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The unfavorable epidemiological situation with tick-borne vector-borne infections may be characterized not only by an increase in the occurrence of already known diseases, but also by the identification of new infections and pathogens, the role of which remains poorly understood. An example of such pathogens is Yanggou tick virus (YGTV), which belongs to the group of segmented flavi-like viruses.The aim. To detect and molecular genetic characterization of YGTV found in Dermacentor nuttalli Ol. (1929) ticks on the territory of the Republic of Buryatia.Materials and methods. The study analyzed 350 individual samples of adult ticks of D. nuttalli species collected in the spring-summer period of 2023 on the territory of five districts of the Republic of Buryatia. The detection of YGTV RNA was performed by PCR followed by nucleotide sequence determination and phylogenetic analysis for each of the 4 genome segments.Results. In one sample of the tick D. nuttalli, collected in the Ivolginsky district of the Republic of Buryatia, YGTV RNA was detected, which was further confirmed by sequencing of the obtained genome fragment. The incidence of YGTV RNA among the studied D. nuttalli ticks in Buryatia was 0.3 % (95 % CI: 0.1–1.6). Primers were designed to obtain fragments of all four segments of the YGTV genome. The identified genetic variant of YGTV, when analyzed phylogenetically across all four segments, clearly clusters with YGTV sequences found earlier in China and Russia (the Republic of Altai and Tyva). The detected variant shows the highest sequence identity with the prototype strain Erzin14-T20074.Conclusion. The study shows for the first time the presence of YGTV in the territory of the Republic of Buryatia, which actualizes the need to monitor the circulation of this virus in natural foci of tick-borne infections in this territory, as well as to further clarify the boundaries of the spread of flavi-like viruses potentially dangerous for humans.

Relevance. Hepatitis B often causes liver cirrhosis and hepatocellular carcinoma, especially among patients with HIV. Vaccination is the main prophylaxis of HBV for preventing infection and developing chronic disease. Studying the duration of postvaccination immunity and the expediency of revaccination in different age and risk groups is important for improving the strategy of immunoprophylaxis of B hepatitis.Aims. Study was to determine the level of post-vaccination immunity to HBV and specific antibodies (anti-HBc and anti-HBs) among HIV-positive patients and the healthy population of Novosibirsk and Tomsk.Materials and methods. 536 blood samples were taken from HIV-positive patients and 337 blood samples from healthy people (pregnant women and persons undergoing a routine medical examination). The presence of HBsAg, anti-HBs IgG, and anti-HBcIgG were determined in the samples.Results. The proportion of post-vaccination immunity decreased in older age groups with an increase in the proportion of post-exposure immunity. The proportion of HIV-positive patients who had contact with HBV was higher than among healthy people. Around 70% of people in each group had a low level of protective antibodies anti-HBs (lower than 100 IU). A high level of anti-HBs (higher than 400 IU) was determined in 10% of examined people. The proportion of low levels of anti-HBs increased with age, while average and high levels of post-vaccination immunity were less common with increasing age.Conclusion. A low proportion of HIV-positive people, who have been effectively vaccinated against hepatitis B, was noticed. Annual blood tests for the presence of HBsAg, anti-HBs, and anti-HBc, in combination with determining DNA HBV, can be recommended for HIV-positive patients who have a risk of developing an occult form of hepatitis B.

Nipah virus (Nipah virus, NiV) is a representative of the genus Henipavirus of the Paramyxoviridae family, the causative agent of a dangerous infectious disease with a wide range of clinical manifestations – from an asymptomatic (subclinical) form to severe encephalitis with fatal outcome. Despite the fact that the disease caused by this virus is registered only in the countries of Southeast Asia, the possibility of importing the pathogen to non-endemic territories is not excluded. Also, this pathogen is able to infect not only a large number of people, but also animals, causing serious diseases and significant economic damage, posing both, a medical and veterinary problem. This review presents the data available in the modern press on the structure and classification of the Nipah virus, possible cycles of its transmission, spread, methods of indication and identification in clinical and biological material, as well as the effectiveness of their use depending on the timing of the onset of the disease and available commercial diagnostic and preventive drugs.

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.

The most common anthropozoonoses on the African continent are coxiellosis and Rift Valley fever. It is known that detection of specific IgG antibodies in the blood sera of farm animals is one of the indicators of the pathogen circulation in a certain territory. The aim of the work was to identify specific IgG antibodies in the blood sera of farm animals collected on the territory of the Republic of Guinea to pathogens of zoonotic infectious diseases: coxiellosis, brucellosis, glanders, CCHF, West Nile and Rift Valley fevers, using enzyme immunoassay (ELISA). Materials and methods. A panel of 970 samples of blood sera from farm animals inhabiting all landscape-geographical zones of Guinea was compiled for the work. Identification of specific antibodies was carried out using enzyme immunoassay with preparations recommended for veterinary studies. Results and discussion. Specific antibodies to zoonoses were detected in 700 out of 1074 samples (65.2 % of the total), including: to Coxiella burnetii – in 172 (16.0 %); to Brucella spp. – in 212 (19.7 %); viruses of Rift Valley fever – 85 (7.9 %); CCHF – in 139 (12.9 %) and West Nile fever – in 92 (8.6 %). Antibodies to Burkholderia mallei were not found in the tested material. Positive samples were registered in all landscape-geographical zones. Thus, an urgent task is to continue studying the circulation of pathogens of zoonoses and anthropozoonoses in the territory of the Republic of Guinea and to organize regular monitoring over the spread of zoonotic infectious diseases in collaboration with veterinary services, which will allow timely forecasting and coordinating prophylactic (anti-epidemic) measures to prevent cases of diseases.

Yellow fever is an acute infectious disease of viral nature, the causative agent of which is vector-borne –is transmitted through the bites of infected mosquitoes. Massive epidemics caused by the yellow fever virus are observed in the countries of Africa, South and Central America annually. Imported cases are also registered in non-endemic territories. The review presents the currently available data on the distribution, structure and classification of the yellow fever virus, the identification of its genetic variants depending on the geographical distribution, as well as modern methods of detection and identification of the pathogen in samples taken from sick and dead people. It considers the possibility of using virological, immunoserological and molecular-genetic methods for the diagnosis of yellow fever in different periods from the onset of the disease and in retrospective studies. The lists of diagnostic drugs of domestic and foreign production for the detection of agent markers (antigen, RNA), as well as specific antibodies of IgM and IgG classes, approved for use on the territory of the Russian Federation, are provided. The relevance of further development, improvement and introduction into laboratory practice of reagent kits that allow to detect the yellow fever virus in samples from sick people in a short time, with high efficiency and specificity is demonstrated. This will help to establish a diagnosis promptly and conduct timely anti-epidemic measures, as well as to determine the level of the population stratum immune to the pathogen in endemic regions and evaluate the effectiveness of immunization for the vaccinated contingent.

Over the last years, an increasing rate of ixodes tick bites has been registered in the northern regions of the European Russia. In addition, the number of subjects request medical assistance due to tick bites has been dramatically increased in the Komi Republic. In addition, incidence of tick-borne encephalitis was also increased particularly starting since 2009. However, highly limited data on pathogen genetic diversity related to viral tick-borne infections in this region are currently available. Taiga ticks (Ixodespersulcatus) collected from the Komi Republic southern and central part vegetation were examined to identify and genotype tick-borne viruses. Individual ticks were used to identify by RT-PCR viral RNA coupled to tick-borne encephalitis and Kemerovo viruses. Viral genome fragment sequencing allowed to unambiguously identify these viruses. It was found that viral RNA tick-borne encephalitis was detected in 6.8±1.2% individual ticks. Moreover, tick-linked isolate genotyping based on analyzing E protein gene fragment nucleotide sequence derived from tick-borne encephalitis discovered that 35% and 65% isolates belonged to the Far Eastern and Siberian subtype, respectively. In addition, subsequent phylogenetic analysis demonstrated that at least four variants of the Siberian and Far Eastern subtypes of tick-borne encephalitis virus were detected, which were close to the viruses circulating in the Urals and Siberia. In contrast, prevalence of Kemerovo virus in taiga ticks was 0.8±0.2%. Sequencing of Kemerovo virus RNA-dependent RNA polymerase gene fragment showed around 94% homology with the remainder of the Kemerovo virus strains. Phylogenetic analysis of the Kemerovo virus genome fragments demonstrated at least two subtypes circulating in the Komi Republic. Thus, it was suggested that tick-borne encephalitis virus was introduced relatively recently from the Urals and Siberian region into the natural foci of the Komi Republic. Moreover, genetic differences found in Kemerovo virus strains presume for them a longer lasting evolution throughout the natural foci of this region. In addition, a potential role for birds and their ticks in rapid spreading of viral tick-borne infections in the Komi Republic is also discussed. Thus, the data on genetic diversity of the viral agents related to tick-born encephalitis and Kemerovo fever may be useful for improving their diagnostics, prevention and treatment in the Komi Republic.

Introduction. The detection of the first cases of tick-borne human granulocytic anaplasmosis in Russia, discovery of genetic markers for Anaplasma spp. in ixodid ticks and reporting of a significant number of cases of tick-borne infections in the southern part of Western Siberia give reason to suppose that causative agents of tick-borne anaplasmosis may be transmitted in Tomsk and its suburbs. Objective. To study the distribution and species biodiversity of A. phagocytophilum in ixodid ticks in Tomsk Region. Materials and methods. The analysis of 690 individual ixodid ticks (larvae and adults) was carried out for Ixodes persulcatus (n = 530) and Dermacentor reticulatus (n = 160) ticks collected in 2015–2016 on the territory of urban and suburban biotopes of Tomsk. Primary screening of ticks for the presence of genetic material of A. phagocytophilum was conducted using two-round PCR with species-specific primers for the 16S rRNA gene. The amplification (1,220 kB) of the groESL fragment of the heat shock protein operon was performed for positive isolates with subsequent determination of the nucleotide sequence in the gene fragment for phylogenetic analysis. Results. The number of A. phagocytophilum positive samples for I. persulcatus (larvae) was 1.2 ± 0.6%, I. persulcatus (adult) was 1.8 ± 0.7%; and D. reticulatus (adult) was 0.6 ± 0.3%. Analysis of the nucleotide sequence of the gene fragments in groESL operon for nine isolates confirmed that the genetic material of the granulocytic anaplasmosis was detected. Phylogenetic analysis showed that all the isolates belonged to the first group of the “new cluster” of A. phagocytophilum. Conclusion. The causative agent of human granulocytic anaplasmosis has been newly detected in I. persulcatus ticks collected in urban and suburban biotopes of Tomsk and in D. reticulatus from urban foci.