Hemorrhagic fever with renal syndrome (HFRS) is registered annually among residents of Khabarovsk city, Russia. The aim of the study was to conduct a genetic analysis of hantaviruses, the causative agents of HFRS, in residents of Khabarovsk city and in Norway rats (Rattus norvegicus), a natural reservoir of Seoul virus (SEOV), captured in Khabarovsk and its suburbs. Materials and methods. Blood sera samples from 75 patients with HFRS, collected in 2016–2023 (blood plasma – in 2017) and samples from 1468 Norway rats, captured during 2011–2023, were investigated. Results and discussion. We have demonstrated the presence of the Seoul virus (SEOV) in samples of Norway rats from the city of Khabarovsk and the suburban settlement Priamursky, Jewish Autonomous Region; 2 RNA isolates of the SEOV virus, 33 isolates of the Hantaan virus (HTNV), 9 isolates of the Amur virus (AMRV) – in patients with HFRS from Khabarovsk. Phylogenetic analysis of partial S and L segments of the genome has revealed that three RNA isolates of SEOV from Norway rats and two isolates from HFRS patients are most closely related (99 % homology) to strains from China and are different from the variant of SEOV from Vladivostok. It is assumed that the urban focus of the Seoul virus in Khabarovsk and its environs was formed as a result of the importation of virus carriers from China, where this variant of the virus is widespread. The data obtained indicate that the incidence of HFRS in residents of Khabarovsk, caused by infection with the HTNV and AMRV viruses, is associated with visits to various rural areas of the Far East.

The MTIR-SCP reactor is a research reactor with a light-water coolant having a fast neutron spectrum in nominal operation. None of the existing or projected reactors has a set of these features, therefore, special attention should be paid to the choice of the design of control rods and their location. The article considers various designs of control rods characteristic of the VVER-SCP power reactor currently under development, as well as existing research reactors with a liquid metal coolant having a fast neutron spectrum, taking into account the features of the MTIR-SCP: a seven-element control rod assembly design, as well as a ring-type absorbing element. Efficiency calculations are carried out for each of the structures under consideration and it was determined that the design of a control rod with an annular type of absorbing element has the highest specific efficiency. This design is chosen as the main one for the MTIR- SCP reactor. Criteria are proposed and optimization of the placement of control rods in the reactor core is carried out in order to reduce the uncertainty of obtaining neutron-physical characteristics in the central autonomous loop channel and increase the flow density in it. When optimizing the placement of control rods in the research reactor, their influence on the main neutron-physical characteristics, and especially on their distribution during operation under nominal conditions, is taken into account. Emergency protection and compensating rods that compensate for temperature and density effects when the reactor reaches the nominal power level have been removed, therefore their effect on the neutron-physical characteristics of the reactor and the loop channel during operation at power is not significant, and the compensating rods are located in the core and are removed as the fuel burns out, therefore their effect on the spatial The distribution of neutron-physical characteristics will be significant. To reduce this effect, burnout compensators and automatic regulators are proposed to be moved outside the core into the reflector. For various reactor conditions, the efficiency of the control and protection system was evaluated. It is shown that in various states, the control rods transfer the reactor to the required level of subcriticality, in accordance with NP-009-17.

The mtDNA control region variability of Microtus rossiaemeridionalis (Rodentia, Arvicolini) from two invasive populations of the Russian Far East was studied. The results demonstrated a lower genetic diversity in the East European vole population from Sovetskaya Gavan than in the population from the city of Khabarovsk. Wright’s F statistic did not reveal any heterogeneity in the samples from these populations. It was suggested that the discovered haplotypes belong to the EU subclade of the European lineage.

The sibling vole, Microtus rossiaemeridionalis, is a North Eurasian rodent that undergoes range expansion via casual introductions by humans. The documented cases of human-mediated spread of M. rossiaemeridionalis provide an opportunity to explore phenotypic consequences associated with the invasion events. We present an analysis of dental variability in two recently discovered invasive populations of M. rossiaemeridionalis in northern Asia (Surgut and Khabarovsk) and summarize the data on conspecifics within and outside the core range in order to uncover common and specific patterns of dental variation in the disjunctive invasive populations, and to consider the potential evolutionary significance of the phenotypic effects from neontological and paleontological standpoints. The analysis of morphotype dental patterns and inspection for rare traits suggest that the existence of invasive populations under conditions of isolation leads to a release of hidden phenotypic variation, which could be inferred from sharp increases in frequencies of reserve morphotypes and/or rare dental traits, and also from the presence of abnormalities. An atavistic anomaly of the third upper molars revealed in one individual in a fragmented habitat in Surgut recapitulates some features of the prismatic arrangement and occlusal pattern of extinct Mimomys-like arvicolines. All variants of released phenotypic variation in the invasive populations of M. rossiaemeridionalis under conditions of isolation could be interpreted as de-specialization of dentition. Such de-specialization appears to be maladaptive for a herbivore, though it might favor a transition to a more generalized diet and enhance the success during the transport, colonization, and establishment stages of the invasion.

The article presents data on zoological and entomological monitoring and results of laboratory tests on presence of tick-borne diseases of non-sated and sated ixodic ticks that confirm existence of combined tick-borne diseases foci on the territory of Khabarovsk region. The results showed high number of transmitting carriers. In these circumstances, the levels of carrier activity as well as tick contamination with bacterial infectious agents in 2016 did not exceed reported levels during previous years.

Carried out were epizootiological studies of the flooded areas of the Amur Region, the Khabarovsk territory, and the Jewish autonomous region in order to investigate the situation on tularemia in view of the river floods in August-September, 2013. Involved were specialized anti-epidemic teams from Irkutsk Research Anti-Plague Institute for works at the site of emergency. Therewith, analysis of the data of the epizootiological examination of the territories obtained in cooperation with specialists from the Rospotrebnadzor local Centers of Hygiene and Epidemiology, and results of laboratory investigations with application of bacteriological, immu­no­bio­logical and molecular-genetic methods indicated insignificant epizootic and epidemic activity of the natural tularemia foci. Given is the conclusion on epizootiological-epidemiological condition for tularemia in the flooded areas of the Amur River region and a short-term epizootiological forecast for 2013-2014, as well as recommendations concerning stabilization and improvement of epidemiological conditions in the region.

Complex analysis of the data concerning epidemiological situation on HFRS in the Khabarovsk Territory and the Jewish Autonomous Region for the past decade (2003-2012) previous to high water in 2013 and results of operative epidemiological inspection of the flooding area and the adjoining territory where a high index of laboratory evidences of the virus presence in the main carriers was revealed, outlines high probability of the epidemiological condition complications in view of the infection in the post-flooding period in 2013-2014 in the both entities. Therewith on the basis of the unfavorable prognosis for the epidemiological situation development a Plan of organizational, preventive and anti-epidemic measures directed to minimization of risks related to aggravation of epidemiological situation on hemorrhagic fever with renal syndrome has been developed and is being implemented.

Widespread epizootiological investigations were performed to estimate the influence of the Amur River flood on the epizootic activity of tularemia in small rodent populations within natural and anthropourgic foci. Determined were the numbers of the rodent-carriers and epizootic activity of tularemia infection in the forest type, lowland, flood-swamped as well as anthropourgic foci. The capture and enumeration of the rodents was conducted using Gero rat traps. Tested were water and silt samples, rodent nests, pellets and excrements of carnivorous mammals. Blood sera of healthy persons living within the focal territory were examined to reveal the immune-competent cohort. Collected materials were analyzed using bacteriological, genetic diagnostic and serological methods. Extremely high numbers of the carriers were registered in the lowland meadow-field and anthropourgic foci adjacent to the flooded areas. The signs of tularemia epizootic process were observed in the meadow-field and flood-swamped foci. Failed to reveal during the period of high water were the epizooties in the forest foci.

In this study, we report the first case of observation of the East European vole Microtus rossiaemeridionalis Ognev, 1924 in the south of the Russian Far East, Khabarovsk krai, in urbanized biotopes in the vicinity of the city of Sovetskaya Gavan and two adjacent rural settlements. The species was identified by karyological characteristics—2n = 54, NF = 56, C-banding—and morphological characteristics—body, cranium, baculum, and spermatozoa.

The authors present the material on the species composition and the number of small rodents in four biotopes of the region explored from February to November 2009-2010. A census was carried out using the conventional method of trap-lines. Special attention is paid to background (numerically dominant) species which are very dangerous in the spread of such diseases as Apodemus agrarius, Microtus maximoviczii and others. The study presents a comparison with the data published in the 1980s-90s. The most significant difference from V. I. Volkov's and his coauthors' publications which dealt exclusively with Microtus fortis, is that in this article the major role is assigned to the dominant M. maximoviczii. M. fortis, which in the 1980s-90s was kind of background, but in our case was met periodically and turned out to be rare. In comparison with the previous data, Apodemus peninsulae has increased its number.

It was shown by agglutination, gel diffusion, and immunoelectrophoretic tests that an antigen common toMycobacterium bovis (BCG) and some malignant and normal cells of rat tissues exists. By absorption of immune sera and the agglutination test the specificity of this antigen was demonstrated for BCG cells and cells of primary induced tumors of rat muscle tissue. This antigen has electrophoretic mobility in the β-globulin zone.