Detection and type identification of non-polio enteroviruses in children against the background of acute intestinal infections of various etiologies: 2018–2023

Introduction. Enteroviruses (EV) are characterized by: species and type diversity, polymorphism of clinical manifestations, a tendency to epidemic spread, and are often the cause of disease outbreaks, which determines the relevance of monitoring EV strains in various clinical forms of infection, including in conditions of anti-epidemic measures. The aim of the study: to characterize the prevalence and diversity of non-polio enteroviruses (NPEV) types in children with acute intestinal infection (AII) in the period 2018–2023, including the COVID-19 pandemic. Materials and methods. The RT-PCR method was used to study 7302 samples of feces from children hospitalized with a diagnosis of AII in the infectious diseases hospital of Nizhny Novgorod. Genotyping of EV strains was carried out using fragment Sanger sequencing of the genome region encoding capsid protein 1 (VP1) and the online resource BLAST. Results. EVs were found in 5.0 ± 0.3% (1.7–7.8%), both in mono- and mixed infections with other enteric viruses. The long-term dynamics of the frequency of EV detection and the incidence of EV infection in children in the Nizhny Novgorod region was characterized by a sharp decrease in indicators in 2020 against the backdrop of the introduction of anti-epidemic measures. When genotyping 299 strains, 41 types of NPEV of 4 species were identified. The spectrum included the main pathogens of exanthema and neuroinfections and rare types found in “minor” or intestinal forms of infection. During the study period, a redistribution of NPEV species was established. Before the pandemic, the ratio of Enterovirus A : Enterovirus B : Enterovirus C species was as follows — 41.0 : 46.7 : 12.3%; during the 2020 pandemic season the ratio was 0.0 : 37.5 : 62.5%; after the lifting of restrictive measures — 47 : 29 : 23%, which may be due to the different effectiveness of the restrictive measures on the mechanisms of transmission of EVs of different types. Conclusion. The genetic diversity of NPEVs detected in children with AII complements information on the typical composition of the territorial enterovirus population. In children with AII, when the airborne transmission of SARS-CoV-2 was blocked, there was a decrease in the frequency of detection of viruses of the Enterovirus B type, the absence of detection of Enterovirus A and the constant presence of Enterovirus C.