Objectives:
Among infectious diseases in Poland there are two caused by Legionella pneumophila: pneumonic legionnaires’ disease and non-pneumonic legionnaires’ disease (Pontiac fever). The level of prevalence of these diseases in Poland is significantly lower than in other European countries.

Objective:
The aim of the study was to assess the suitability of the Polish hospital morbidity database for the purposes of epidemiological analysis of diseases caused by L. pneumophila.

Material and methods:
The analysis was based on population-based administrative data, collected between January 2008 – December 2015. The analyzed data covered 84 first time hospitalizations for legionnaires’ disease (ICD-10 code: A48.1) and non-pneumonic legionnaires’ disease (Pontiac fever) (ICD10 code: A48.2), and other available data included in the infectious disease reporting system.

Results:
The obtained data indicated more frequent occurrence of the disease in men than in women and in people living in more urban areas in relation to people living in more rural areas. Patients were mainly hospitalized in internal wards (22,62%), pulmonology wards (19.05%) and infectious diseases wards (11,91%), and less frequently in other hospital wards. On average, hospitalization time amounted to 14,68 days. Legionellosis was the sole reason for hospitalization in 30.95% of patients, whereas in the remaining patients (n=58) comorbidities were observed. Seasonality of hospitalizations was observed in this study with a higher incidence in the summer season.

Conclusions:
It was shown that neither hospital morbidity data nor other sources of information on diseases caused by L. pneumophila in Poland are sufficient for a full epidemiological analysis. It was concluded that the diagnosis of diseases with symptoms of L. pneumophila infection should include an analysis of environmental factors, and in the case of their occurrence, microbiological tests should be performed.