Virological and genetic characteristics of human respiratory syncytial viruses isolated in Russia, 2017-2018

Abstract

Isolation of human respiratory syncytial virus (HRSV) from clinical samples and storage of isolates for long period remains a considerable problem. We describe in detail the optimized conditions of HRSV isolation and cultivation in three cell cultures HeLa, HEp-2, and Vero. HRSV was detected in 35.2% (166/471) specimens by real-time PCR from symptomatic infants and children up to 15 years from October 2017 to March 2018 in Russia. HRSV-positive samples were used for virus isolation in HeLa, HEp-2, and Vero cells in different manners (in monolayer or suspension). To optimize the conditions of HRSV cultivation, these cell cultures were treated or not with receptor-destroying enzyme (RDE). Ten isolates were successfully obtained by the way of infection of the suspension of cells with subsequent RDE treatment. Among them, several isolates induced the cytopathogenic effect (CPE) by the syncytium formation in both Hela and HEp-2 cell cultures. The genetic analysis revealed that the manners of isolation by using monolayer or suspension and subsequent RDE treatment did not influence the nucleotide and amino acid structures of obtained HRSVs. The CPE characteristics of obtained viruses were the same in HeLa, HEp-2, and Vero cell cultures, and were described as large syncytium up to 150 microns or more in size with the nuclei peripheral location and an optically bright zone in the center of the formation. We showed that infection of cell suspension with the subsequent RDE treatment increased the chance of HRSVs isolation from clinical samples.

Genetic Diversity of the Human Adenovirus C Isolated from Hospitalized Children in Russia (2019–2022)

“…In the study reported here, 3.98% of pediatric patients with ARI proved to be HAdV positive. Approximately similar data were obtained in China (3.78-7.0%) during the period 2017-2019 [9,22,24]. In our current research, the majority of the HAdV-positive cases (4%, 82/1836) were detected among children younger than 2 years.…”

“…At least one of these respiratory viruses was detected in 74.4% (2372/3190) of the hospitalized children. The lowest incidence of ARIs was registered among patients older than seven ( Table 1 ), as also determined in earlier works [ 21 , 22 , 23 ]. Those children 0–2 years old were the most sensitive to viral infections, with a 68% positive rate (1248/1836) (Chi-square test, p < 0.01).…”

“…In our current research, the majority of the HAdV-positive cases (4%, 82/1836) were detected among children younger than 2 years. A similar epidemic pattern was observed in Europe and Asia [ 22 , 25 , 26 , 27 ]. In total, co-infections of human AdVs with any other respiratory viruses were registered in 1.3% of cases during the period 2019–2022.…”

“…In our previous study, the absence of HIFV among circulated viruses during the period 2020–2021 was shown, as well as the absence of HMPV among other respiratory viruses during the subsequent period (2021–2022) [ 21 ]. In total, as shown in our previous work, the assessment reports about etiological agents of ARVI during the period 2019–2022 that HAdV presented at a lower rate, following HIFV, SARS-CoV-2, HRSV, and HMPV [ 21 , 22 ].…”

“…We randomly selected 30 samples out of 127 PCR positives with the lowest Ct values (18)(19)(20)(21)(22)(23), representing different ages and sexes, which we attempted to isolate in cell cultures. In order to study virological characteristics, five cell cultures of HeLa, HEp-2, Vero, SPEV, and Caco-2 were infected with the first human adenovirus (strain HAdVC/Novosibirsk/7.134V/2019) isolated at the beginning of the research period-in December 2019.…”