Legionellosis in Poland in 2014

The aim of the study was to assess the epidemiological situation of legionellosis in Poland in 2014.

We reviewed data published in the annual bulletin: “Infectious diseases and poisonings in Poland in 2014” and its prior versions along with the legionellosis case reports sent to the Department of Epidemiology of NIPH - NIH.

In Poland, both two forms of legionellosis - Legionnaires’ disease (a severe form of disease accompanied by pneumonia) and Pontiac fever (mild, influenza-like form of infection) - are routinely reported to the surveillance. In 2014, a total of 14 cases were reported (12 cases of Legionnaires’ disease and 2 cases of Pontiac fever); the incidence (0.036 per 100,000 population) was comparable to previous year as well as the median (incidence) for 2008-2012. The infections were reported in eight provinces, including five, which in previous years usually did not register any cases. The incidence in males (0.04 per 100,000) was slightly higher compared to females (0.03). Death rate of females was unusually high = 75%. No outbreaks or clusters were reported - only sporadic cases. All patients required hospitalization, including cases of Pontiac fever. The Sanitary Inspection reported three fatal cases – all women 49- 60 years/old. Twelve cases were likely acquired in the country, including two probably in hospital and three linked with inhalation of aerosols during professional activity. Two cases were associated with travels abroad (one to Italy and one to Germany).

In 2014 diagnosis of legionellosis cases was confirmed by rapid chromatographic test detecting legionella antigen in urine. The examinations were performed even in small town hospitals, so infections were detected and reported in provinces which usually did not register any cases. This study suggests, that legionellosis is likely under recognized and under diagnosed in all provinces of the country. Presumably physicians often do not suspect or not confirm the clinical diagnosis of Legionnaires’ disease in cases with atypical pneumonia.