Epidemiological Situation on Tick-Borne Spotted Fever Group Rickettsioses in the Russian Federation in 2012–2021, Prognosis for 2022–2026

The aim of the review was to characterize the epidemiological situation on rickettsiosis of the tick-borne spotted fever (TSF) group in the constituent entities of the Russian Federation in 2012–2021 and provide a long-term forecast for 2022–2026. In 2020–2021, indicators of registered incidence of tick-borne rickettsiosis in Russia on the whole decreased relative to the average long-term pre-pandemic level in 2012–2019 by 2 fold for all forms of the TSF group on average (Siberian tick-borne typhus – STT, Astrakhan spotted fever and Mediterranean fever). A comparative analysis of the territories revealed a correlation between the incidence of STT and the number of medical facility visits due to “tick bites” (r=0.67, p=0.015), which, against the background of an increase in the frequency of contacts of the population with vectors in 2020–2021 in most regions and a decrease in the incidence in the same regions indicates the credible nature of the changes. The ranking of territories according to average long-term incidence rates made it possible to classify the Republic of Altai and the Altai Territory as regions of extremely high epidemic hazard as regards STT; high hazard – the Republic of Tuva; above average – the Republic of Khakassia, Khabarovsk Territory and the Jewish Autonomous Region. The established downward trend in the incidence of tick-borne rickettsiosis among the population will be sustained in most entities of the Russian Federation within the next 5 years, excluding the Republic of Altai, the Altai Territory, the Republic of Crimea and the city of Sevastopol, where current incidence or an increase should be expected. The results of the analysis indicate the need to put more emphasis on natural-focal infections at the time of COVID-19 pandemic

Review of Epidemiological Situation on Rickettsioses in the Russian Federation in 2022 as Compared with 2013–2021, Forecast for 2023

The aim of the review was to characterize the epidemiological situation on tick-borne rickettsioses (TR) in the Russian Federation in 2022 in comparison with the pandemic years of 2020–2021 and the pre-pandemic period of 2013–2019, to give the forecast for 2023. During 2013–2022, a pattern was observed in the incidence of rickettsiosis of the tick-borne spotted fever group (with the exception of Astrakhan spotted fever – ASF), that is also characteristic of most other natural focal infections (NFIs): a sharp decrease in registered incidence rates in 2020–2021 with the subsequent increase in 2022 almost up to pre-pandemic levels or even exceedance in some regions. The absence of a defining influence of the frequency of contacts of the population with vectors on the decrease in the incidence in the period of 2020–2021 and the rise in the value in 2022 confirms the registration-related nature of the changes. Given due attention to the problem of effective detection and reporting of NFIs, we expect the incidence of tick-borne rickettsioses to remain within the confidence intervals of long-term average values in most endemic regions in 2023. Relaxed vigilance to the problem of NFIs may lead to a decline in the reported incidence of Siberian tick-borne typhus in the Krasnoyarsk and Zabaikalsky Territories, Republics of Tuva and Khakassia, Novosibirsk and Amur Regions; reduction in the incidence of ASF in Astrakhan Region. The main issue in detecting and registration of the tick-borne rickettsiosis incidence, objective assessment and forecasting of the epidemic situation as regards this group of infections is conditioned by the lack of domestic certified diagnostic test kits for laboratory verification of rickettsioses. Close cooperation between epidemiologists and clinicians is required to establish and register cases of TR based on clinical and epidemiological data

Application of Molecular Typing Methods for Analysis of Strains of Rickettsiae of the Spotted Fever Group and Rabies Virus

50 strains of spotted fever group (SFG) rickettsiae and 36 lyssaviruses strains from the collection of Omsk Research Institute of Natural Focus Infections were identified and typed using the approaches of molecular biology, epidemiology and bioinformatics. The taxonomic status of the studied cultures of SFG rickettsiae was identified. Zonation of the Russian Federation territories according to the spread of SFG pathogenic rickettsiae in their hosts - ixodic ticks was carried out. Lyssaviruses distribution in the territory of Siberia was considered

THE PRESENT STATE OF THE PROBLEM OF RICKETTSIOSES IN RUSSIA AND NEW APPROACHES TO THE CLASSIFICATION OF DISEASES CAUSED BY SPOTTED FEVER GROUP RICKETTSIAE

The paper presents analysis of the development and the current status of the doctrine about rickettsia and rickettsiosis. Progress in the study of Rickettsia is associated with, improved methods for their detection and isolation - using live biotechnological systems (cultivation in the experimental lines of ticks-sensitive lines of eukaryotic cells) in combination with methods of genotyping and. classical ricketsial methods. The development and. use of new methodological approaches to the study of tick-borne rickettsiae and other alpha-proteobacteria led to an important revision of ideas about genetic diversity, heterogeneity of antigenic and. biological characteristics, ecology and. contribution to the infectious pathology of various representatives of the order Rickettsiales in Russia

Features of the cultivation of a new genotype of Candidatus Rickettsia tarasevichae in biological models (cell culture, guinea pigs)

This paper presents the results of a study of some phenotypic properties (cultivation in biological models) of a new genotype Candidatus Rickettsia tarasevichae. The experiment was carried out in the eukaryotic cell culture Vero and guinea pigs. For the first time strains of Candidatus Rickettsia tarasevichae were isolated using cell culture. The benign experimental infection (with a primary lesion of cerebral vessels) was reproduced in guinea pigs.В работе представлены результаты изучения некоторых фенотипических свойств (культивирование на биологических моделях) нового генотипа Candidatus Rickettsia tarasevichae. Эксперимент был проведен на эукариотической культуре клеток Vero и морских свинках. Используя культуру клеток, впервые в мире удалось изолировать штаммы Candidatus Rickettsia tarasevichae. На морских свинках была воспроизведена доброкачественная экспериментальная инфекция с преимущественным поражением сосудов головного мозга

Dermacentor reticulatus: a vector on the rise

Dermacentor reticulatus is a hard tick species with extraordinary biological features. It has a high reproduction rate, a rapid developmental cycle, and is also able to overcome years of unfavourable conditions. Dermacentor reticulatus can survive under water for several months and is cold-hardy even compared to other tick species. It has a wide host range: over 60 different wild and domesticated hosts are known for the three active developmental stages. Its high adaptiveness gives an edge to this tick species as shown by new data on the emergence and establishment of D. reticulatus populations throughout Europe. The tick has been the research focus of a growing number of scientists, physicians and veterinarians. Within the Web of Science database, more than a fifth of the over 700 items published on this species between 1897 and 2015 appeared in the last three years (2013–2015). Here we attempt to synthesize current knowledge on the systematics, ecology, geographical distribution and recent spread of the species and to highlight the great spectrum of possible veterinary and public health threats it poses. Canine babesiosis caused by Babesia canis is a severe leading canine vector-borne disease in many endemic areas. Although less frequently than Ixodes ricinus, D. reticulatus adults bite humans and transmit several Rickettsia spp., Omsk haemorrhagic fever virus or Tick-borne encephalitis virus. We have not solely collected and reviewed the latest and fundamental scientific papers available in primary databases but also widened our scope to books, theses, conference papers and specialists colleagues’ experience where needed. Besides the dominant literature available in English, we also tried to access scientific literature in German, Russian and eastern European languages as well. We hope to inspire future research projects that are necessary to understand the basic life-cycle and ecology of this vector in order to understand and prevent disease threats. We conclude that although great strides have been made in our knowledge of the eco-epidemiology of this species, several gaps still need to be filled with basic research, targeting possible reservoir and vector roles and the key factors resulting in the observed geographical spread of D. reticulatus. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-016-1599-x) contains supplementary material, which is available to authorized users

New Approaches in Taxonomy Representatives of Rickettsiales Order

Systematics and nomenclature of representatives Rickettsiales order has always been based on a limited number of available phenotypic characteristics, due to their obligate intracellular localization. Intensive use of «molecular» technology has led to the description of a large number of new species of this taxonomic group, as well as to the reclassification of some of its representatives. Another symbol of the era of «molecular» technology is the emergence of species, genera and families with candidate status («Candidatus») due to the inability of cultivation and studying of biological properties that is required for a valid description of the new species. It should be a legitimate solution to this problem, based on the development and application of new high technologies. This review summarizes recent data on the taxonomy, nomenclature and evolution of representatives order Rickettsiales, new technologies, approaches and methods for the study of certain groups of prokaryotes. Published materials were obtained in the analysis of foreign and Russian scientific publications, as well as on the basis of its own published data. The paper contains a new understanding of the classification within the genus Rickettsia