Prevalence of parvovirus infection in the Northwestern federal district of Russia

Here, we analyze the spread of parvovirus B19 infection in the Northwestern Federal District from the years 2018 to 2023. It was shown that cases of infection were recorded in 10 out of 11 territories, excepting the Nenets Autonomous Okrug. Overall, IgM antibodies to parvovirus B19 (B19V) were detected in 295 samples out of 2079 tested (14.1%). The prevalence of parvovirus B19 infection varied over the years of the study: in 2023, an increase in incidence was detected in the Northwestern Federal District, with an indicator of 0.93 per 100 thousand population, which significantly exceeded the long-term average level of 0.43 per 100 thousand population in the district. Children under 14 years of age predominated in the age pattern. The virus circulated most actively in St. Petersburg and the Leningrad region, which is due to the high population density in these territories and the many municipal institutions where long-term close contacts between people take place. The winter-spring seasonality of the infection has been confirmed. An analysis of primary diagnoses in patients with laboratory-confirmed parvovirus infection (2022) showed that the correct clinical diagnosis was not established in any case. The most common clinical diagnostic errors were: “Acute respiratory infection”; “Measles” and “Rubella”; herpes virus infections. In 30% of cases, parvovirus B19 infection was assessed by clinicians as a non-infectious disease. Errors in the initial diagnosis of parvovirus infection can contribute to the spread of infection, including in risk groups. Thus, while examining patients at a dialysis center, laboratory methods revealed latent parvovirus B19 circulation in this risk group confirmed by the detection of B19V DNA and virus-specific IgM antibodies in some samples tested. The seroprevalence established among patients not exceeding 76.9% accounts for an opportunity of infection spread among patients seronegative for parvovirus B19 with worsening of disease course and prognosis. Considering the widespread distribution of parvovirus infection, when identifying infectious diseases and respiratory diseases that occur with unclear exanthema manifestations among people at risk and/or from organized groups, it is advisable to conduct targeted serological monitoring for laboratory markers of parvovirus B19 infection. One of the directions for further qualitative study of parvovirus infection is to solve an issue of its identification and recording in the epidemiological surveillance system.