Olga Ilyinichna Kanaeva

Introduction. Enteroviruses (genus Enterovirus, family Picornaviridae) are one of the common causes of infectious diseases with neurological and dermatological manifestations in children. Surveillance of these viruses is carried out as part of the program Epidemiological surveillance and prevention of enterovirus (non-polio) infection for 2023–2027. Objective. To study the type diversity of non-polio enteroviruses (NPEVs) isolated from clinical specimens and wastewater samples collected in Saint Petersburg and the Leningrad Region, and to perform molecular epidemiological characterization of Coxsackievirus B5 isolates. Materials and methods. Stool samples were collected from resident children with clinical symptoms, healthy migrants under 5 years of age; wastewater samples were also included in the study. Enterovirus isolation was performed by inoculation of specimens onto RD, HEp-2, and L20B cell cultures. Molecular genetic methods included PCR, Sanger sequencing, nucleotide sequence analysis and phylogenetic analysis using the R programming language. Estimation of tMRCA and construction of nucleotide identity heatmaps were performed using TreeTime and SDTv 1.3 software, respectively. Results. A total of 25 NPEV types were identified. At the species level, Enterovirus betacoxsackie predominated – 53/71 (74.6%; 95% CI: 62.9–84.2%), followed by Enterovirus alphacoxsackie – 17/71 (23.9%; 95% CI: 14.6–35.5%), and Enterovirus coxsackiepol – 1/71 (1.4%; 95% CI: 0.04–7.6%). In Saint Petersburg and the Leningrad Region, viruses belonging to Enterovirus betacoxsackie were most frequently detected: Coxsackievirus B5 (12.7%), ECHO 11 (11.3%), ECHO 13 (8.5%), ECHO 14 (8.5%), and ECHO 6 (8.5%). A notable prevalence of ECHO 25 (5.6%) and ECHO 29 (5.6%) was also observed. A comprehensive analysis of the phylogenetic tree, nucleotide identity heatmap, and tMRCA estimates showed that the CVB5 strains isolated from resident children in 2018 and from migrant children in 2021 belonged to two distinct genetic lineages, indicating multiple independent introductions of the virus into the Russian Federation. Conclusion. The frequent detection of Enterovirus betacoxsackie in the studied collection of isolates and the identification of two genetic lineages of Coxsackievirus B5 confirm the complexity of its epidemiological dynamics and highlight the necessity of continuous surveillance for the timely detection of new genetic variants.

Enteric viruses are a major cause of waterborne infections due to their high environmental stability and extremely low infectious dose. Current molecular diagnostic methods, while accurate, often depend on thermal cycling and centralized laboratory facilities, limiting their applicability in decentralized or resource-limited settings. In this study, we developed an isothermal biosensor based on a split deoxyribozyme that reconstitutes its catalytic core upon hybridization with a conserved sequence of enteroviral RNA. This activation leads to site-specific cleavage of a fluorogenic substrate, producing a quantifiable fluorescent signal. The system was experimentally validated using both synthetic enteroviral RNA and RNA extracted from environmental water samples. To enhance detection sensitivity, the DNAzyme-based assay was coupled with isothermal RNA amplification. The results demonstrate high selectivity and compatibility with real-world samples, supporting the sensor’s utility for field-deployable viral RNA detection. Overall, this study highlights the potential of the DNAzyme-based platform as a portable, sequence-specific, and amplification-assisted diagnostic tool for environmental surveillance of enteric viruses.

Enteroviruses (EV) are important pathogens causing human disease with various clinical manifestations. To date, treatment of enteroviral infections is mainly supportive since no vaccination or antiviral drugs are approved for their prevention or treatment. Here, we describe the antiviral properties and mechanisms of action of leucoverdazyls—novel heterocyclic compounds with antioxidant potential. The lead compound, 1a, demonstrated low cytotoxicity along with high antioxidant and virus-inhibiting activity. A viral strain resistant to 1a was selected, and the development of resistance was shown to be accompanied by mutation of virus-specific non-structural protein 2C. This resistant virus had lower fitness when grown in cell culture. Taken together, our results demonstrate high antiviral potential of leucoverdazyls as novel inhibitors of enterovirus replication and support previous evidence of an important role of 2C proteins in EV replication.

Enteroviruses (EV) are important pathogens causing human disease with various clinical manifestations. To date, treatment of enteroviral infections is mainly supportive since no vaccination or antiviral drugs are approved for their prevention or treatment. Here, we describe the antiviral properties and mechanisms of action of leucoverdazyls - novel heterocyclic compounds with antioxidant potential. The lead compound, 1a, demonstrated low cytotoxicity along with high antioxidant and virus-inhibiting activity. A viral strain resistant to 1a was selected, and the development of resistance was shown to be accompanied by mutation of virus-specific non-structural protein 2C. This resistant virus had lower fitness when grown in cell culture. Taken together, our results demonstrate high antiviral potential of leucoverdazyls as novel inhibitors of enterovirus replication and support previous evidence of an important role of 2C proteins in EV replication.

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Appearing in Wuhan (China) and quickly spreading across the globe, the novel coronavirus infection quickly became a significant threat to global health. The year 2021 was characterized by both increases and decreases in COVID-19 incidence, and Russia was no exception. In this work, we describe regional features in the Northwestern federal district (FD) of Russia of the pandemic in 2021 based on Rospotrebnadzor statistics and data from SARS-CoV-2 genetic monitoring provided by the Saint Petersburg Pasteur Institute as a part of epidemiological surveillance. The epidemiological situation in the studied region was complicated by the presence of the megacity Saint Petersburg, featuring a high population density and its status as an international transport hub. COVID-19 incidence in the Northwestern FD fluctuated throughout the year, with two characteristic maxima in January and November. An analysis of fluctuations in the age structure, severity of morbidity, mortality rates, and the level of population vaccination in the region during the year is given. Assessment of epidemiological indicators was carried out in relation to changes in locally circulating genetic variants. It was seen that, during 2021, so-called variants of concern (VOC) circulated in the region (Alpha, Beta, Delta, Omicron), with Delta variant strains dominating from June to December. They successively replaced the variants of lines 20A and 20B circulating at the beginning of the year. An epidemiological feature of the northwestern region is the AT.1 variant, which was identified for the first time and later spread throughout the region and beyond its borders. Its share of the regional viral population reached 28.2% in May, and sporadic cases were observed until September. It has been shown that genetic variants of AT.1 lineages distributed in Russia and Northern Europe represent a single phylogenetic group at the base of the 20B branch on the global phylogenetic tree of SARS-CoV-2 strains. The progression of the COVID-19 pandemic occurred against the background of a vaccination campaign. The findings highlight the impact of vaccination on lowering severe COVID-19 case numbers and the mortality rate, despite ongoing changes in circulating SARS-CoV-2 genetic variants.

The COVID-19 pandemic, which began in Wuhan (Hubei, China), has been ongoing for about a year and a half. An unprecedented number of people around the world have been infected with SARS-CoV-2, the etiological agent of COVID-19. Despite the fact that the mortality rate for COVID-19 is relatively low, the total number of deaths has currently already reached more than three million and continues to increase due to high incidence. Since the beginning of the pandemic, a large number of sequences have been obtained and many genetic variants have been identified. Some of them bear significant mutations that affect biological properties of the virus. These genetic variants, currently Variants of Concern (VoC), include the so-called United Kingdom variant (20I/501Y), the Brazilian variant (20J/501Y.V3), and the South African variant (20H/501Y.V2). We describe here a novel SARS-CoV-2 variant with distinct spike protein mutations, first obtained at the end of January 2021 in northwest Russia. Therefore, it is necessary to pay attention to the dynamics of its spread among patients with COVID-19, as well as to study in detail its biological properties.

Background: Coxsackievirus A10 (CV-A10) is currently one of the most common etiological agents of enterovirus infection (EVI). Over the past decade, severe and fatal cases of CV-A10 infection have become more frequent while clinical manifestations of the disease are similar to those of Enterovirus A71 infection. The objective of our study was to characterize circulation of Coxsackievirus A10 in the Russian Federation in 2008–2019 and to study the phylogenetic relationships of strains isolated in Russia and Vietnam. Materials and methods: In 2008–2019, 220 CV-A10 strains were isolated from patients with various clinical manifestations of EVI and from sewage water samples taken in the Russian Federation and then studied using molecular genetic methods. In addition to that, we analyzed 26 CV-A10 strains isolated from patients with hand, foot, and mouth disease (HFMD) and acute flaccid paralysis in South Vietnam in 2018–2019. Results: We established a two-year periodicity of CV-A10 active circulation in Russia. In the structure of clinical forms of CV-A10 infection, herpetic angina prevailed (30.8 %), followed by minor illness (25.25 %), respiratory diseases (15.66 %), exanthema (14.65 %), gastrointestinal disorders (8.08 %), and asymptomatic infections (2.02 %). Symptoms of CNS damage (meningitis, meningoencephalitis) were observed in 3.53 % of cases. Most CV-A10 strains from Vietnam were isolated from patients with CNS affection of varying degrees of severity. During the study period, CV-A10 strains of genotypes C, E, and F3 circulated in the territory of the Russian Federation whereas the strains from South Vietnam were represented by genotypes F3 and F1. The studied strains showed a genetic relationship with those of CV-A10 circulating in different countries. Vietnamese and some Russian strains of the F3 genotype were genetically close to the strains isolated from severe cases. Conclusions: Molecular monitoring of CV-A10 circulation is an important component of the global epidemiological surveillance of EVI.

Aim: Analysis of the morbidity of vaccine-associated paralytic poliomyelitis and acute flaccid paralysis and the results of virological investigation of the patients on 14 territories of the Russian Federation in 1998-2017. Materials and methods: We investigated nearly 3000 stool samples from paralytic patients and contact persons. Isolation and identification of polioviruses were performed according to WHO recommendations with the help of cell lines RD and L20B. We conducted the sequencing of the genome fragments VP3-VP1, VP1-2A and full sequencing of genome region VP1 of 45 poliovirus strains. Results: From 1998 till 2017 1257 cases of acute flaccid paralysis were registered on 14 territories of Russia, 15 cases of which (1,2%) were classified as vaccine-associated paralytic poliomyelitis. From these patients 9 children were non vaccinated and 6 children received from one to four doses of oral poliomyelitis vaccine. The percentage of the detection of polioviruses from the patients and contact persons in different years was not equal and constituted from 3, 4±0,89% to 9, 5±0,79%. All in all from the patients with acute flaccid paralysis and contact persons we isolated 191 polioviruses, 60 of them belonged to type 1, 55 polioviruses were identified as types 2 and 76 as type 3. Some cases of vaccine-associated paralytic poliomyelitis are described in the article; polioviruses were isolated from all these patients. The sequencing of the genome fragments of 45 poliovirus strains showed that the majority of them had the nucleotide substitutions including neurovirulent substitutions. Conclusion:In order to prevent the risk of the appearance of vaccine-associated paralytic poliomyelitis it is necessary to maintain the high quality of surveillance of poliomyelitis and acute flaccid paralysis, to ensure the 95% coverage of children with poliomyelitis vaccine, to minimize the cases of groundless delays of vaccination according to medical recommendations and parents’ refusals to vaccinate children against poliomyelitis and to respect strictly the National calendar of vaccination.