ABSTRACT
The aim was to present the experience of using mobile laboratory for monitoring and diagnostics (MLMD) during the epizootiological monitoring of the northern provinces of Vietnam. MLMD was transferred by Federal Service for Surveillance in the Sphere of Consumers Rights Protection and Human Welfare to the Socialist Republic of Vietnam as part of implementation of cooperation programs on combating infectious diseases. The use of MLMD made it possible to obtain new information on the circulation of pathogens of natural-focal infectious diseases on the territory of Vietnam. It also provided the necessary conditions for conducting research using methods of express diagnostics, bacteriological analysis, performing a full cycle of work – from the receipt of samples to the disinfection and destruction of infected material in compliance with the requirements of biological safety in the field. The effectiveness of using mobile laboratories in response to the emergencies of sanitary and epidemiological nature, both to strengthen stationary laboratory bases and to organize diagnostic studies in remote regions, has been shown. The use of MLMD for the diagnosis of COVID-19 has been an effective component of countering the new coronavirus infection in Vietnam and significantly increased the volume of testing in the country. © 2022 Russian Research Anti-Plague Institute. All rights reserved.
ABSTRACT
Emergence of various genovariants of the SARS-CoV-2 virus, which are characterized by a higher ability to spread and a more severe clinical manifestations compared to the initial variants, require molecular-genetic monitoring of strains circulating in the Russian Federation. The aim of the work was to identify the VOC SARS-CoV-2 genovariants in the territory of the Republics of Bashkortostan, Tatarstan, Udmurtia, and Samara, Penza, Saratov, Ulyanovsk, and Orenburg Regions. Materials and methods. The identification of genovariants and the determination of the type of mutations was carried out by the Sanger fragment sequencing method. Results and discussion. The study examined 298 samples of clinical material obtained from the Centers for Hygiene and Epidemiology in the Republics of Bashkortostan, Tatarstan, Udmurtia, Samara, Penza, Saratov, Ulyanovsk, and Orenburg Regions. In 17 % of cases, the variability of the SARS-CoV-2 virus was observed for one or more markers: in three samples, a new coronavirus of the B. 1.1.7 line (“British”) was detected;in a number of cases, only one mutation was detected in the virus found in samples - deletion Y144 or substitution D138Y, E484K, N501Y, and very rarely two mutations - deletion Y144 and substitution E484K. The presence of the L141-G142-V143 deletion localized in the recurrent deletion region RDR2 of the S-gene was shown in 10 % of the cases. The data obtained indicate the heterogeneity in macroorganism of the population of the new coronavirus with the deletion L141-G142-V143, which leads to a change in the antigenic structure of the virus, which probably allows the virus to evade the immune response. © 2021 Russian Research Anti-Plague Institute. All rights reserved.
ABSTRACT
The global community is experiencing one of the largest infectious disease outbreaks in the 21st century. In the Saratov Region, the first case of new coronavirus infection was confirmed on March 19, 2020.The maximum increase in cases was noted between May 15 and June 30, during that time the total number of infected people in the region increased from 1526 to 6444. Since July 2020, a stable incidence level of new coronavirus infection has been observed in the Saratov Region, without a steady decline. The aim of the study was to assess the status of population immunity to the SARS-CoV-2 virus among residents of Saratov and the Saratov Region under the COVID-19 epidemic. Materials and methods. In the period from June 23 to July 26, 2020, a serological study of blood samples from 3372 volunteers of different age groups was conducted. The content of antibodies to SARS-CoV-2 was determined by ELISA using a set of reagents “ELISA anti-SARS-CoV-2 IgG” produced by the State Scientific Center of Applied Microbiology and Biotechnology of the Rospotrebnadzor (Russia). Results and discussion. In general, the incidence of COVID-19 in the Saratov Region is taking place against the background of moderate seroprevalence to the SARS-CoV-2 virus, accompanied by a high incidence of non-apparent (asymptomatic) forms of the infectious process. The absence of clinical symptoms of the disease, in the context of the limited use of methods for determining the RNA of the SARS-CoV-2 virus in PCR (11 % of the region’s population) makes it difficult to assess the real spread of the virus in the population and to establish the timing of the formation of persistent herd immunity. A low rate of antibody response among individuals with a positive result of PCR analysis, as well as among volunteers who had an infection in May, June 2020, indicates a weak formation of the immune response, or the prevalence of individuals reacting mainly by activating the cellular link of the immune system in the population. The obtained results, although they need to be explained in a number of respects, can be applied to the organization of preventive measures, including vaccination, in the region. © 2020 Russian Research Anti-Plague Institute. All rights reserved.
ABSTRACT
The review presents the analysis of the data on the spread of COVID-19 around the world and in Russia available as of June 15, 2020. Dynamics and geographical dissemination of COVID-19 in the Russian Federation is considered. The structure of incidence by gender and age is presented. Assessment of the key epidemiological parameters (morbidity rates and lethality) is provided. The effectiveness of the response measures conducted to control COVID-19 is discussed. © 2020 Russian Research Anti-Plague Institute. All rights reserved.
ABSTRACT
Objective: to study the evolution of SARS-CoV-2 virus in the process of adapting to human organism during the current pandemic. Materials and methods. Database (GISAID) on nucleotide sequences of SARS-CoV-2 virus genome, obtained from clinical samples during the period of late December, 2019–July, 2020. Phylogenetic tree diagram construction was carried out applying BioNumerics v.7.6 software using Maximum parsimony algorithm. Results and discussion. The most substantial change in the genomes of SARS-CoV-2 virus are associated one-time mutations in ORF1b (P314L) and S (D614G) genes, as a result of which the overwhelming majority of identified isolates of this virus have the stated pair of substitutions to date. Many researches link the substitution in S (D614G) gene to the decreased pathogenicity in the strains that contain it, which may be also explained by enhanced methodology of patient treatment in the course of pandemic. The effect of the mutation in ORF1b (P314L) gene has not yet been investigated. P314L and D614G mutations are closely related and only their combined presence in the genome favored the dissemination of the genovariants of SARS-CoV-2 virus. Analysis of congregated epidemiological data testifies to the fact that the spread of new genovariants may be associated with biological properties facilitating human-to-human transmission. Thereat, associated decrease in lethality may reflect not only advancements in methods of treatment, but possible attenuation of virulent properties. Thus, observed growth in dissemination potential against the background of decrease in virulence is, probably, one of the forms of adaptation of new coronavirus to human population and, apparently, will remain in the future as the integration of SARS-CoV-2 virus into the structure of seasonal ARVI agents. © 2020 Russian Research Anti-Plague Institute. All rights reserved.
ABSTRACT
The review analyses the information on the epidemiological situation on COVID-19 around the world. Presented is the assessment of the major epidemiological parameters (basic reproductive rate, lethality, incubation period, and serial interval). Demonstrated is the share of severe cases among different age groups and the general structure of incidence by the severity of clinical course. The paper provides the classification of response models internationally depending upon the complex of measures undertaken at different stages of epidemic process. Reviewed are the key response actions to control the COVID-19 transmission in different countries of the world and the Russian Federation and given is the assessment of their effectiveness. © 2020 Russian Research Anti-Plague Institute. All rights reserved.