Shigellosis in Poland in 2013-2017

Abstract

Aim: The purpose of this study evaluation of the epidemiological situation of shigellosis in Poland in years 2013-2017.

Materials and methods: The evaluation was based on analysis of : data gathered and sent to Department of Epidemiology of Infectious Diseases and Surveillance in NIPH-NIH by local and voivodeship sanitary stations in the form of epidemiological questionnaires. It was also based on aggregated data from annual bulletins “Infectious diseases and poisonings in Poland” as well as data from shigellosis outbreaks acquired through ROE system (an electronic system created for uploading, transfer and analysis of data from the outbreak investigations). All cases were reported according to the Decision 2008/426/WE.

Results: In the years 2013-2017 in Poland 140 shigellosis cases were reported. Mean incidence per 100 000 was 0.05. A decrease of incidence median for years 2013-2017 was observed comparing to preceding, 5- year period by 0,03. Slightly over half of cases (51%) belonged to the age group 20-44. Majority of cases were males (57.1%). In each year from described period percentage of hospitalizations was over 70%. Imported cases amounted for 28% of all cases reported in that period- most of them being imported from countries from outside UE/ EFTA. In years 2013-2017 there were 10 outbreaks of shigellosis registered, in which 47 persons got ill.

Conclusions: In years 2013-2017 no clear increasing or decreasing trend in shigellosis cases was observed, however in years when epidemic outbreaks occurred there was a significant increase in the number of cases reported yearly. Because of low number of cases being reported every year, an occurrence of large outbreak may result in seasonal peak of cases shifting, which was the situation in 2017 when most cases onset was in October, while in other years it was in September. High percentage of hospitalizations in cases could mean that severe cases are more readily reported, and in the same time that other cases are underreported. Because the date on shigellosis cases are acquired through general, not shigella-specific questionnaire it may result in incomplete or missing data on exposure (e.g. information on risk group affiliation), and therefore impairs the epidemiological situation assessment. It points the need of introduction Shigella- specific questionnaire.

Keywords: shigellosis; epidemiology; Poland; years 2013-2017.