Detection of Borrelia miyamotoi in Ixodidae Ticks Collected in the South of Western Siberia

Objective of the study was to assess the level of infection with Borrelia miyamotoi in ticks Ixodes persulcatus and Ixodes pavlovskyi collected in the south of Western Siberia.Materials and methods. 688 ticks I. persulcatus and I. pavlovskyi collected on the territory of Novosibirsk, Tomsk and Kemerovo Regions were examined. Borrelia DNA was detected by a two-round polymerase chain reaction with specifc primers to the omp66 gene region, followed by sequencing of the isolated fragments and phylogenetic analysis, including the sequences of prototype isolates published in the international GenBank database. Comparison and analysis of nucleotide sequences was carried out using the MEGA 7 software package. In parallel, the samples were examined for the presence of the agents of transmissible infections – West Nile fever and tick-borne encephalitis, anaplasmosis, ehrlichiosis, babesiosis, bartonellosis and candidate pathogens of tick-borne rickettsiosis through RT-PCR and PCR with species-specifc and genus-specifc primers.Results and discussion. The genetic material of B. miyamotoi was found in 2.2 % of I. persulcatus and I. pavlovskyi ticks in the Tomsk, Novosibirsk, and Kemerovo Regions and their appurtenance to the Asian genotype was determined. It was revealed that the degree of similarity of the omp66 gene fragments within the group of isolates of the Asian genotype was 100 %. No relation between B. miyamotoi and a specifc vector species was identifed.

Role of Ixodes Pavlovskyi (Acari, Ixodidae) in Borreliosis Epizootic Process at the Island Russky

The incidence of Ixodes tick-borne borreliosis (ITBB) at the Island Russky (Primorsk Territory) is higher than at the mainland. There is a bidominant structure of the tick population with mass occurrence of Ixodes persulcatus and I. pavlovskyi at the island. Due to the higher infectivity and aggressiveness of I. persulcatus, it is suggested that it plays a key role in high activity of the ITBB focus at the island.The aim of the study: to characterize the role of I. pavlovskyi in the borreliosis epizootic process based on the study of the structure of the borrelia genotype complex isolated from Ixodes ticks at the Island Russky.Materials and methods. The ticks were collected from vegetation at three sites. Ixodide species were determined morphologically and using PCR for mitochondrial gene cox1 and nuclear multicopy locus ITS2. Infection of 233 ticks was analyzed with the species identification confirmed by all methods. Borrelia genospecies were determined by multiplex two-round PCR with the primers specific to the gene fragments 5S and 23S rRNA of Borrelia burgdorferi sensu lato complex.Results and discussion. Coexistence of I. persulcatus and I. pavlovskyi at the island was confirmed, with different ratios in space and a gradual increase in the proportion of the latter species. The circulation of three etiological agents of ITBB: Borrelia garinii (predominantly in I. pavlovskyi), B. bavariensis and B. afzelii (in I. persulcatus) was identified. Thus, an active natural focus of ITBB has formed at the island, probably including two uninsulated chains of borrelia circulation. One chain combines I. persulcatus and small and large mammals as the tick feeders. The second – I. pavlovskyi that can feed on mammals and birds. Due to the spatial variability of the ixodide population structure at different sections of the island, the ratio of the circulating borrelia species can change, and this species becomes the main vector of the pathogenic agents in areas of I. pavlovskyi absolute dominance.

РАСПРОСТРАНЕНИЕ И НЕКОТОРЫЕ ОСОБЕННОСТИ БИОЛОГИИ ИКСОДОВЫХ КЛЕЩЕЙ (PARASITIFORMES, IXODIDAE) В К03НЕЦКО-САЛАИРСКОЙ ГОРНОЙ ОБЛАСТИ (КЕМЕРОВСКАЯ ОБЛАСТЬ, РОССИЯ), "Паразитология"

В статье представлены обобщенные результаты собственных исследований и анализ литературных источников по распространению и некоторым особенностям биологии различных видов иксодовых клещей на территории Кузнецко-Салаирской горной области. Выделены группы наиболее многочисленных видов клещей, представляющих эпидемиологическую угрозу. Установлено изменение доминирования Ixodes pavlovskyi и I. persulcatus на разных территориях. Приведены сведения об основных прокормителях клещей сем. Ixodidae в регионе.

Distribution of the tick-borne encephalitis virus among naturally infected ixodid ticks and small mammals in the Novosibirsk region

A comparative analysis of the virus infection carrier state and distribution of genetic types of the virus of tick-borne encephalitis (TBE) among invertebrates (2 species of ticks, Ixodes persulcatus Schulze and Ixodes pavlovskyi Pomerantsev 1946) and vertebrate reservoir hosts (4 species of small rodents: the red vole Myodes rutilus Pallas, gray-sided vole Myodes rufocanus Sundevall, field mouse Apodemus agrarius Pallas, birch mice Sicista betulina Pallas and 1 species of insectivores - common shrew Sorex araneus L (1758)), dominating on the territory of the Novosibirsk region in 2009-14 years, was performed with the use of virological and molecular biological methods. Frequency detection of RNA and / or E protein in mammals (70,9 ± 3,0%) were shown to considerably exceed levels of virus infection carrier state rate of ticks (3,4 ± 0,4). In the circulation of three major types of TBE - Far East (FE), Siberian (NIB) and European (Eur) in natural populations in mono - or polytype forms in mites Sib type prevailed (p