Persulcatus Ticks Research Articles

Targeting Yezo Virus Structural Proteins for Multi-Epitope Vaccine Design Using Immunoinformatics Approach.

A novel tick-borne orthonairovirus called the Yezo virus (YEZV), primarily transmitted by the Ixodes persulcatus tick, has been recently discovered and poses significant threats to human health. The YEZV is considered endemic in Japan and China. Clinical symptoms associated with this virus include thrombocytopenia, fatigue, headache, leukopenia, fever, depression, and neurological complications ranging from mild febrile illness to severe outcomes like meningitis and encephalitis. At present, there is no treatment or vaccine readily accessible for this pathogenic virus. Therefore, this research employed an immunoinformatics approach to pinpoint potential vaccine targets within the YEZV through an extensive examination of its structural proteins. Three structural proteins were chosen using specific criteria to pinpoint T-cell and B-cell epitopes, which were subsequently validated through interferon-gamma induction. Six overlapping epitopes for cytotoxic T-lymphocytes (CTL), helper T-lymphocytes (HTL), and linear B-lymphocytes (LBL) were selected to construct a multi-epitope vaccine, achieving a 92.29% coverage of the global population. These epitopes were then fused with the 50S ribosomal protein L7/L12 adjuvant to improve protection against international strains. The three-dimensional structure of the designed vaccine construct underwent an extensive evaluation through structural analysis. Following molecular docking studies, the YEZV vaccine construct emerged as a candidate for further investigation, showing the lowest binding energy (-78.7 kcal/mol) along with favorable physiochemical and immunological properties. Immune simulation and molecular dynamics studies demonstrated its stability and potential to induce a strong immune response within the host cells. This comprehensive analysis indicates that the designed vaccine construct could offer protection against the YEZV. It is crucial to conduct additional in vitro and in vivo experiments to verify its safety and effectiveness.

First Genomic Evidence of California Hare Coltivirus from Natural Populations of Ixodes persulcatus Ticks in Northeast China.

Background: California hare coltivirus (CHCV) was isolated in California in 1976 from a hare. Despite its long history, it remained unclear whether CHCV was exclusively distributed in California with limited host ranges. Main body: By next-generation sequencing (NGS), we obtained a complete sequence of CHCV from Ixodes persulcatus collected in 2019 in northeast China. An expanded epidemiological investigation was subsequently performed on ticks belonging to four species (Ix. persulcatus, Haemaphysalis concinna, Devmacentor silvarum, Haemaphysalis longicornis) collected in northeastern China by applying CHCV-specific RT-PCR and sequencing. CHCV RNA-positive results were found in 1.56% of the tick samples. Positive ticks were obtained in three of four sampled locations, with the highest rate observed in Inner Mongolia (2.69%), followed by Heilongjiang (1.94%) and Jilin provinces (0.55%). All positive results were derived from Ix. persulcatus ticks (2.33%), while no positive detection was found in the other tick species, even at the same location. Sequence analysis revealed that the current CHCV showed a high genetic identity (>80% amino acid identity) with the previously reported CHCV in all segments except segment seven (64.59% amino acid identity). Phylogenetic analysis based on RNA-dependent RNA polymerase (RdRp) amino acid sequences demonstrated that both the current and previously reported CHCV strains were grouped phylogenetically into the genus Coltivirus. Both CHCV strains formed a distinct clade, clustering with three human pathogenic coltiviruses (Colorado tick fever virus, Salmon River virus, and Eyach virus), and were distant from the other coltiviruses. Conclusions: We report the identification and characterization of CHCV for the first time in Ix. persulcatus ticks, expanding the currently known geographic scope, host, and genetic heterogeneity in CHCV.

TBE In Mongolia

In Mongolia, TBEV was first isolated (Kraminskii V.A) from marmot liver in Dornod province in 1979, while the Ixodes persulcatus tick was identified in 1987 by M. Dash.1,2 I. persulcatus is a taiga tick distributed in coniferous forests consisting mostly of pines, spruces and larches.3 Much of northern Mongolia is covered in coniferous forest, and the southern edge of the Siberian taiga is located along the Khangai and Khentii mountains.

Characteristics of tickborne infections in the underexplored areas of the Trans-Baikal Territory

Background. Infections transmitted to humans by the bites of ixodid ticks remain an urgent public health problem. In this work we explored the natural foci of tickborne infections located in the valley of the Chikoy River, which is a part of the buffer zone of the Baikal natural territory.The aim. To characterize the modern diversity and prevalence of tick-borne pathogens in the ecosystems of the valley of the Chikoy River (Trans-Baikal Territory, Russian Federation).Materials and methods. Thirteen sampling sites were located in typical biotopes throughout the Chikoy valley. In total 48 adult Ixodes persulcatus ticks, 1 female Haemaphysalis concinna tick and 38 specimens of small mammals were studied. All samples were tested for infection with seven tick-borne pathogens using multiplex real-time PCR.Results. No pathogens were detected in the H. concinna specimen. No R. sibirica and R. heilongjiangensis were detected both in ticks and in rodents. Among I. persulcatus, tick-borne encephalitis virus (TBEV), and the prevalence of Borrelia burgdorferi s. l. comprised 39.5 %, A. phagocytophilum – 16.7 %, B. miyamotoi – 8.3 % and Ehrlichia sp. – 2.1 %. Among infected ticks 6.2 % were co-infected with B. burgdorferi s. l. and A. phagocytophilum. Four rodent hosts of ticks and infections were identified: Myodes rufocanus (44.7 %), Apodemus peninsulae (39 %), Microtus oeconomus (13.2 %) and M. rutilus (2.6 %). Mean prevalence of B. burgdorferi s. l. in rodents comprised 39.5 %, B. miyamotoi – 28.9 %, Ehrlichia sp. – 21.1 % and A. phagocytophilum – 18.4 %. TBEV was detected in 5.3 % of rodents.Conclusion. At least five tick-borne pathogens circulate in the Chikoi River valley, i. e. TBEV, B. burgdorferi sensu lato, A. phagocytophilum, B. miyamotoi and Ehrlichia sp. The wide spread of I. persulcatus and abundance of competent rodent hosts of infections and ticks indicates that natural foci of tick-borne diseases are widely distributed in the Chikoi River valley.

Comparative analysis of Presence-Absence gene Variations in five hard tick species: impact and functional considerations

Tick species are vectors of harmful human and animal diseases, and their expansion is raising concerns under the global environmental changes’ scenario. Ticks host and transmit bacteria, protozoa and viruses, making the understanding of host-pathogen molecular pathways critical to development of effective disease control strategies. Despite the considerable sizes and repeat contents of tick genomes, individual tick genomics is perhaps the most effective approach to reveal genotypic traits of interest. Presence-Absence gene Variations (PAVs) can contribute to individual differences within species, with dispensable genes carried by subsets of individuals possibly underpinning functional significance at individual or population-levels. We exploited 350 resequencing datasets of Dermacentor silvarum, Haemaphysalis longicornis, Ixodes persulcatus, Rhipicephalus microplus and Rhipicephalus sanguineus hard tick specimens to reveal the extension of PAV and the conservation of dispensable genes among individuals and, comparatively, between species. Overall, we traced 550–3,346 dispensable genes per species and were able to reconstruct 5.3–7 Mb of genomic regions not included in the respective reference genomes, as part of the tick pangenomes. Both dispensable genes and de novo predicted genes indicated that PAVs preferentially impacted mobile genetic elements in these tick species.

Development Features of Ixodes ricinus × I. persulcatus Hybrids under Laboratory Conditions.

Widely distributed Ixodes ricinus and Ixodes persulcatus ticks transmit many pathogens of both medical and veterinary significance. The ranges of these tick species overlap and form large sympatric areas in the East European Plain and Baltic countries. It has previously been shown that crossing I. ricinus and I. persulcatus is possible, resulting in the appearance of sterile hybrids. In the present study, we analyzed the features of this hybrid's life cycle under laboratory conditions. For this purpose, virgin females of I. ricinus and I. persulcatus ticks were obtained in the laboratory, and hybrid generations of ticks were bred from the reciprocal crossings of these two tick species. According to our data, mating the females of I. ricinus and I. persulcatus with the males of another species leads to a decrease in the engorgement success of the females, a decrease in the number of hatched larvae, and the appearance of a hybrid generation in which both females and males are sterile. Under laboratory conditions at a constant room temperature and under natural daylight, the morphogenetic diapause of the engorged I. persulcatus larvae began in September. For I. persulcatus nymphs, it occurred earlier than for I. ricinus, in October and November, respectively. The hybrids generally repeated the features of the life cycle of the mother species.

Study of Viral Coinfection of the Ixodes persulcatus Ticks Feeding on Humans in a Natural Focus of the South of the Far East.

The phenomenon of pathogen co-infection detected in a half-fed Ixodes persulcatus tick taken from a human in the south of the Far East was studied. Research was carried out on PEK, Vero, and Vero-E6 cell lines, outbred mice, and chicken embryos using ELISA, PCR, IMFA, plaque formation, and electron microscopy. The tick contained an antigen and a genetic marker of the tick-borne encephalitis virus (TBEV). The patient had post-vaccination antibodies in a titer of 1:200, as a result of which, obviously, an antibody-dependent elimination of TBEV occurred. The tick-borne co-isolate also contained an unknown pathogen (Kiparis-144 virus), which, in our opinion, was a trigger for the activation of chronic infection in suckling white mice. In the laboratory co-isolate, ectromelia virus was present, as evidenced by paw edema during the intradermal infection of mice, characteristic rashes on the chorioallantoic envelope of chicken embryos, and typical plaques on Vero-E6. The Kiparis-144 virus was not pathogenic for white mice and chicken embryos, but it successfully multiplied in the PEK, Vero, and Vero-E6 lines. Viral co-infection was confirmed by electron microscopy. Passaging on mice contributed to an increase in the virulence of the co-isolate, whose titer increased by 10,000 times by the fifth passage, which poses an epidemiological danger.

Applying next generation sequencing to detect tick-pathogens in Dermacentor nuttalli, Ixodes persulcatus, and Hyalomma asiaticum collected from Mongolia

Ticks and tick-borne diseases represent major threats to the public health of the Mongolian population, of which an estimated 26% live a traditional nomadic pastoralist lifestyle that puts them at increased risk for exposure. Ticks were collected by dragging and removal from livestock in Khentii, Selenge, Tuv, and Umnugovi aimags (provinces) during March-May 2020. Using next-generation sequencing (NGS) with confirmatory PCR and DNA sequencing, we sought to characterize the microbial species present in Dermacentor nuttalli (n = 98), Hyalomma asiaticum (n = 38), and Ixodes persulcatus (n = 72) tick pools. Rickettsia spp. were detected in 90.4% of tick pools, with Khentii, Selenge, and Tuv tick pools all having 100% pool positivity. Coxiella spp. were detected at an overall pool positivity rate of 60%, while Francisella spp. were detected in 20% of pools and Borrelia spp. detected in 13% of pools. Additional confirmatory testing for Rickettsia-positive pools demonstrated Rickettsia raoultii (n = 105), Candidatus Rickettsia tarasevichiae (n = 65) and R. slovaca/R. sibirica (n = 2), as well as the first report of Candidatus Rickettsia jingxinensis (n = 1) in Mongolia. For Coxiella spp. reads, most samples were identified as a Coxiella endosymbiont (n = 117), although Coxiella burnetii was detected in eight pools collected in Umnugovi. Borrelia species that were identified include Borrelia burgdorferi sensu lato (n = 3), B. garinii (n = 2), B. miyamotoi (n = 16), and B. afzelii (n = 3). All Francisella spp. reads were identified as Francisella endosymbiont species. Our findings emphasize the utility of NGS to provide baseline data across multiple tick-borne pathogen groups, which in turn can be used to inform health policy, determine regions for expanded surveillance, and guide risk mitigation strategies.

TBE in Mongolia

In Mongolia, TBEV was first isolated (Kraminskii V.A) from marmot liver in Dornod province in 1979, while the Ixodes persulcatus tick was identified in 1987 by M. Dash. I. persulcatus is a taiga tick distributed in coniferous forests consisting mostly of pines, spruces and larches. Much of northern Mongolia is covered in coniferous forest, and the southern edge of the Siberian taiga is located along the Khangai and Khentii mountains.

Candidatus Lariskella arthopodarum endosymbiont is the main factor differentiating the microbiome communities of female and male Borrelia-positive Ixodes persulcatus ticks

Ixodes persulcatus, a hard-bodied tick species primarily found in Asia and Eastern Europe, is a vector of pathogens to human and livestock hosts. Little research has been done on the microbiome of this species, especially using individual non-pooled samples and comparing different geographical locations. Here, we use 16S rRNA amplicon sequencing to determine the individual microbial composition of 85 Borrelia-positive I. persulcatus from the Japanese islands of Hokkaido and Honshu. The resulting data (164 unique OTUs) were further analyzed to compare the makeup and diversity of the microbiome by sex and location, as well as to determine the presence of human pathogens. We found that, while location had little influence, the diversity of I. persulcatus microbiome was predominantly dependent on sex. Males were seen to have higher microbiome diversity than females, likely due to the high presence of endosymbiotic Candidatus Lariskella arthropodarum within the female microbial communities. Furthermore, high read counts for five genera containing potentially human pathogenic species were detected among both male and female microbiomes: Ehrlichia, Borrelia, Rickettsia, Candidatus Neoehrlichia and Burkholderia and co-infections between different pathogens were frequent. We conclude that the microbiome of I. persulcatus depends mainly on sex and not geographical location and that the major difference between sexes is due to the high abundance of Ca. L. arthropodarum in females. We also stress the importance of this tick species as a vector of potential human pathogens frequently found in co-infections.

Dairy milk from cow and goat as a sentinel for tick-borne encephalitis virus surveillance.

Tick-borne encephalitis (TBE) is one of the most severe human tick-borne diseases in Europe. It is caused by the tick-borne encephalitis virus (TBEV), which is transmitted to humans mainly via bites of Ixodes ricinus or I. persulcatus ticks. The geographical distribution and abundance of I. ricinus is expanding in Sweden as has the number of reported human TBE cases. In addition to tick bites, alimentary TBEV infection has also been reported after consumption of unpasteurized dairy products. So far, no alimentary TBEV infection has been reported in Sweden, but knowledge about its prevalence in Swedish ruminants is scarce. In the present study, a total of 122 bulk tank milk samples and 304 individual milk samples (including 8 colostrum samples) were collected from dairy farms (n=102) in Sweden. All samples were analysed for the presence of TBEV antibodies by ELISA test and immunoblotting. Participating farmers received a questionnaire about milk production, pasteurization, tick prophylaxis used on animals, tick-borne diseases, and TBE vaccination status. We detected specific anti-TBEV antibodies, i.e., either positive (>126 Vienna Units per ml, VIEU/ml) or borderline (63-126 VIEU/ml) in bulk tank milk from 20 of the 102 farms. Individual milk samples (including colostrum samples) from these 20 farms were therefore collected for further analysis. Our results revealed important information for detection of emerging TBE risk areas. Factors such as consumption of unpasteurized milk, limited use of tick prophylaxis on animals and a moderate coverage of human TBE vaccination, may be risk factors for alimentary TBEV infection in Sweden.

Genotyping of tick-borne pathogens and determination of human attacking tick species in Novosibirsk and its suburbs

The south of Western Siberia traditionally belongs to the regions with unfavorable epidemiological situation for tick-transmitted infections. In Novosibirsk and its suburbs, approximately 20 thousand people annually seek for medical care after tick bites. The purpose of this work was to determine human-attacking tick species composition in the territory of Novosibirsk and its suburbs by identifying nucleotide sequence of tick mitochondrial gene cytochrome oxidase COI fragment during the 2018 spring-summer season, determination of infections of individual ticks with viral and bacterial tick-borne infections, followed by genotyping identified pathogens by PCR methods, by determining nucleotide sequences and phylogenetic analysis. It is established that ticks of five species attack the humans: Ixodes persulcatus, Ixodes pavlovskyi, Dermacentor reticulatus, Dermacentor marginatus, Dermacentor nuttali in the Novosibirsk metropolis. The majority of tick attacks on humans are associated with I. pavlovskyi (43.6%) and D. reticulatus (41.2%) ticks. The genetic material of the tick-borne encephalitis virus was detected in 3.6%, borrelia 13.8% and Rickettsia 23.1% individual ticks collected from humans. Genotyping of the tick-borne encephalitis virus (TBEV) in the collected ticks showed the presence of TBEV Siberian and Far Eastern genotype in 83% and 17% cases, respectively. The Kemerovo virus could not be detected. Genetic material from Borrelia spp. and Rickettsia spp. has been detected in all five tick species attacking the local human population. The bulk of the identified Borrelia spp. isolates were genotyped as Borrelia garinii (86%) and 13% of the isolates as Borrelia afzelii species. The genetic material of Borrelia miyamotoi was found in one individual tick. Ticks of the genus Dermacentor have been found to be infected by Rickettsia raoultii, and ticks of the genus Ixodes were largely infected with Rickettsia tarasevichiae, and I. persulcatus tick was infected by Rickettsia helvetica in a single case. Thus, the human population of Novosibirsk and its suburbs is attacked by five species of ixodid ticks dominated by I. pavlovskyi and D. reticulatus ticks. The genetic material of the following tick-borne pathogens was found: Siberian and Far Eastern TBEV genotype, B. garinii, B. afzelii, B. miyamotoi, R. raoulti, R. tarasevichiae and R. helvetica in the individual ticks collected from humans.

Differentiation of Laboratory-Obtained Ixodes ricinus × Ixodes persulcatus Hybrid Ticks: Selection of Suitable Genes.

Ixodes ricinus and Ixodes persulcatus ticks are the main vectors of tick-borne encephalitis virus and some bacterial pathogens. The regions where these tick species live overlap, forming large sympatric areas. It has previously been shown that these tick species have no morphological barrier, and interspecies crossing is possible with the appearance of sterile hybrids. It has also been shown that hybrid larvae and nymphs can be differentiated using discriminant functions based on a set of morphological features. However, such an approach is laborious and rather ineffective with adult ticks, making a molecular approach necessary. In the current work, we tested the ability of different systems to differentiate laboratory-obtained hybrid ticks. Our data suggest that commonly used primer sets that target rRNA are unsuitable for hybrid tick determination, likely due to the rRNA region being linked with the X chromosome in I. ricinus and I. persulcatus ticks. We tested several primer sets targeting different non rRNA genes to assess their ability to determine hybrids. The best primer set, Toll_R, targeting the putative Toll gene, showed little to no bias when used for DNA amplification from hybrid ticks. Thus, Toll gene can be further used for hybrid detection.

Состояние популяций и инфицированность переносчиков возбудителей клещевых трансмиссивных инфекций в городской среде и пригородной зоне на примере г. Хабаровска

Annual submissions regarding ixodic ticks suction are registered in Khabarovsk. The research presents data of entomological observations of ixodic ticks population as well as their infection rate with tick-borne infections in the Khabarovsk city and its rural zone. Circulation of six epidemiologically significant species of Ixodidae family ticks that belong to three genus were detected in natural and anthropogenically transformed biocenoses of the Khabarovsk city and its rural area: Ixodes (I. persulcatus, I. pavlovskyi), Haemaphysalis (H. japonica, H. concinna) and Dermacentor (D. silvarum, D. reticulatus). Study revealed that I. persulcatus ticks were infected as well as greater number of tick-borne infections pathogens were isolated in this tick species, which specifies their high epidemiological significance. The fact of discovery of new types of carriers necessitates studies for evaluation of their infection rate and clarification of their role as tick-borne infection vectors. Keywords: ixodic ticks, infection rate, tick-borne infections, rural zone, urban environment.

Evaluation of Vector Competence of Ixodes Ticks for Kemerovo Virus

Tick-borne viruses are responsible for various symptoms in humans and animals, ranging from simple fever to neurological disorders or haemorrhagic fevers. The Kemerovo virus (KEMV) is a tick-borne orbivirus, and it has been suspected to be responsible for human encephalitis cases in Russia and central Europe. It has been isolated from Ixodes persulcatus and Ixodes ricinus ticks. In a previous study, we assessed the vector competence of I. ricinus larvae from Slovakia for KEMV, using an artificial feeding system. In the current study, we used the same system to infect different tick population/species, including I. ricinus larvae from France and nymphs from Slovakia, and I. persulcatus larvae from Russia. We successfully confirmed the first two criteria of vector competence, namely, virus acquisition and trans-stadial transmission, for both tick species that we tested. The estimated infection rates of engorged and moulted ticks suggest specificities between viral strains and tick species/developmental stages.

Virome and Blood Meal-Associated Host Responses in Ixodes persulcatus Naturally Fed on Patients.

The long-lasting co-evolution of ticks with pathogens results in mutual adaptation. Blood-feeding is one of the critical physiological behaviors that have been associated with the tick microbiome; however, most knowledge was gained through the study of laboratory-reared ticks. Here we detached Ixodes persulcatus ticks at different stages of blood-feeding from human patients and performed high-throughput transcriptomic analysis on them to identify their virome and genes differentially expressed between flat and fully fed ticks. We also traced bloodmeal sources of those ticks and identified bats and three other potential mammalian hosts, highlighting the public health significance. We found Jingmen tick virus and 13 putative new viruses belonging to 11 viral families, three of which even exhibited high genetic divergence from viruses previously reported in the same tick species from the same geographic region. Furthermore, differential expression analysis suggested a downregulation of antioxidant genes in the fully fed I. persulcatus ticks, which might be related to bloodmeal-related redox homeostasis. Our work highlights the significance of active surveillance of tick viromes and suggests a role of reactive oxygen species (ROS) in modulating changes in the microbiome during blood-feeding.

Food-Borne Transmission of Tick-Borne Encephalitis Virus-Spread, Consequences, and Prophylaxis.

Tick-borne encephalitis (TBE) is the most common viral neurological disease in Eurasia. It is usually transmitted via tick bites but can also occur through ingestion of TBEV-infected milk and dairy products. The present paper summarises the knowledge of the food-borne TBEV transmission and presents methods for the prevention of its spread. The incidence of milk-borne TBE outbreaks is recorded in central, eastern, and north-eastern Europe, where Ixodes ricinus, Ixodes persulcatus, and/or Dermacentor reticulatus ticks, i.e., the main vectors of TBEV, occur abundantly. The growing occurrence range and population size of these ticks increases the risk of infection of dairy animals, i.e., goats, sheep, and cows, with viruses transmitted by these ticks. Consumers of unpasteurised milk and dairy products purchased from local farms located in TBE endemic areas are the most vulnerable to alimentary TBEV infections. Familial infections with these viruses are frequently recorded, mainly in children. Food-transmitted TBE can be monophasic or biphasic, and some of its neurological and psychiatric symptoms may persist in patients for a long time. Alimentary TBEV infections can be effectively prevented by consumption of pasteurised milk and the use of TBEV vaccines. It is recommended that milk and dairy products should be checked for the presence of TBE viruses prior to distribution. Protection of dairy animals against tick attacks and education of humans regarding the epidemiology and prophylaxis of TBE are equally important.

Modification of isothermal test for detecting DNA of pathogens of tick-borne borreliosis.

Early diagnosis of tick-borne borreliosis determines the indications for etiotropic therapy, and the detection of borrelia in a tick that has bitten you serves as the basis for antibiotic prophylaxis. To determine the causative agent of borreliosis, PCR methods are most widely used, which requires special conditions for organizing the work of laboratories and the use of expensive equipment. In addition, the procedure for isolating bacterial DNA and subsequent amplification takes several hours of working time. At the same time, methods for detecting borrelia in the isothermal LAMP-reaction are described, which makes it possible to significantly speed up the diagnosis, does not require complex equipment and highly qualified personnel. It is also known that LAMP in some cases allows analysis without prior extraction of nucleic acids. The purpose was a development of a modified test for isothermal detection of DNA of borreliosis pathogens for an accelerated result and the possibility of excluding the stage of nucleic acid extraction. We used 40 samples of Borrelia DNA and 11 Ixodes persulcatus ticks. To shorten the detection time for Borrelia, the previously described LAMP method was modified by the introduction of additional loop primers. The copy number of the positive DNA sample of the borrelia plasmid was estimated using digital PCR. The results of the LAMP reaction were compared with those of the commercial PRC-RT test. The additional use of loop primers approximately halved the detection time for Borrelia DNA without affecting the comparative diagnostic efficiency. The analytical sensitivity limit of the modified LAMP method was 4 copies/μl or 21 molecules of the plasmid standard added to the reaction. In comparative testing with RT-PCR, the sensitivity of the LAMP method is 90%, and the specificity is 100%. The possibility of detecting borrelia in ticks without the stage of DNA extraction has been demonstrated for the first time. A modified isothermal method for the detection of pathogens of tick-borne borreliosis has been developed, which allows analysis within 20-30 minutes, including in ticks without preliminary DNA extraction.

Tick-borne encephalitis

Tick-borne encephalitis (TBE) is the most prevalent viral tick-borne zoonosis in Europe and Northern Asia. TBE is prevalent over a so-called “TBE belt,” which extends across Eurasia from Central Europe to the Pacific.The disease is caused by the TBEV, about 20 years ago, the TBEV was divided into three main subtypes: European, Siberian, and Far-Eastern.Major virus vectors are I. ricinus and I. persulcatus ticks. Nevertheless in 2019, H. marginatum was discovered for the first time in Germany, which can transmit a large number of diseases.

Surveillance of Borrelia miyamotoi-carrying ticks and genomic analysis of isolates in Inner Mongolia, China

BackgroundBorrelia miyamotoi is a newly described relapsing fever spirochete transmitted by ixodid tick species. Little is known about the prevalence of B. miyamotoi infections in humans and ticks in Inner Mongolia, China. Therefore, we investigated the prevalence of B. miyamotoi in Ixodes persulcatus ticks, and we aimed to isolateB. miyamotoi from I. persulcatus from four regions of Greater Khingan, Inner Mongolia, China.MethodsFrom May to June each year during the period 2016–2019, host-seeking adult I. persulcatus ticks were collected from vegetation. Genomic DNA was prepared from half of each tick body for PCR template, and the remaining half was used to cultivate B. miyamotoi in BSK-M medium. We employed quantitative real-time PCR (qPCR) to detect Borrelia DNA in the ticks and to calculate the prevalence of B. miyamotoi and infections with other borreliae. For characterization of the isolated B. miyamotoi, we performed draft genome sequencing and multilocus sequencing analysis (MLSA).ResultsA total of 2656 adult I. persulcatus ticks were collected. The overall prevalence of relapsing fever (RF) borreliae in ticks was 5.0% (134/2656) and that of Lyme disease (LD) borreliae was 43.8% (1164/2656). Co-infection with RF and LD borreliae was observed in 63 ticks (2.4%). Ticks that were positive for RF borreliae by qPCR were subjected to glycerophosphodiester diester phosphodiesterase gene (glpQ) PCR amplification and sequencing, through which we identified the RF borrelia specimens as B. miyamotoi. Furthermore, the B. miyamotoi strain Hetao-1 was isolated from I. persulcatus, and a draft genome sequence was obtained from the isolate. Sequencing determined the strain Hetao-1 genome to be approximately 906.1 kbp in length (28.9% average GC content), and MLSA identified the strain as ST633, which has previously been reported in Japan and Mongolia.ConclusionWe detected B. miyamotoi from I. persulcatus ticks collected in Inner Mongolia, and successfully isolated a B. miyamotoi strain. To our knowledge, this is the first study to culture a B. miyamotoi isolate from China. The data on the prevalence of B. miyamotoi and other borreliae in I. persulcatus ticks will be fundamental for future epidemiological studies of B. miyamotoi disease in Inner Mongolia.