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Background. Tick-borne bacterial and protozoal pathogens pose a significant public health problem. The aim of this study was to detect and genotype Borrelia, Rickettsia and Anaplasma in Ixodes ricinus and Dermacentor reticulatus ticks collected in the Kaliningrad region in 2021–2022. Materials and methods. The study included 862 I. ricinus and 803 D. reticulatus ticks (1665 in total) collected in 33 biotopes of the Kaliningrad region. Detection of the DNA of tick-borne pathogens was carried out in individual ticks by PCR using a set of specific primers, followed by sequencing and phylogenetic analysis. Results. The level of infection of I. ricinus ticks with Borrelia was 15.5%, and genotyping by the p66 gene sequence showed the presence of genetic material from four species: B. afzelii, B. garinii, B. valaisiana, and B. lusitaniae. In D. reticulatus ticks, no Borrelia genetic material was detected. The Rickettsia DNA has been found in both tick species. Moreover, the infection rate of I. ricinus ticks was 2.6%, and D. reticulatus — 21.2%. R. helvetica were found in I. ricinus ticks, and R. raoultii in meadow ticks when genotyping by gltA gene. Genetic markers of Anaplasma phagocytophilum have been found in I. ricinus and D. reticulatus ticks. Cases of co-infection of an individual tick have also been identified. Conclusion. Six different species of tick-borne pathogens were found in the I. ricinus and D. reticulatus ticks collected in the Kaliningrad region and R. helvetica, R. raoultii and A. phagocytophilum were identified for the first time.

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.

The aim of the study was to analyze the genetic markers of Lyme disease pathogens, which can be used to specifically indicate maximum number of their strains and isolates. Materials and methods. The nucleotide sequences of various genes of Borrelia garinii, B. afzelii, B. burgdorferi were downloaded from the NCBI database (National Center for Biological Informatization). The occurrence of the analyzed nucleotide sequences in the genetic code of various organisms was determined in the nBLAST software utility. For the design of primers and probes, the Vector NTI 9.1.0 program (“Invitrogen Corporation”, Carlsbad, USA) was used. DNA was isolated using the MAGNO-sorb kit, version 100-200 (“AmpliSens”, Moscow, Russia), according to the manufacturer’s instructions. Primers and probes were synthesized at “Evrogen” company (Moscow, Russia). For PCR, reagents manufactured by “Synthol” company (Moscow, Russia) were applied.Results and discussion. In order to perform the reliable indication of pathogenic Borrelia, specific loci (genes) of B. garinii, B. afzelii, B. burgdorferi, which were significantly different from the genetic code of other representatives of the genus Borrelia and from the DNA of other organisms, have been determined by molecular-genetic methods. As a result of a preliminary determination of the analytical significance of the studied loci, the following genes and loci were selected for further work: pepX, clpA, ospA, p83/100, ospC and flaB, of which the flaB and ospA genes were selected for practical indication of pathogenic Borrelia DNA. The genetic markers of B. burgdorferi and B. afzelii are displayed during amplification of the flaB gene, while B. garinii and B. afzelii occur when the ospA gene is used as a genetic marker.

Relevance. Tick-borne relapsing fevers caused by Borrelia species pathogenic for humans are not well understood. Aim of this review is to assess the genetic diversity of Borrelia with special attention to the relapsing fever group and phylogenetically related species carried by ticks. The review also provides up-to-date information on the main vectors and their geographic distribution, reservoirs of borrelia – pathogens, and potential pathogens of tick-borne recurrent fevers. Conclusions. New types of Borrelia, including a candidate, of relapsing fever clade and related phylogenetic lines/groups, which are carried not only by argasid, but also by solid-body ixodids ticks, deserve further study. The preservation of the epidemic potential of tick-borne relapsing fever can be facilitated by climatic changes, and poorly studied adaptation mechanisms of Borrelia to the range of vectors.

Introduction: Lyme disease is the most common disease transmitted by ticks. In Poland, over 20,000 cases of this disease were diagnosed in 2019. The first vaccine approved to prevent this condition was Lymerix. Currently, we do not have any preparation registered for this purpose. Data from Phase 2 trials of VLA15 show strong immunogenicity in both adults and children, with an acceptable safety and tolerability profile in both study populations Aim: The purpose of this paper is to present the current state of the art in research into the VLA15 vaccine. Results: Phase 3 of the VALOR study has started. Ultimately, about 6,000 participants aged 5 and older are to take part in it. The experiment is conducted in a dozen or so sites located in areas where Lyme disease is highly endemic. Participants will receive three doses of VLA15 180 µg or a placebo in saline as the first series of vaccinations, followed by one booster dose of VLA15 or placebo in 0.9% NaCl (1: 1 ratio). Conclusion: Phase 2 studies on VLA15 showed promising results. Phase 3 of the research is ongoing. Key words: VLA15, Lyme disease, Borrelia

Tick-borne bacterial and viral infections are widespread in middle latitudes of the Northern hemisphere. Natural foci of such infections coincide with geographic areas inhabited by ixodid ticks. Ixodid tick-borne borreliosis is a pressing issue for some territories of Russia, especially for the North-Western Federal District and St. Petersburg megalopolis as well as adjacent areas of the Leningrad District, where people may become infected after tick bite in recreational zones in suburban park areas. Currently, very few publications regarding prevalence of tick-borne pathogens in St. Petersburg area are available. In our study, questing ticks flagged in park zone (northern coast of Finnish Gulf, Kurortny District) were examined with PCR for carriage of pathogenic B. burgdorferi sensu lato complex. In addition, samples positive for Borrelia DNA signal were further genotyped with species-specific primers against rpoBgene fragment. It was found that Ixodes persulcatus dominated in this area. Prevalence of Borrelia burgdorferi s.l. complex comprised 9.33%. Genospecies B. afzelii and less frequently B. garinii were detected. A mixt-infection with two Borel-lia species was detected in one sample. Interestingly, all Borrelia-infected ticks belonged to I. persulcatus suggesting a closer association for certain species in «pathogen-vector» system. Our findings are essential in investigating distribution of ixodid borreliosis foci in St. Petersburg and suburbs, obtaining new data regarding epidemiology, diagnostics, treatment and prevention of this infection. It is noteworthy than prevalence of pathogenic Borrelia spp. vs. tick-borne encephalitis virus in vectors was higher thereby accounting for its higher morbidity. Comparing our data with those published elsewhere by European researchers allows to note that prevalence of pathogenic Borrelia spp. in ticks varies broadly in diverse geographic regions. It is necessary to take into consideration that prevalence of Borrelia markers achieves ~10% in ticks given frequent attendance of park areas near St. Petersburg that point at risk of developing bor-reliosis in recreational zones.

Serosurveys for IgG antibodies to Borrelia burgdorferi sensu stricto in a population exposed to tick bites (n = 247) and blood donors (n = 114) were done to assess the prevalence of tick-borne infections in. Seroprevalence of antiborrelial IgG antibodies was estimated in 0.6–7.2 % and 0 % of risk population and blood donors, respectively. While previous expositions to A. phagocytophilum (7.2 %), E. chaffensis (3.6 %) and B. microti (11.5 %) were serologically detected. These reports suggest the presence of tick-borne pathogens in Cuba, nonetheless lacking of further accurate information strongly calls to the need of more deeply studies. Cuba

The article sums up long-term, researches of studying of species and genetic variety of tick infections pathogens in combined, natural focuses of the Eastern Siberia. The results of the research testify to the high genetic variety of regional population, of tick-borne encephalitis virus that is represented, by the strains of Far-Eastern, West, Ural-Siberian genotypes, the strains of the group 886 and. 178-79. Infection of Ixodidae by the next pathogens: B. garinii, B. afzelii, R. sibirica, R. raoultii (генотипы. R. sp. DnS14, R. sp. DnS28), E. muris, A. phagocytophilum и Candidatus «Neoehrlichia mikurensis» was determined.

PCR assays were used to test sample from Ixodes persulcatus, blood and tissues of small mammals, human blood after tick bi- tes, as well as isolates from adult ticks. It was demonstrated the presence of two Borrelia species: B. garinii and B. afzelii. Mainly DNA B. garinii NT29 were determined.

Ixodes tick-borne borrelioses (ITBB) are caused by two different spirochetes: Borrelia from the group of Borrelia burgdorferi sensu lato, the agents of the classic Lyme borreliosis (LB), and Borrelia miyamotoi that belongs to the group of Borrelia causing tick-borne relapsing fevers. ITBB caused by B. miyamotoi (BM-ITBB) is a previously unknown infectious disease discovered in Russia. It is known that the LB sequelae may reduce the long-term life guality of convalescents., Aim: To study the follow-up of those who have recovered from new BM-ITBB infection in comparison with persons who have had LB., Subjects and Methods: The investigation enrolled 41 patients with BM-ITBB and 41 patients with LB who were treated at the Republican Infectious Diseases Hospital of Udmurtia. Within a year after the disease, they were followed up through clinical and instrumental examination of cardiac performance, expanded biochemical analysis of blood and urine, which could; estimate kidney and liver functions, and psychological questioning., Results: Asthenic syndrome and complaints about and objective signs of cardiac dysfunctions persisted supraventricular extrasystoles, left ventricular diastolic dysfunction, and elevated and/or unstable systolic blood pressure were detected in 20-30% of the convalescents for a long time. Kidney dysfunctions were manifested in albuminuria and the decrease of glomerular filtration rate. A year following the disease, 10-20% patients had persistently elevated concentrations of alanine aminotransferase, aspartate aminotransferase, and C-reactive protein and had higher levels of total cholesterol and low-density lipoproteins. The pathological consequences of ITBB were polymorphic and varied in different patients; in general, only 68% of them showed health improvement., Conclusion: We assume that a significant role in the pathogenesis of BM-ITBB and LB is played by vascular endothelial damage possibly associated with the inflammatory and autoimmune aspects of an immune response in Borrelia infection. The consequences of this damage may persist and even intensify during a year, which provokes chronic dysfunction of the heart, kidney, or liver in a number of convalescents.

It is known that among biological mutagenic factors the cytogenetic aberrations can be induced by not only intracellular parasites like viruses, but also some extracellular infectious agents including bacteria, protozoas and helminthes. The object of this work was to study the cytogenetic status of acute Lyme borreliosis patients. It was found that the acute Lyme borreliosis patients as compared with the control group showed significantly higher frequencies of lymphocytes with chromosome instability in the peripheral blood mononuclear cell cultures. Chromosome instability included the aneugenic type like polyploidy, hypoploidy or endoreduplication as well as the clastogenic type like chromatid and chromosomal breaks. In addition, high chromosome abnormality frequencies in the patients' cultures were associated with an increase in elimination of the abnormal cells by apoptosis.

A study of possible transovarial and transphase transmission of borreliae by the tick Dermacentor reticulatus is carried out. The possibility of borreliae transmission by the ticks of this species being infected spontaneously as well as experimentally is shown in principle. Although borreliae are preserved in the organism of D. reticulatus, low values of the infestation are established in the different stages of D. reticulatus development and in all steps of the study. D. reticulatus may be involved in the process of borreliae circulation in natural foci of tick-born borreliosis, but this species has no a significant importance for the maintenance of it.

The paper describes a case of a long-lasting chronic migrant erythema (ME) in an 82-year-old female, which developed after the bite of an insect (a tick?). The specific feature of this case is an unusual duration (2 years) of a single focus of ME and autopsy of the skin revealed giant cells with centrally arranged 3-5 nuclei and cytoplam with PAS-positive inclusions as tiny (5 m) oblong formations, that may be Borelia.

Laboratory tests have established a high activity and long-term persistence of some cipermethrin isomers (fendone, fastac) and cifluthrin (zolfac) against the tick Ornithodoros papillipes, a carrier of tick-borne relapsing fever. These indices are considerably superior to those of an isomer mixture of cipermethrin (cimbush, ripkord). This can be applied to deltamethrin and cigalothrin. The findings suggest that these agents are highly promising in controlling the carrier of tick-borne relapsing fever along with a significant reduction in the ecological pesticidal load in the focus.