Introduction. The coronavirus disease (COVID-19) pandemic was announced by WHO in February 2020. In the Khabarovsk Krai, the first three cases of the disease were diagnosed on March 19, 2020, these cases were imported from Argentina (transit through Italy). The epidemic process of COVID-19 in the Khabarovsk Krai is characterized by a slow increase in the incidence. During the period of time when the SARS-CoV-2 seroprevalence study was conducted the incidence rates varied from 35.9 to 39.1 per 100 thousand population. Within the next 5 weeks the incidence continued to increase, the maximum level was 67.3 per 100 thousand population. A statistically significant decrease in the incidence is noted in the first decade of August. The study of the SARS-CoV-2 seroprevalence among residents of the region was carried out from June 9 to June 21, 2020 during the period of increasing intensity of the epidemic process of COVID-19 infection.Aim. To determine the level and structure of herd immunity to SARS-CoV-2 virus among the population of the Khabarovsk Krai during the period of intensive spread of COVID-19.Materials and methods. The study was conducted as a part of the first stage of a large-scale Rospotrebnadzor project to assess the herd immunity to SARS-CoV-2 virus among the population of the Russian Federation, taking into consideration the protocol recommended by WHO. The selection of volunteers for the study was carried out by the method of questionnaires and randomization by random sampling. The results of a survey of 2675 individuals were included into analysis. The number of volunteers in all age groups was similar.Results. The results of the study showed that the herd immunity to SARS-CoV-2 in the total population of the Khabarovsk Krai was 19.6%. The maximum level of herd immunity was observed in children 14–17 years old (34.4%), children 7–13 years old (24.8%), and people over 70 years (22.6%). The highest level of seropositivity, except for the children and the elderly, was found among educational workers (26.7%). The lowest level of seropositivity was found in the military (8.7%) and the unemployed (8.3%). There were no statistically significant differences in the level of seroprevalence between men and women.Conclusions. The results of the seroepidemiological study demonstrated that in the Khabarovsk Krai, the presence of the contacts with COVID-19 patients is associated with the 1.4-fold increase in the likelihood of the seroconversion. Antibodies were detected in 58.9% of the past COVID-19 cases. In individuals with the previous positive PCR test result, antibodies were detected in 50% of cases. A high rate of asymptomatic infection, up to 93.7%, was observed among seropositive volunteers.

Introduction: Supporting health and wellbeing of indigenous small-numbered peoples of the North is one of the priorities of the regional policy in the Khabarovsk Krai. The centuries-long adaptation of the population to local conditions has created a unique system of the traditional use of natural resources and the most efficient forms and types of households. Despite all globalization processes, fishing, hunting and gathering remain essential elements of the lifestyle of northern indigenous peoples. Against the natural background, specific features of their behavior and nutrition create optimal conditions for helminth life cycles and intense transmission of endemic helminth infections. Objective: To assess effects of the traditional lifestyle of the indigenous population of the Khabarovsk Krai as a factor responsible for the spread of larval helminthiasis and endemic trematode infections. Materials and methods: In 2010–2020, questionnaire-based surveys were conducted and feces samples were collected from Nanai people in the villages of Dada, Sikachi-Alyan, Sinda, and Naikhin and from Udege people in the villages of Gvasyugi and Arsenyevo during expeditions. Results: Endemic trematode eggs were detected in stool samples from all the villages. Clonorchis sinensis eggs were detected in the samples from Dada, Sinda, and Sikachi-Alyan, while Nanophyetus salmincola schikhobalowi eggs were found in the dwellers of Arsenyevo and Gvasyugi. Metagonimus spp. eggs were also detected in isolated cases. The results of sero-epidemiological survey indicate a high frequency of contacts with Toxocara roundworms in all areas and with tapeworms of the Echinococcus type in the traditional villages located in forest areas. Conclusion: Original lifestyle and dietary habits of indigenous peoples in the Khabarovsk Krai pose a high risk of trematode infections (clonorchiasis, nanophietiasis, metagonimiasis) and larval helminthiasis (echinococcosis, toxocarosis). In combination with poor awareness of the population of appropriate preventive measures, this risk contributes to high incidence and prevalence rates of helminthiases in all surveyed national villages.

Aim. To analyze current epidemiological and epizootological situation on cystic (hydatidiform) echinococcosis in constituent entities of the Far Eastern Federal District (FEFD) of the Russian Federation. Materials and methods. Data of the administrations of the Federal service for surveillance on consumers rights protection and human wellbeing as well as data of the FBIH «Center of hygiene and epidemiology» located in different constituent territories of the FEFD during 2013-2017 was used. A review of scientific papers concerning the topic of the current article was performed. Results. Mainly sporadic cases of the disease were registered in 7 out of 9 constituent entities of the FEFD during the 2013-2017. The Jewish Autonomous district and Kamchatka region were free of the echinococcosis during the 5-year observation period. Echinococcosis cases were registered annually in the Chukotka Autonomous district, Republic Sakha (Yakutia) and Primorsky region. Herewith, the incidence rates in Chukotka Autonomous district and Republic Sakha (Yakutia) notably exceeded the national average. No fatal outcomes due to cystic echinococcosis in the FEFD were registered. Conclusion. Implementation of immunoepidemiological surveillance of the population of different age groups and professions is recommended on the constituent entities with registered cases of cystic echinococcosis.