Shigellosis: an update on the disease and analysis of human cases in the Czech Republic, 2018-2023.

Introduction: Shigellosis is a highly contagious diarrheal disease, which could potentially be very serious. Considering the onethird increase in cases in 2023 compared to the previous year, we aimed to provide an update on the disease and to analyse data on reported cases of shigellosis in the Czech Republic (CZ).

Methods: We conducted a narrative search of the literature in Czech and English, particularly targeting European studies from 2018 onwards. We also analysed data reported under the diagnosis code A03 to the National Infectious Disease Reporting System (ISIN) in 2018-2023. We focused on the main epidemiological indicators, i.e. gender, age, geographical distribution, seasonality, and hospitalizations. Excel (version 2016), STATA (version 17), and Datawrapper GmbH were used.

Results: A total of 681 shigellosis cases were reported with an average annual incidence of 1/100,000 population: until 2021, the incidence was slightly higher in women, while from 2022 onwards, the trend was reversed. A significant decrease in cases was recorded in the pandemic years. In 2022 and 2023, the number of cases was slightly higher than in the pre-pandemic period. Most cases were detected in CZ in August and December each year. Of all shigella serotypes, S. sonnei was the most frequently detected (80%), followed by S. flexneri (15%). The incidence per 100.000 population was highest among children aged 5-9 years: 2.6 (boys 2.4 and girls 2.8), followed by 1-4-year-olds: 2.4 (2.2 and 2.6, respectively) and persons aged 25-34 years: 1.8 (males 1.8 and females 1.7). Within individual age group, the average annual specific incidence rates were highest in the Moravian-Silesian and Olomouc regions and the capital city Prague. Hospitalizations accounted for 27% of cases, with the highest numbers in the 25-34 and 5-9 age groups (both 17.9%). The proportion of hospitalized cases was highest in the age groups 75+ (69%), 1-4, 5-9, and 65-74 (32-37%). A 52-year-old man was reported to have die in relation to the disease. Eleven percent of cases were reported in outbreak settings. Thirty-nine percent of reported cases were imported.

Conclusions: In CZ, shigellosis is a relatively rare gastrointestinal disease, with nearly 40% of cases being imported. At present, the threat to public health is posed mainly by the global spread of multi-resistant strains linked to increasing tourism and free sexual practices. Children, immunocompromised persons (including the elderly), and men who have sex with men remain risk groups. Vaccination is not available in Europe. Compliance with basic hygiene rules, especially in collectives and when working with food, is still a key concern. Emphasis should also be placed on the health education, including instructions before traveling abroad. A thorough medical history, early tracing, surveillance, and rational choice of antibiotic therapy if appropriate are essential. In CZ, all suspected strains shall be sent to the NRL for confirmation. Whole genome sequencing and antibiotic susceptibility testing should be performed on all isolates.