We analyzed the epidemiological situations on influenza and acute respiratory viral infections during the 2015–2016, 2016–2017 and 2017–2018 epidemic seasons in the Republic of Sakha (Yakutia). The 2015–2016 and 2016–2017 epidemic seasons differed from the previous ones by a rather high intensity of the epidemic process, moderate duration of the epidemic awareness with a two-wave pattern of the course, high morbidity of the population at the epidemic peak and the absence of the disease’s severe forms in those vaccinated against influenza. During the 2015–2016 epidemic season, the influenza A (H1N1) virus was the dominant pathogen in Yakutia. During the 2016–2017 epidemic season, the first morbidity awareness was caused by the influenza A (H3N2) virus, the second morbidity awareness was caused by the influenza B virus. In contrast to previous two seasons the 2017–2018 epidemic season is characterized by lower intensity, a significant morbidity decrease of influenza and acute respiratory viral infections in different age groups of the population and a low level of influenza viruses' circulation. Influenza A (H3N2) virus dominated and joined influenza B virus circulation was registered subsequently during the 2017–2018 epidemic season.

Проведен ретроспективный анализ проявлений эпидемического процесса энтеровирусной инфекции в Хабаровском крае в предшествующий наводнению семилетний период. Показано наличие предпосылок возможного осложнения эпидемиологической обстановки в период чрезвычайной гидрологической ситуации 2013 г. В крае из года в год сохраняется стабильно неблагополучная ситуация по заболеваемости энтеровирусными инфекциями, наблюдаемая при благоприятных климатических условиях -высоких температурах воздуха и воды поверхностных водоемов, высокой влажности воздуха. Поддержанию эпидемического процесса в течение всего года способствуют «здоровое» вирусоносительство и обширное распространение энтеровирусов в водных объектах внешней среды. Отмечена широкая циркуляция различных генотипов энтеровирусов, в том числе имеющих высокую степень генетического сходства со штаммами, зарегистрированными на сопредельной территории Китайской Народной Республики.Ключевые слова: энтеровирусная инфекция, Хабаровский край, эпидемический процесс, заболеваемость, штаммы энтеровирусов.Carried out has been retrospective analysis of epidemiological process manifestations as regards enteroviral infection in the Khabarovsk Region over the period of 7 years, prior to rainfall floods in 2013. Revealed is the possibility of aggravation of epidemiological situation during hydrological emergency situation. The premises are as follows: persistent due to specific climate conditions prevalent in the Khabarovsk Territory (high air and surface water temperatures, and high humidity rates) unfavorable epidemiological situation on enteroviral infections, virus-carriage in "healthy" people and extensive dissemination of enteroviruses in the water bodies of ambient environment. Moreover, widespread circulation of different enterovirus genotypes, including the isolates with high genetic similarity to the strains identified earlier in the adjoining People's Republic of China, takes place.

Aim. To reveal peculiarities of acute respiratory viral infections (ARVI) incidence among population of the Far Eastern Federal District depending on viral etiology during two epidemic seasons (2017-2018 and 2018-2019). Materials and methods. Method of epidemiological analysis by means of ARVI incidence with weekly epidemic thresholds as utilized. Laboratory diagnosis of respiratory viruses was carried out by applying RT-PCR method and test-kits of the Central Research Institute of Epidemiology. In order to determine relations between ARVI incidence and viral etiological structure of ARVI correlation and regression analysis was performed. Results. Identical epidemical tendencies with differences in ARVI incidence intensity were registered in the evaluated constituent entities of the Russian Far East. Utmost intensity of epidemic process was revealed in the Republic Sakha (Yakutia) and Sakhalin Oblast. In the south regions (Khabarovsk and Primorsky Krai, Amur Oblast) ARVI incidence, occasionally excessing epidemic threshold was lower. Territorial and time irregularity is peculiar for etiology of infections in the Russian Far East. During the epidemic season of 2017-2018 statistically significant prevalence was determined for the influenza virus B in Primorsky and Khabarovsk Krai, influenza virus A(H3N2) ‒ in the Sakhalin Oblast, respiratory syncytial virus ‒ in the Republic Sakha (Yakutia), rhinoviruses were dominant in the Amur Oblast. During the 2018-2019 epidemic season influenza virus A(H1N1)pdm09 was mostly prevalent in most of the constituent entities of the Russian Far East. Compared to the other regions of the Far Eastern Federal District in the Amur Oblast were revealed differences in circulation of respiratory viruses predominantly of non-influenza origin during two observed epidemic seasons. Conclusion. Constant evaluation of ARVI epidemics under the conditions of constantly changing landscape of circulating viruses in a particular region can be useful for determination of strategies and tactics of epidemiological response.

Considerable aggravation of sanitary-hygienic situation forming the basis for occurrence of mass infectious disease outbreaks is observed when immense territories are water logged, and water supply systems are destructed. Therewith in order to provide control over the spread of acute enteric water-borne infections in the Jewish Autonomous Region investigated was the morbidity both in the last decade and after the flood period in 2013. The system of organizational and preventive actions included inspection of water intake constructions, zones of sanitary protection of water fences; laboratory control over the drinking water quality; organization of the homesteads patrolling for early detection of infectious diseases; monitoring of the infectious and parasitic diseases incidence rate; management of the vaccine prophylaxis; inspection of solid household waste storage sites and other epidemically significant objects in the flooded area; determination of necessary disinfectant quantity; provision of the population with information concerning implementation of the post-flood prophylactic measures. The actions undertaken permitted to get the epidemic situation on acute enteric infections including the water-dependent ones under control.