast cell degranulator agonist, in a mouse model. Additionally, ixochymostatin inhibits the chymase-dependent generation of vasoconstrictor peptides. Antibodies against ixochymostatin neutralize its inhibitory properties, with epitope mapping identifying potential neutralization regions. Ixochymostatin emerges as a novel tick protein modulating host responses against tick feeding, facilitating blood acquisition.

• Klíčová slova
• Chymase, Inhibitor, Ixodes scapularis, Tick saliva, Trypsin inhibitor-like,
• MeSH
• chymasy * metabolismus   chemie   antagonisté a inhibitory   MeSH
• inhibitory trypsinu farmakologie   chemie   metabolismus   MeSH
• kapilární permeabilita * účinky léků   MeSH
• klíště * metabolismus   MeSH
• lidé MeSH
• myši MeSH
• proteiny členovců chemie   farmakologie   metabolismus   MeSH
• sekvence aminokyselin MeSH
• slinné žlázy metabolismus   účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chymasy * MeSH
• inhibitory trypsinu MeSH
• proteiny členovců MeSH

BACKGROUND: Borrelia miyamotoi and Borrelia burgdorferi sensu lato (s.l.) are important zoonotic agents transmitted by Ixodes ricinus ticks, which are widely distributed across Central Europe. Understanding the spatial distribution of these pathogens' prevalence will help identify areas with increased infection risk and facilitate the implementation of effective preventive measures. METHODS: We analysed 12,955 I. ricinus ticks collected from 142 towns in the Czech Republic between 2016 and 2018. The ticks were pooled into 2591 groups of five and tested using duplex quantitative polymerase chain reaction (qPCR) for the presence of B. burgdorferi s.l. and B. miyamotoi. For each location, we estimated the overall prevalence of both agents using the EpiTools Epidemiological Calculator for pooled samples and calculated the minimum infection rate (MIR). To assess the potential risk of infection, we combined data on the abundance of nymphs and females with pathogen prevalence at each sampled site. Using a geographic information system (GIS), we mapped the MIR and infection risk of both Borrelia species across all 142 sampled locations and employed a geostatistical method (ordinary kriging) to predict MIR values and infection risk as continuous surfaces across the entire country. RESULTS: We detected B. miyamotoi in 110 localities and B. burgdorferi s.l. in all 142 localities. The estimated prevalence of B. miyamotoi and B. burgdorferi s.l. in the collected ticks was 2.1% (95% confidence interval [CI] 1.8-2.3) and 27.1% (95% CI 26.0-28.3), respectively. For B. miyamotoi, we identified previously unknown, geographically distinct hotspots of MIR up to 8.3%, with MIR slightly higher in females (2.3%) than in males (1.9%) and nymphs (1.8%), though the difference was not statistically significant. In contrast, B. burgdorferi s.l. exhibited ubiquitous presence, with consistently high prevalence nationwide, showing similar MIRs in females (16.2%) and males (16.1%), and slightly lower in nymphs (15.6%). The highest infection risk for B. miyamotoi was 12.4 infected vectors per hour in southeastern Moravia, while the highest risk for B. burgdorferi s.l. reached 78.6 infected vectors per hour in the Bohemian-Moravian Highlands. CONCLUSIONS: Borrelia miyamotoi is widespread, forming distinct high-prevalence areas in certain regions. Borrelia burgdorferi s.l. demonstrates consistently high prevalence across most of the country, except for a few localized areas such as southwestern Czechia. Both pathogens exhibit natural nidality, forming regions with elevated prevalence and infection risk. Long-term time-series data are needed to confirm the spatio-temporal stability of these hotspots.

• Klíčová slova
• Ixodes ricinus, Estimated prevalence, Geostatistical analysis, Minimum infection rate, Ordinary kriging, Relapsing fever, Risk maps,
• MeSH
• Borrelia burgdorferi komplex izolace a purifikace   genetika   MeSH
• Borrelia burgdorferi izolace a purifikace   genetika   MeSH
• Borrelia * izolace a purifikace   genetika   MeSH
• klíště * mikrobiologie   MeSH
• lidé MeSH
• lymeská nemoc epidemiologie   mikrobiologie   přenos   MeSH
• nymfa * mikrobiologie   MeSH
• prevalence MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH

AIM: To determine the occurrence of species of Babesia potentially pathogenic for humans in ticks and in the blood of dogs and deer in selected regions of the Czech Republic. To compare the prevalence of Babesia spp. in ticks with that of other tick-borne pathogens, such as Borrelia spp., Anaplasma spp., and Rickettsia spp. MATERIAL AND METHODS: Tick samples were individually homogenized. DNA was isolated from tick samples and animal blood. The detection of Babesia spp. was based on PCR of the 18S rRNA gene, and the identification to the species level was done by sequencing analysis of the PCR products. RESULTS: In 2014-2016, ticks and blood of dogs and deer collected in various areas of the Czech Republic were analyzed. In a set of 675 Ixodes ricinus ticks, the positivity rate for Babesia spp. varied from 0.0 to 3.3 %. The species Babesia venatorum, Babesia microti (both pathogenic for humans), and Babesia capreoli were identified in ticks by sequencing analysis. The prevalence of Babesia spp. in ticks compared to that of other pathogens such as Borrelia burgdorferi s. l. (29.3 %) or Anaplasma phagocytophilum (4.9 %) was lower and comparable to that of Rickettsia spp. (1.6 %). Co-infection with Borrelia burgdorferi s.l (B. venatorum - Borrelia garinii, Borrelia afzelii, and B. microti - B. afzelii) was found in a third of Babesia spp. positive ticks. Out of 109 dog blood samples, 3.7 % were positive for Babesia spp., specifically Babesia gibsoni and Babesia vulpes. Of 50 blood samples of wild deer from the natural ecosystem, the positivity rate reached 4.0 %. The species Babesia divergens, a major human pathogen, was identified. Out of 80 blood samples from farmed deer, 5.0 % were positive for the species Babesia odocoilei. Nucleotide sequences of the agents causing human babesiosis were deposited in the gene bank under accession numbers ON892053 (B. venatorum), ON892061 (B. microti), and ON892067 (B. divergens). CONCLUSIONS: Using PCR of the 18S rRNA gene and amplicon sequencing, three species of Babesia causing human babesiosis were detected in the Czech Republic: B. divergens, B. venatorum, and B. microti. Babesia spp. pathogenic for humans pose a potential risk especially in asplenic and immunocompromised patients. The detected co-infections with Borrelia spp. can be the cause of a complicated course of the disease.

• Klíčová slova
• Anaplasma spp., Babesia spp., Borrelia burgdorferi s. l., Czech Republic, Deer, PCR, Rickettsia spp., Sequence analysis, co-infection, dog, tick,
• MeSH
• Babesia * izolace a purifikace   genetika   klasifikace   MeSH
• babezióza epidemiologie   parazitologie   MeSH
• klíště * mikrobiologie   parazitologie   MeSH
• psi MeSH
• RNA ribozomální 18S genetika   MeSH
• vysoká zvěř * parazitologie   MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Názvy látek
• RNA ribozomální 18S MeSH

The vector competence of blood-feeding arthropods is influenced by the interaction between pathogens and the immune system of the vector. The Toll and IMD (immune deficiency) signaling pathways play a key role in the regulation of innate immunity in both the Drosophila model and blood-feeding insects. However, in ticks (chelicerates), immune determination for pathogen acquisition and transmission has not yet been fully explored. Here, we have mapped homologs of insect Toll and IMD pathways in the European tick Ixodes ricinus, an important vector of human and animal diseases. We show that most genes of the Toll pathway are well conserved, whereas the IMD pathway has been greatly reduced. We therefore investigated the functions of the individual components of the tick Toll pathway and found that, unlike in Drosophila, it was specifically activated by Gram-negative bacteria. The activation of pathway induced the expression of defensin (defIR), the first identified downstream effector gene of the tick Toll pathway. Borrelia, an atypical bacterium and causative agent of Lyme borreliosis, bypassed Toll-mediated recognition in I. ricinus and also resisted systemic effector molecules when the Toll pathway was activated by silencing its repressor cactus via RNA interference. Babesia, an apicomplexan parasite, also avoided Toll-mediated recognition. Strikingly, unlike Borrelia, the number of Babesia parasites reaching the salivary glands during tick infection was significantly reduced by knocking down cactus. The simultaneous silencing of cactus and dorsal resulted in greater infections and underscored the importance of tick immunity in regulating parasite infections in these important disease vectors.

• MeSH
• Babesia microti * imunologie   MeSH
• babezióza imunologie   parazitologie   MeSH
• klíště * parazitologie   imunologie   MeSH
• přirozená imunita MeSH
• signální transdukce * MeSH
• toll-like receptory * metabolismus   imunologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• toll-like receptory * MeSH

We detected 24 Encephalitozoon cuniculi positive Ixodes ricinus ticks of 284 collected in the Czech Republic. Since the route of transmission of microsporidia is not fully understood, the presence of microsporidia in ticks raises the question of whether they may be involved in the transmission of these pathogens.

• Klíčová slova
• Encephalitozoon cuniculi, Ixodes ricinus, PCR, qPCR, vector,
• MeSH
• Encephalitozoon cuniculi izolace a purifikace   genetika   MeSH
• encephalitozoonóza přenos   mikrobiologie   MeSH
• klíště * mikrobiologie   MeSH
• lidé MeSH
• mikrosporidióza přenos   MeSH
• nemoci přenášené klíšťaty přenos   mikrobiologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

Background: While the influence of landscape and microclimatic conditions on tick populations is well-documented, there remains a gap in more specific data regarding their relationship to rewilding efforts with large herbivore activity. Objective: This pilot study, spanning from 2019 to 2021, explores the effects of naturalistic grazing by large semi-wild ungulates on tick abundance in the Milovice Reserve, Czechia. Methods: Tick collection was observed using flagging techniques at two distinct sites of rewilding area: one grazed, actively utilized by animals involved in the rewilding project, and one ungrazed, left fallow in neighboring areas utilized only by wild animals. Transects, each measuring 150 m in length and 5 m in width (750 m2), were established at these two sampling locations from March to September between 2019 and 2021. To minimize potential bias resulting from tick movement, a 300 m buffer zone separated the two sites. Data analysis employed a generalized estimating equations (GEE) model with negative binomial regression. The study assessed potential variations in tick abundance between selected transects, considering factors such as plant cover seasonality, temperature, and humidity. Results: During the collection periods, we gathered 586 live ticks, with 20% found in grazed areas and 80% in ungrazed areas. Notably, tick abundance was significantly higher in ungrazed areas. Peaks in tick abundance occurred in both grazed and ungrazed areas during spring, particularly in April. However, tick numbers declined more rapidly in grazed areas. Microclimatic variables like temperature and humidity did not significantly impact tick abundance compared to landscape management and seasonal factors. Conclusion: Rewilding efforts, particularly natural grazing by large ungulates, influence tick abundance and distribution. This study provides empirical data on tick ecology in rewilded areas, highlighting the importance of landscape management and environmental factors in tick management and conservation. Trophic rewilding plays a crucial role in shaping ecosystems and tick population dynamics in transformed landscapes.

• Klíčová slova
• ecosystem, ecto-parasites, landscape management, large ungulates, seasonality, ticks,
• MeSH
• býložravci * MeSH
• ekosystém MeSH
• hustota populace MeSH
• klíště * fyziologie   MeSH
• pilotní projekty MeSH
• roční období MeSH
• zachování přírodních zdrojů MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

UNLABELLED: Lyme disease, caused by spirochetes in the Borrelia burgdorferi sensu lato clade within the Borrelia genus, is transmitted by Ixodes ticks and is currently the most prevalent and rapidly expanding tick-borne disease in Europe and North America. We report complete genome sequences of 47 isolates that encompass all established species in this clade while highlighting the diversity of the widespread human pathogenic species B. burgdorferi. A similar set of plasmids has been maintained throughout Borrelia divergence, indicating that they are a key adaptive feature of this genus. Phylogenetic reconstruction of all sequenced Borrelia genomes revealed the original divergence of Eurasian and North American lineages and subsequent dispersals that introduced B. garinii, B. bavariensis, B. lusitaniae, B. valaisiana, and B. afzelii from East Asia to Europe and B. burgdorferi and B. finlandensis from North America to Europe. Molecular phylogenies of the universally present core replicons (chromosome and cp26 and lp54 plasmids) are highly consistent, revealing a strong clonal structure. Nonetheless, numerous inconsistencies between the genome and gene phylogenies indicate species dispersal, genetic exchanges, and rapid sequence evolution at plasmid-borne loci, including key host-interacting lipoprotein genes. While localized recombination occurs uniformly on the main chromosome at a rate comparable to mutation, lipoprotein-encoding loci are recombination hotspots on the plasmids, suggesting adaptive maintenance of recombinant alleles at loci directly interacting with the host. We conclude that within- and between-species recombination facilitates adaptive sequence evolution of host-interacting lipoprotein loci and contributes to human virulence despite a genome-wide clonal structure of its natural populations. IMPORTANCE: Lyme disease (also called Lyme borreliosis in Europe), a condition caused by spirochete bacteria of the genus Borrelia, transmitted by hard-bodied Ixodes ticks, is currently the most prevalent and rapidly expanding tick-borne disease in the United States and Europe. Borrelia interspecies and intraspecies genome comparisons of Lyme disease-related bacteria are essential to reconstruct their evolutionary origins, track epidemiological spread, identify molecular mechanisms of human pathogenicity, and design molecular and ecological approaches to disease prevention, diagnosis, and treatment. These Lyme disease-associated bacteria harbor complex genomes that encode many genes that do not have homologs in other organisms and are distributed across multiple linear and circular plasmids. The functional significance of most of the plasmid-borne genes and the multipartite genome organization itself remains unknown. Here we sequenced, assembled, and analyzed whole genomes of 47 Borrelia isolates from around the world, including multiple isolates of the human pathogenic species. Our analysis elucidates the evolutionary origins, historical migration, and sources of genomic variability of these clinically important pathogens. We have developed web-based software tools (BorreliaBase.org) to facilitate dissemination and continued comparative analysis of Borrelia genomes to identify determinants of human pathogenicity.

• Klíčová slova
• Borrelia burgdorferi, Lyme disease, evolution, genome diversification, plasmids, recombination,
• MeSH
• Borrelia burgdorferi komplex genetika   klasifikace   MeSH
• Borrelia burgdorferi genetika   klasifikace   MeSH
• Borrelia genetika   klasifikace   MeSH
• fylogeneze * MeSH
• genetická variace MeSH
• genom bakteriální * MeSH
• interakce mikroorganismu a hostitele genetika   MeSH
• klíště mikrobiologie   MeSH
• lidé MeSH
• lipoproteiny * genetika   MeSH
• lymeská nemoc * mikrobiologie   přenos   MeSH
• molekulární evoluce MeSH
• plazmidy genetika   MeSH
• rekombinace genetická * MeSH
• sekvenování celého genomu MeSH
• selekce (genetika) * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH
• Severní Amerika MeSH
• Názvy látek
• lipoproteiny * MeSH

OBJECTIVES: The purpose of the current study was to analyse the risks of Lyme borreliosis (LB) among 1,070 forestry workers, the influence of responsible behaviour (use of repellents, skin self-inspection) on Borrelia screening result status, and the occurrence of immediate and mid-term symptoms after tick bites and LB positive serological screening test. METHODS: The questionnaire was conducted as well as blood tests for LB disease by one-stage serological screening procedure using ELISA for specific B. burgdorferi IgM and IgG antibodies (EuroImmun AG company, Germany). RESULTS: While 39.6% of foresters were LB positive among bitten foresters, as many as 27.0% were LB positive among those, who did not recall any tick attacks at all. Individuals with known history of tick bites had significantly higher odds (1.770×) of being LB positive (p < 0.05), while the use of repellents or skin self-inspection after visiting woods had no influence on LB results. The odds of skin discolouration after tick bites was significantly lower (0.682×) in case of LB positive test compared to LB negative test (p < 0.05), which can be explained by the fact that foresters could be unaware about erythema migrans appearance and timing, considering tick bite and developed later rash as completely separate events. Moreover, 69.1% of the bitten foresters with LB positive result developed no secondary symptoms (excluding those related to the skin), and the most frequent clinical symptoms were arthralgia (24.9%), followed by myalgia (7.6%), headache (5.7%), and damage to facial nerve (2.7%), which are non-specific and can be present in other illnesses. CONCLUSION: Therefore, the recommendations proposed would be the regular laboratory testing for LB of sensitive and at-risk population, who visits endemic woody areas, irrespective of all other factors involved.

• Klíčová slova
• Lyme borreliosis, foresters, risk,
• MeSH
• Borrelia burgdorferi imunologie   izolace a purifikace   MeSH
• dospělí MeSH
• ELISA MeSH
• klíště * MeSH
• kousnutí klíštětem * MeSH
• lesnictví MeSH
• lidé středního věku MeSH
• lidé MeSH
• lymeská nemoc * epidemiologie   MeSH
• průzkumy a dotazníky MeSH
• senioři MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Německo epidemiologie   MeSH