Epidemic process of acute intestinsl infections in Ukraine against the background of the COVID-19 epidemic

Abstract

Background. Acute intestinal infections (OII) are among the most common infectious diseases. Rotaviruses, Shigella, and Salmonella are the main etiological factors of mortality from OII worldwide.

The goal of the work. Study of the dynamic of the epidemic process of acute intestinal infections and the possible impact of the COVID-19 epidemic on its characteristics in Ukraine.

Materials and methods. A retrospective analysis of the incidence of OII (on the example of salmonellosis, shigellosis, and rotaviral enteritis) in Ukraine in multi-year dynamics was carried out. Analyzed statical forms 1,2 "Report on certain infectious and parasitic diseases", statistical form 40-health "Report on the work sanitary-epidemiological stations" for 2015-2022. To study the possible impact of the COVID-19 epidemic on the epidemic process of intestinal infections were the pre-epidemic period and the epidemic period (2020-2021)one highlighted. The method of quantization of administrative territories by quartiles (Q) was used for the analysis of morbidity by region. Quantitative measurements of changes during the epidemic process were evaluated by the indicator of the average rate of increase|decrease in morbidity (Tser.). The probability of the obtained was estimated by the value of the average error (for relative indicators) with the calculation of the confidence t-criterion according to the formulas for average and relative indicators, the difference was considered probable at t >=2.

Results and discussion. In the long-term dynamics of the incidence of zoonotic salmonellosis in Ukraine, two pronounced increases in its level were noted: in 1974-1979 and 1989-1996. During the 5 years before the COVID-19 pandemic, the incidence of salmonellosis averaged 1925 per 100,000 populations. In 2020-2021, the incidence rate decreased by 2.3 - 2.5 times compared to the last pre-epidemic year. The period until the end of the 70s was characterized by high morbidity, mortality, and intensive spread of shigellosis. The average incidence rate of shigellosis in Ukraine in the period 1999-2009 was 23.41 per 100,000 population, the incidence tended to decrease. In 2010-2015, the registered morbidity rates ranged from 3.55 (2011) per 100,000 population to 6.13 (2012), the overall trend was stable. A more pronounced tendency to decrease the incidence of Zonner`s than Flexner`s shigellosis was noted. In 2021-2022, the incidence rate of shigellosis was 4 times lower (o.48 and 0.54 per 100.000 populations) than in the pre-epidemic period. In contrast to bacterial acute intestinal infections, the incidence of rotavirus (RV) enteritis in Ukraine, after a significant decline in 2017-2020, began to increase during the period of the COVID-19 pandemic (2021-2022), although its level did not reach the indicators are pre-pandemic period. Despite the lack of routine immunization against RV infection in Ukraine, the age structure of patients showed a significant decrease in the share of children under 4 years of age (the main age groups at risk for rotavirus enteritis) against the background of a significant increase in the share of older age groups, especially adolescents aged 15-17.

Conclusions. During the COVID-19 epidemic, the incidence of RV enteritis increased, while the incidence of bacterial intestinal infections (salmonellosis and shigellosis) decreased significantly. The nosogeography of the epidemic process of salmonellosis and shigellosis did not change during the COVID-19 epidemic.