Haemorrhagic fever with renal syndrome (HFRS) is the most prevalent zoonotic disease in Russia. It is caused by several hantavirus species hosted by small rodents. We describe spatial and temporal patterns of HFRS incidence in the Russian Federation, and the geographic distribution of prevalent hantavirus species: Puumala (PUUV) and Dobrava (DOBV). Partial sequencing of nucleocapsid and glycoprotein genes of 117 PUUV strains and 78 DOBV strains revealed several distinct genetic subgroups. The RNA of Volga PUUV subgroup was detected in patients with HFRS and bank voles Myodes glareolus in the Volga Federal District, where the highest HFRS incidence rate has been registered yearly. The RNA of Siberian PUUV subgroup was found in M. glareolus in the trans-Ural Tyumen and Omsk Provinces, where human HFRS cases have been rare. During an HFRS outbreak in 2007 in the Central Federal District, when more than 1000 patients were affected, specific subgroups of DOBV were discovered in patients and rodents, mainly in the striped field mouse Apodemus agrarius. DOBV strains might have 8–9% of nucleotide difference although they were collected at places separated by 30–100 km. The RNA of a unique DOBV subgroup was discovered in the southern semi-desert Astrakhan Province, mainly in A. agrarius and tamarisk jird Meriones tamariscinus. No human HFRS cases were diagnosed in this province. Russian PUUV and DOBV strains have no close homologues among European strains. Our DOBV strains might be genetically grouped together with Central European DOBV strains isolated from A. agrarius, but not from Apodemus flavicollis. The Volga PUUV subgroup is to some extent similar to Baltic PUUV strain, and Finnish PUUV strains resemble the strains from the Siberian PUUV subgroup. Thus, PCRbased monitoring and typing provided the opportunity to delineate and expand the area of hantaviruses in Russia and to identify their new genetic variants.

Relevance. They did not learn completely the information of the distribution of morbidity by territory and population sex-age groups in the context of a pandemic of a new coronavirus infection (COVID-19).Aims. It is necessary to study COVID-19 distribution features among the population of the central Orenburg region administrative districts in June–December 2020.Materials & Methods. We analyzed the results of the study of the polymerase chain reaction (PCR) COVID-19 of the population of the Central Orenburg region for June-December 2020 (72 484 nasopharyngeal smears from 13 districts of the region). The presence of SARS-CoV2 RNA was detected by real-time reverse transcription PCR. The significance of differences in indicators was assessed using the paired Pearson test (p≤0.05; EPI-INFO, version 7.2.4; CDC).Results. The share of positive findings was 15,5% of the studied material from 12,5% of the population. Registration of COVID 19 cases in the Central Orenburg region began in June 2020. They revealed a significant correlation between the dynamics of the districts population morbidity and the dynamics of examined persons number. The study of morbidity dynamics showed a significant growth with the registration of maximum values in October with a decrease in disease cases in December by 2 times. They identified the highest morbidity rates territories (Aleksandrovsky, Akbulaksky, Sharlyksky, Tyulgansky, Perevolotsky, Sol-Iletsky, Saraktashsky, Belyaevsky dist at the average regional level 2204,9 0 /0000 ). The distribution of cases by sex revealed the predominance of women disease cases (56,8%) over the men proportion (43,2%). Women dominated among adults under 65 years of age, while men dominated in the children's and over 65 years of age groups. However, the prevalence analysis for the given period showed the women dominance in all age groups in all the studied territories. They can conclude that there is a great women commitment to medical care. It was not possible to identify significant correlations between the morbidity level and the districts remoteness from Orenburg. It is likely that at modern communication speeds distances of 250–300 km are not a significant barrier to a new infection with a dominant airborne transmission pathway spread.Conclusions. The study showed a mobidity significant growth for 2020. 8 of 13 territories under study became those of increased risk of morbidity. Cases of the disease ratio among men and women responds to the men and women ratio among the population. The age group of 0-18 was least affected. The analysis showed a morbidity reliable growth with increasing age of patients of both sexes and revealed a large inferiority of the female population.

The study of a new coronavirus infection (COVID-19) in children is relevant and of interest for practical health care.Purpose: to identify the clinical and laboratory features of COVID-19 in the context of the six-month dynamics of the pandemic in children of the Orenburg region and to formulate recommendations for optimizing the diagnosis of this disease.Materials and methods. A retrospective analysis of 2661 results of detecting SARS-CoV-2 RNA (including 170 children) was carried out on the basis of the microbiological laboratory of the Orenburg State Medical University. Age and sex, structure of preliminary diagnoses, main clinical manifestations, frequency of testing and dynamics of the PCR threshold cycle in September 2020 and January 2021 were assessed.Results. The proportion of children examined in the Orenburg region from September 2020 to January 2021 increased from 4.6 ± 0.6% to 8.1 ± 0.7%. At the same time, the number of PCR + results also significantly increased from 5.0 ± 2.8% to 8.2 ± 2.6% (χ2 = 54.81; p = 0). The average age of children was 9—10 years old. The main reason for referral was pre-hospitalization screening not related to COVID-19. The proportion of PCR + results in this cohort was significantly lower in children than in adults. Among the clinically manifested forms in adults, the leading diagnosis was «pneumonia», and in children «ARVI». In childhood, a predominantly asymptomatic course of the disease was recorded. In children, unlike adults, PCR Ct values did not correlate with the severity and duration of the clinical manifestations of COVID-19.Conclusion. Due to the low diagnostic value of symptoms in children, it is more expedient to focus on epidemiological data and data from the results of laboratory examination methods. When interpreting the results of PCR diagnostics of COVID-19 for prognostic purposes, it is important to take into account the patient's age.

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