Legionellosis in Poland in 2016

OBJECTIVE: The aim of the study was to assess the epidemiological situation of legionellosis in Poland in 2016 in comparison to the preceding years.

MATERIAL AND METHODS: The assessment was based on national surveillance data published in the annual bulletin: “Infectious diseases and poisonings in Poland in 2016” and its prior versions along with data from legionellosis case reports sent from Sanitary-Epidemiological Stations to the Department of Epidemiology of NIPH - NIH.

RESULTS: In Poland, both two main forms of legionellosis - Legionnaires’ disease and Pontiac fever are routinely reported to the surveillance system. In 2016, a total of 27 cases of legionellosis were registered, including 25 cases of Legionnaires’ disease and 2 cases of Pontiac fever; in 2016, a total of 27 cases of legionellosis have been reported, including 25 cases of Legionnaires’ disease and 2 cases of Pontiac fever; the annual incidence rate 0.070 (per 100,000 population) was comparable to previous year (0.060) but almost twice as high as the median (incidence) for 2010-2014. The infections were reported in 11 provinces, including two, which in previous years usually did not register any cases; only two provinces (out of 16 in the country) have reported no cases in recent years. The incidence in men (0.080 per 100,000) was higher compared to women (0.055). All reported cases were sporadic and, except for one mild case of Legionnaires’ disease, required hospitalization. The Sanitary Inspection reported two fatal cases – both women aged 59 and 69. Twenty cases were autochthonous including four cases linked with contaminated water systems in hospitals. Seven cases were associated with travel abroad (to Germany, Russia, Greece, Australia, USA and Thailand).

SUMMARY AND CONCLUSIONS: Despite the increase in the number of cases in recent years as well as number of provinces, which detected cases, the annual incidence of legionellosis in Poland remains one of the lowest in the EU, which suggests that this infection is likely under-recognized and underdiagnosed in all provinces of the country.