СТРУКТУРА СООБЩЕСТВ И РАСПРОСТРАНЕННОСТЬ ГЕНЕТИЧЕСКИХ МАРКЕРОВ ВОЗБУДИТЕЛЕЙ ТРАНСМИССИВНЫХ ИНФЕКЦИЙ У ИКСОДОВЫХ КЛЕЩЕЙ, СОБРАННЫХ С РАСТИТЕЛЬНОСТИ И СНЯТЫХ С ЛИЦ, ПОСТРАДАВШИХ ОТ ПРИСАСЫВАНИЯ НА ТЕРРИТОРИИ ТЮМЕНСКОЙ ОБЛАСТИ

Introduction. Tomsk region is one of the territories of the Russian Federation with the highest possible incidence of tick-borne infections. However, the spectrum and genetic diversity of tick-borne pathogens remain insufficiently studied. Materials and methods. The study analyzed 534 ticks: Ixodes persulcatus (n = 107), I. pavlovskyi (n = 234) and Dermacentor reticulatus (n = 193), collected in 13 biotopes of Tomsk and its suburbs during 2023. Detection of genetic material of tick-borne pathogens was carried out by PCR and RT-PCR in individual ticks with subsequent sequencing and phylogenetic analysis of nucleotide sequences. Results. More than fourfold dominance of I. pavlovskyi and D. reticulatus ticks over the taiga tick was observed. Infection of I. persulcatus ticks with tick-borne encephalitis virus (TBEV) of the Siberian genotype amounted to 1.3%, in ticks of the Ixodes genus, the genetic material of Borrelia burgdorferi s.l. was detected in 8.5%, B. miyamotoi – in 2.1%, Anaplasma phagocytophilum — in 1.5%, and Rickettsia tarasevichiae — in 14.1%. R. raoultii infection of D. reticulatus ticks was identified in 48.7%, and Babesia canis DNA was detected in a single sample. Genotyping and phylogenetic analysis of genomic nucleotide sequences showed the presence of new, unusual for the region genetic variants of B. garinii, B. bavariensis, B. afzelii and the Siberian TBEV genotype (subclade V). Conclusion. In the territory of Tomsk and its suburbs, genetic material of 9 species of tick-borne pathogens, including their new genetic variants, was detected in ixodes ticks.

The profile of infectious agents was studied in individual examination of ticks collected in the south of Primorsky Territory: on the islands of Petra Velikogo Bay in the Sea of Japan (Askold, Popova, Reineke, Rikorda, Russky) and the adjacent mainland territory (Botanical Garden FEB RAS in Vladivostok City). Ticks were collected from vegetation using a flag. On the mainland near the Botanical Garden in 2023–2024, three species of ixodid ticks (Ixodes persulcatus, I. pavlovskyi and Haemaphysalis japonica) were identified, with I. persulcatus predominating. We have shown that, compared to data from the first twenty years of the 20th century, the proportion of I. pavlovskyi in this area has increased from 3 % to 11 %. Five species of ticks were recorded on the islands studied: I. persulcatus, I. pavlovskyi, H. japonica, H. concinna, H. longicornis. Ticks of the genus Ixodes are dominant on Russky and Popov Islands, and Haemaphysalis on Askold Island. In all cases, tick communities are bidominant. Few ixodid ticks were collected due to poor weather on Reyneke and Rikord Islands, preventing a description of the community structure. This study of infectious agents profile in 460 speciments using individual PCR assay from five species (I. persulcatus, I. pavlovskyi, H. japonica, H. concinna, H. longicornis) of ixodid ticks collected in the south region of Primorsky Krai during 2023-2024. Infection with tick-borne encephalitis virus (0,8 %), Borrelia (20,8 %), Ehrlichia (0,4 %), and Anaplasma (1,9 %) was shown. Moreover, сo-infection of individual ticks with two pathogens simultaneously in 0,9 % cases was identified. In addition, tick-borne encephalitis virus and ixodid tick-borne borreliosis pathogens is higher in tick samples from Russky Island in contrast of another Island and on the mainland. Two tick-borne encephalitis virus isolates corresponding to Siberian subtype from ticks of the genus Ixodes that was collected on the Russky Island. One tick-borne encephalitis virus isolates from the I. pavlovskyi tick in Island Ricorda. On the territory of the Botanical Garden and Russian Island three types of pathogenic Borrelia have been identified: the group Borrelia burgdorferi s.l. (B. afzelii and B. garinii) and B. miyamotoi Two species of Rickettsia was identified: Candidatus R. tarasevichiae from I. persulcatus and Candidatus R. principis from the tick H. japonica.

diagnosed cases ranged from July 20 to October 4, 2009. Cases peaked in early September and subsided in early October. The median age of patients with confi rmed or probable disease was 47.3 years (range 3-96 years). Infections occurred in all age groups, but most infections occurred among persons 41 to 65 years of age; 118 (60.2%) were women, and 172 were farm workers. Confi rmed and clinically diagnosed cases occurred in 18 villages, which were part of 7 towns. Most cases (182) were reported in Yiting, where the fi rst case was confi rmed, and in particular, were in persons who lived in the villages of Qingsu, 100 cases; Fantianzhu, 49 cases; Xitian, 19 cases; Shangzhai, 4 cases; and Xiateng, 4 cases.

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.

Tick-borne encephalitis virus (TBEV) is traditionally divided into three main subtypes - European (Eu), Siberian (Sib) and Far Eastern (FE), the distribution of which is confined to the areas of the main vectors, Ixodes ricinus (TBEV-Eu) and Ixodes persulcatus (TBEV-Sib, TBEV-FE). Dermacentor reticulatus also can act as competent vector and participate in TBEV circulation together with the main vectors. It is suggested that there is a specific adaptation not only between TBEV variant and certain tick species, but also between virus variant and local populations of one tick species. In our study, we percoxally infected two populations of I. ricinus, I. persulcatus and D. reticulatus collected in remote areas with three TBEV strains of the main subtypes. Dynamics of the number of TBEV RNA copies and of the number of infectious for mammalian cells virus particles during mono- and mixed infection of ticks were estimated by real-time PCR and plaque assay in PEK cell culture, respectively. Data was obtained that I. ricinus, I. persulcatus and D. reticulatus effectively support the reproduction of TBEV regardless of the strain. Interpopulation differences of local populations of one tick species in the maintenance of TBEV reproduction were revealed in I. persulcatus during mono- and mixed infection and in I. ricinus during mixed infection. Despite minor differences in the level of virus reproduction in ticks, we observed changes in the infectivity of TBEV strains for mammalian cell culture during persistence in different species of ticks. Notably, the TBEV-Eu increased infectivity during adaptation to a non-specific tick species. Thus, we demonstrated that the level of virus reproduction is not the primary factor that determines the adaptation of TBEV to a new tick species. The nature of changes in TBEV infectivity depends on the virus strain and the species of ticks.

The persistence of tick-borne encephalitis virus (TBEV) in nature is maintained by numerous species of reservoir hosts, multiple transmissions between vertebrates and invertebrates, and the virus adaptation to its hosts. Our Aim: was to compare TBEV isolates from ticks and small wild mammals to estimate their roles in the circulation of the viral subtypes. TBEV isolates from two species of ixodid ticks, four species of rodents, and one species of shrews in the Novosibirsk region, South-Western Siberia, Russia, were analyzed using bioassay, hemagglutination, hemagglutination inhibition, neutralization tests, ELISA, reverse transcription with real-time PCR, and phylogenetic analysis. TBEV RNA and/or protein E were found in 70.9% ± 3.0% of mammals and in 3.8% ± 0.4% of ticks. The TBEV infection rate, main subtypes, and neurovirulence were similar between ixodid tick species. However, the proportions of the virus that were pathogenic for laboratory mice and of the Far-Eastern (FE) subtype, as well as the viral loads with the Siberian and the European subtypes for the TBEV in Ixodes pavlovskyi Pomerantsev, 1946 were higher than in Ixodes persulcatus (P. Schulze, 1930). Percentages of infected Myodes rutilus, Sicista betulina, and Sorex araneus exceeded those of Apodemus agrarius and Myodes rufocanus. Larvae and nymphs of ticks were found mainly on rodents, especially on Myodes rufocanus and S. betulina. The proportion of TBEV-mixed infections with different subtypes in the infected ticks (55.9% ± 6.5%) was higher than in small mammals (36.1% ± 4.0%) (p < 0.01). Molecular typing revealed mono- or mixed infection with three main subtypes of TBEV in ticks and small mammals. The Siberian subtype was more common in ixodid ticks, and the FE subtype was more common in small mammals (p < 0.001). TBEV isolates of the European subtype were rare. TBEV infection among different species of small mammals did not correlate with their infestation rate with ticks in the Novosibirsk region, Russia.

Influence of altitude on tick-borne encephalitis infection risk in the natural foci of the Altai Republic, Southern Siberia

The taiga tick, Ixodes persulcatus, has previously been limited to eastern Europe and northern Asia, but recently its range has expanded to Finland and northern Sweden. The species is of medical importance, as it, along with a string of other pathogens, may carry the Siberian and Far Eastern subtypes of tick-borne encephalitis virus. These subtypes appear to cause more severe disease, with higher fatality rates than the central European subtype. Until recently, the meadow tick, Dermacentor reticulatus, has been absent from Scandinavia, but has now been detected in Denmark, Norway and Sweden. Dermacentor reticulatus carries, along with other pathogens, Babesia canis and Rickettsia raoultii. Babesia canis causes severe and often fatal canine babesiosis, and R. raoultii may cause disease in humans. We collected 600 tick nymphs from each of 50 randomly selected sites in Denmark, southern Norway and south-eastern Sweden in August–September 2016. We tested pools of 10 nymphs in a Fluidigm real time PCR chip to screen for I. persulcatus and D. reticulatus, as well as tick-borne pathogens. Of all the 30,000 nymphs tested, none were I. persulcatus or D. reticulatus. Our results suggest that I. persulcatus is still limited to the northern parts of Sweden, and have not expanded into southern parts of Scandinavia. According to literature reports and supported by our screening results, D. reticulatus may yet only be an occasional guest in Scandinavia without established populations.

This expert opinion considers only the most significant aspects of the impact of climate change on ticks and tick-borne diseases in Russia. Attention is focused on the species that are most widespread in the extratropical part of the northern hemisphere: the taiga tick, Ixodes persulcatus, and the European forest tick, I. ricinus, which are hosts and vectors of tick-borne encephalitis (TBE) virus and Borrelia spirochaetes, agents of ixodid tickborne borrelioses (ITBBs), i.e. of Lyme and Lyme-like diseases.

Tick-borne encephalitis (TBE) is the medically most common tick-borne viral disease in Europe and Asia. The TBE virus (TBEV) is a member of the family Flaviviridae. Transmission mainly to humans occurs by ticks of the Family Ixodidae, mainly the castor bean tick (Ixodes ricinus) in Europe and the taiga tick (Ixodes persulcatus) in Asia. Rarely TBEV is also transmitted by contaminated milk of infected ungulates (goat, sheep, cow). The clinical course of TBE is variable and may range from subclinical to fatal encephalomyelitis. Probably host and viral factors are involved in the pathogenesis of disease. So far, no specific treatment of the disease is available. The only effective prevention of TBE is vaccination. A number of different vaccines are available worldwide. In Europe two vaccines are licensed which contain inactivated European subtype TBEV. Probably the European vaccines protect also against infections with other subtypes of TBEV.

This article deals with the peculiarities of distribution of ixodid ticks on small mammals in the northern, middle, southern taiga and subtaiga of the West Siberian Plain. Representatives of 7 species of ixodid ticks were found to inhabit the area:Ixodes persulcatus,I.apronophorus,I.trianguliceps,I. pavlovskyi,Dermacentor reticulatus,D.marginatus,D.silvarum. Species diversity decreases from south to north. In the northern taiga and middle taiga subzones, populations of two species were found –I.persulcatusandI.apronophorus. In addition to these two species, the larva ofI.triangulicepswas found in the southern taiga. The sub-taiga subzone is characterized by the presence of seven species of ixodid ticks. In general,I.persulcatuswas the most abundant within the taiga zone, and its proportion in different subzones ranged from 41 to 85%. In some areas of the middle taiga, its dominance could reach 99% in the structure of ixodid communities. Cases of hyperinvasion by ticks were observed in individual host individuals – their number varied from 52 to 195 individuals. Such significant infestations were most often observed in representatives of the background species of small mammals – northern red-backed vole, common shrew, and occasionally on the common hamster.

Ticks are important parasites of economic and public health because of their ability to transmit zoonotic diseases. Tick-borne encephalitis virus (TBEV), now officially Orthoflavivirus encephalitidis, is a Flavivirus with five main subtypes of which three, the European (TBEV-EU), the Siberian (TBEV-Sib), and the Far-Eastern subtypes (TBEV-FE), are supposedly circulate in Latvia. Several hard tick species are involved in TBEV circulation and transmission in nature. This study set out to describe the genetic landscape of TBEV subtypes in Latvian tick populations. In 2019 and 2021 to 2023, a total of 3026 ticks were collected in three Latvian regions, with Ixodes ricinus as the dominant species (2822 specimens), followed by Ixodes persulcatus (200 specimens) and Dermacentor reticulatus (4 specimens). Ticks were morphologically identified, pooled, and screened for TBEV RNA by RT-qPCR. TBEV of positive tick pools were isolated and genetically characterized by genome sequencing. Our study demonstrates the prevalence of two TBEV subtypes in Latvia with specific spatial patterning. In the sympatric Vidzeme region, these subtypes display a preferential species association of TBEV-EU with Ixodes ricinus and TBEV-Sib with Ixodes persulcatus. Phylogeographic analysis suggests independent introductions of multiple genotypes from both subtypes. Further investigations are necessary to better understand the natural transmission and the medical importance of these TBEVs.

The objects of this study are Ixodes ticks which were collected in different areas of Kirov province. The aim of the study is to determine the proportion of TBEV infected ticks using the reverse transcription and PCR, dependingon time, place, and methods of collection in the Kirov province as well as of ticks specific and sexual identity. The study found that from the two tick species that were tested only taiga tick (Ixodes persulcatus) but not the meadow thick (Dermacentor reticulatus) was the TBEV vector. Study also has shown that both males and females ticks can be the TBEV vectors. Moreover, it was proved the importance of ticks testing which were gathered not only from human but also from animals, primary from dogs, and from the plants.

The Louisiana Gulf Coast consists of the 38 southern parishes and the 16 continental shelf areas off-shore. Oil and gas production is obtained from sediments ranging in age from Cretaceous to Pleistocene. The 2,236 development and exploratory wells drilled in 1962 are 2.3% more than were drilled in 1961. Of the 600 exploratory wells, 17.0% were successful. For the first time in several years the Southwest District was the most active in exploratory drilling. Of the 43 new-field discoveries (27 onshore, 16 offshore) the most important are: Money Island, Cameron Parish; Mud Point, Vermillion Parish; Block 112 field, Main Pass Area; Block 225 field, Block 229 field, West Cameron Area; and Block 41 field, West Delta Area. The most important of the 240 new pools and extensions include Couquille Bay field, Plaquemines Parish; Eloi Bay field, St. Bernard Parish; and Lake Barre field, Terrebonne Parish. Geophysical activity showed a slight increase for the first time in several years. Leasing continued to be very active but scattered. In general, 1962 compared favorably with 1961 and preceding years.

Surveillance of tick-borne encephalitis virus in wild birds and ticks in Tomsk city and its suburbs (Western Siberia)