Etiology of Enteroviral Meningitis in Ekaterinburg Before and the After Pandemic of COVID‑19

Introduction. The incidence of enterovirus meningitis in Ekaterinburg has long exceeded the average in Russia. As a result of sanitary, anti-epidemic and restrictive measures related to the COVID-19 pandemic, there was a decrease in morbidity, which led to a reduction in the circulation of non-polio enteroviruses and created risks after lifting of restrictions. The purpose of the study is to conduct a comparative analysis of non-polio enteroviruses isolated in Ekaterinburg from patients with enterovirus before and after the COVID-19 pandemic. Materials and methods. Genotyping positive samples by sequencing VP1 gene (cerebrospinal fluid, nasopharyngeal, faeces) from patients with aseptic meningitis was performed using the BLAST service. Multiple alignment and phylogenetic analysis were performed using the MEGA software. Results. In 2022, after lifting restrictive measures, the incidence of enteroviruses in Ekaterinburg increased 10 times compared to the previous year (3,390 per 100 thousand inhabitants), but remained 6.5 times lower than the long-term average (22,035 per 100 thousand population). 7 types of non-polio enteroviruses were detected: 2 species A (Coxsackievirus A4, Enterovirus A71) and 5 species B (Coxsackievirus A9 and B2, Echovirus 6, 7, 9). Coxsackievirus A9 dominated, followed by Echovirus 6. Discussion. In 2022, Coxsackievirus A9 prevailed as the predominant type in enterovirus, was not epidemiologically significant and was rarely found in the cerebrospinal fluid samples. Echovirus 6, the second most frequently detected, was characteristic of the Ural Federal District. The remaining viruses (Coxsackievirus A4 and B2, Echovirus 7 and 9, Enterovirus A71) were also detected in patients with enterovirus before the COVID-19 pandemic. Conclusion. After the cancellation of prophylactic measures after the COVID-19 pandemic, the incidence of enteroviruses in Ekaterinburg during 2022 increased due to the restoration of circulation of non-polio enteroviruses.