The aim of the study was to identify genetic features and possible origin of Brucella abortus strains that caused the epizootic outbreak of brucellosis in the Republic of Buryatia in 2023–2024. Materials and methods. The studied B. abortus strains, isolated from pathoanatomical material from cattle in the Republic of Buryatia in 2023–2024 in the area adjacent to Mongolia, were examined bacteriologically, followed by pathogen DNA sequencing and bioinformatic genome analysis. Bayesian phylogenetic analysis was performed in BEAST v2.7.5. Results and discussion. The genomes of the strains have been characterized; a comparative analysis of strain variability has been conducted in relation to the vaccine strain B. abortus 82 and strains isolated in Mongolia in 1999 and 2014. It was established that all studied strains belong to a single clonal branch of B. abortus with sequence type 2. The 2023–2024 outbreak B. abortus group emerged approximately 58 years ago (95% HPD: 31.2–86.7) and is closely related to strains isolated in Mongolia in 1999 and 2014. The evolution rate of this group was 1.8·10–7 substitutions per site per year (95% HPD: 2.5·10–8 – 1.84·10–6 substitutions per site per year). The unique mutation distinguishing this group of strains from B. abortus 82 and Mongolian strains is a defect in the rbsB gene caused by a mutation resulting in a stop codon within the reading frame. This gene is involved in energy-dependent transport of extracellular D-ribose into the cell and may potentially reduce the bacterium’s ability to reproduce inside host cells. As a result of the molecular-genetic study, the causes and patterns of occurrence of the brucellosis outbreak among cattle in the Republic of Buryatia in 2023–2024 has been established.
The aim of this review was to characterize the epidemiological situation regarding tick-borne viral encephalitis (TBVE) in the Russian Federation between 2016 and 2025 and to provide a forecast of TBVE incidence for 2026 for federal districts and constituent entities of the highest epidemiological risk. During 2016–2025, the average annual number of individuals affected by tick bites in the RF was 498575.1. In 2020–2021, an upward trend in this indicator was noted in certain entities of the Volga and Northwestern Federal Districts, among others. Climate warming has shifted the onset of Ixodidae tick activity to the last week of March. A lengthening of the epidemic season is observed. In 2025, 1,807 TBVE cases were identified, corresponding to an incidence rate of 1.24 per 100,000 population (compared to the long-term average of 1.17 per 100,000). The five entities with the highest incidence are Kirov Region, Krasnoyarsk Territory, Tuva Republic, Khakassia Republic, and Perm Territory. A total of 44 fatal outcomes were recorded (case fatality rate – 2.4 %). Based on the data from 2016–2025, 17 entities at highest epidemiological risk have been identified, eight of which are located within the Siberian Federal District. The average tick infection rate in the Russian Federation for 2025 (tested via PCR and ELISA) does not differ from the long-term average. A comparison of the genetic structure of tick-borne encephalitis virus strain samples from 1937–1989 and 1990–2025 has showed an increase in the proportion of the Siberian subtype from 54.8 to 89.7 %, while the ratio of individual genetic lineages within the Siberian subtype remained invariable. The volumes of specific and non-specific TBVE prevention measures in 2025 increased compared to 2024 and corresponded to the target figures in all federal districts. According to the forecast, the TBVE incidence in the Russian Federation in 2026 is projected to be 1.14 per 100,000 population, with a confidence interval from 0.95 to 1.32 per 100,000. An increase in morbidity is possible in the Volga and Far Eastern Federal Districts, while the epidemiological situation in the remaining districts is not likely to change.
In 2024, two cases of community-acquired pneumonia (CAP) imported from Thailand were registered and etiologically deciphered in the Irkutsk Region, including the first case of acute melioidosis resulting in death, which was diagnosed for the first time in the Russian Federation. In the second case, Acinetobacter radioresistens was isolated from a patient with CAP. The aim of the work was to conduct indication and species identification of pathogens causing community-acquired pneumonia, obtained from biological material from patients who had arrived from Thailand to the Irkutsk Region. Materials and methods. The culture of a microorganism isolated from a liver sample of a patient with the fatal outcome, preliminarily identified by mass spectrometry as a causative agent of the genus Burkholderia and clinical material (blood, throat swab, sputum, urine) from a patient with suspected melioidosis were studied. The research was performed using bacteriological, bacterioscopic, molecular-genetic, proteomic, and serological methods of laboratory diagnostics. Results and discussion. In the first imported case, a culture of Burkholderia pseudomallei was isolated from a patient with a postmortem clinical diagnosis of community-acquired bipartite pneumonia; rapid identification of the causative agent of melioidosis was carried out using MALDI-TOF MS and PCR methods. For the purpose of in-depth identification, the isolated culture was studied by a range of laboratory diagnostic methods for melioidosis. The sensitivity of the isolated B. pseudomallei strain to some first- and second-line antibacterial drugs was established, and its species resistance to penicillins, aminoglycosides, and macrolides was confirmed. In the second imported case of community-acquired pneumonia, the causative agent of melioidosis and its DNA were not found in the patient’s clinical material. A culture was isolated from the patient’s urine sample, which was identified by mass spectrometry as Acinetobacter radioresistens. In view of the growing number of imported cases of exotic infections in the Russian Federation, including melioidosis, it is necessary to increase the alertness of medical personnel, incorporate melioidosis in the differential diagnostics of community-acquired pneumonia in people with a “traveler’s history”, maintain the readiness of specialized laboratories, strengthen awareness-raising among the population traveling to regions endemic for dangerous infectious diseases, and ensure effective interdepartmental cooperation within the framework of sanitary protection of the territory of Russia in order to establish an etiological diagnosis of community-acquired pneumonia and correct treatment scheme.
Our communication summarizes the recent changes in the paraphyletic species Orthoflavivirus encephalitidis. The paraphyly arises due to louping-ill virus (LIV), which is genetically closer to the European subtype of tick-borne encephalitis virus (TBEV). To maintain a concept of monophyly, we have split Orthoflavivirus encephalitidis into two monophyletic species: Orthoflavivirus zilberi (after Lev A. Zilber—the head of the expedition that identified and characterized TBEV in the Soviet Far East in 1937) and Orthoflavivirus neudoerflense, named after Neudörfl, a town in Austria where the reference strain Neudoerfl was first isolated. Also, to remove the resulting ambiguity in the virus name “tick-borne encephalitis virus”, we have proposed new names—Asian TBEV (TBEV-AS) for Orthoflavivirus zilberi, and European TBEV (TBEV-EU) for Orthoflavivirus neudoerflense.
Diphtheria is a serious infection, often characterized by a pronounced toxic component, which can be accompanied by severe complications of the cardiovascular and nervous systems. The primary method of infection prevention is immunization (primarily in children) with diphtheria toxoid, which induces effective and long-lasting antitoxic immunity. Objective of the study: evaluation of collective immunity to the causative agent of diphtheria among the population of several regions (Amur, Irkutsk, Nizhny Novgorod, Kaliningrad) and the Republic of Crimea. Materials and methods. The cross-sectional cohort randomized study involved 18,207 people uniformly stratified by age (1–5, 6–11, 12–17, 18–29, 30–39, 40–49, 50–59, 60–69, 70+ years), including: 3,576 in Amur; 3,657 in Irkutsk; 3,580 in Nizhny Novgorod; 3,613 in Kaliningrad regions; and 3,781 in the Republic of Crimea. All studies were conducted in strict accordance with the requirements of the Declaration of Helsinki. Immunoglobulin G Abs to the C. diphtheriae toxin were determined in the examined volunteers by enzyme immunoassay using a Russian-made test system. Data analysis and statistical processing were carried out using a web application. Results. The average cohort regional seroprevalence levels were: Amur Region - 82.3% (95% CI: 81.0 - 83.5); Irkutsk - 87.6% (95% CI: 87.6-88.9); Nizhny Novgorod - 86.5% (85.3-87.6); Kaliningrad - 74.2% (95% CI: 72.8 - 75.6); and the Republic of Crimea - 74.8% (95% CI: 73.4-76.1). In some cases, seropositivity did not reach 60%, namely: among individuals aged ≥60 in the Kaliningrad Region and the Republic of Crimea; and among individuals aged ≥70 in the Amur and Nizhny Novgorod Regions. Most volunteers had serum IgG Abs to diphtheria toxin at concentrations of 0.1–1.0 IU/ml, regardless of age, region, or vaccine type. Conclusion. The level of collective immunity mandated by current Russian documents (95% in children, 90% in adults) was practically not achieved in any region or age group (except children aged 1–5 years in the Irkutsk and Nizhny Novgorod Regions). In all regions, the least protected group were individuals aged 60 and older, among whom the seronegative value reached 30–45%.
