UNASSIGNED: The aim of this study is to compare the epidemiological situation of legionellosis in Poland in 2018-2021 to prior years, taking into account the impact of the COVID-19 pandemic in 2020-2021.
UNASSIGNED: The assessment is based on national surveillance data published in the annual bulletin \"Infectious Diseases and Poisons in Poland\" from 2013 to 2021, as well as data from Legionnaires\' disease case reports collected and sent to the Department of Epidemiology of Infectious Diseases and Surveillance NIPH NIH - NRI by sanitary and epidemiological stations or submitted to EpiBase.
UNASSIGNED: In Poland, both Legionnaires\' disease (an acute infection that progresses to pneumonia) and Pontiac fever (a mild, flu-like sickness) are reported. In 2018-2021, a total of 255 cases of legionellosis were registered, including 236 cases of Legionnaires\' disease and 19 cases of Pontiac fever. Each year, there was an increase in the number of notifications compared to the annual median number of cases from 2013-2017. The annual incidence rate in 2019 (0.23 per 100,000 population) was the highest since the start of legionellosis case registration in Poland. It declined again during the years of the COVID-19 pandemic. The notifications occurred throughout the country, but the highest notification rate was observed in the western belt of voivodeships. Pomorskie reported the highest incidence, accounting for more than 20% of all registered cases. The median incidence of Legionnaires\' disease in men (0.23 per 100,000) was more than twice that of women (0.10), with the highest incidence (0.58) recorded in men 65 years of age or older. All indigenous cases of Legionnaires\' disease were sporadic; all but three patients were hospitalized. State Sanitary Inspection reported 26 fatal cases of Legionnaires\' disease (mortality = 11%). Twenty-four cases were linked to contaminated water systems in health-care settings, and 21 cases were likely associated with travel abroad.
UNASSIGNED: Although the number of notifications has increased in recent years, Legionnaires\' disease is still an infrequently diagnosed respiratory infection in Poland, and the reported incidence remains one of the lowest in the entire EU. The most affected demographic group is men aged 65 and older. Improving the early diagnosis of Legionnaires\' disease in healthcare settings remains a priority.

Legionella are opportunistic intracellular pathogens that are found throughout the environment. The Legionella contamination of water systems represents a serious social problem that can lead to severe diseases, which can manifest as both Pontiac fever and Legionnaires\' disease (LD) infections. Fluorescence in situ hybridization using nucleic acid mimic probes (NAM-FISH) is a powerful and versatile technique for bacterial detection. By optimizing a peptide nucleic acid (PNA) sequence based on fluorescently selective binding to specific bacterial rRNA sequences, we established a new PNA-FISH method that has been successfully designed for the specific detection of the genus Legionella. The LEG22 PNA probe has shown great theoretical performance, presenting 99.9% specificity and 96.9% sensitivity. We also demonstrated that the PNA-FISH approach presents a good signal-to-noise ratio when applied in artificially contaminated water samples directly on filtration membranes or after cells elution. For water samples with higher turbidity (from cooling tower water systems), there is still the need for further method optimization in order to detect cellular contents and to overcome interferents\' autofluorescence, which hinders probe signal visualization. Nevertheless, this work shows that the PNA-FISH approach could be a promising alternative for the rapid (3-4 h) and accurate detection of Legionella.

Bacteria Legionella sp. found in water distribution systems, especially warm, transferred to water spray devices for aerators and showers in the form of aerosols infected with them become a threat to the human inhaler.
Assessment of colonization of the water supply network with Legionella bacteria in teaching and education facilities in Małopolska in 2016 year.
The results of water samples taken from plumbing installations were analyzed in teaching and education facilities by employees of the State Sanitary Inspection of the Lesser Poland Voivodeship.
The results of 366 testing hot water samples in 111 teaching and education centers in Małopolska have shown that in 123 testing samples (33,6%) in 48 centers (43,2%) the water sample was colonized with Legionella sp. and the water quality did not meet the requirements of the current ordinance of the Minister of Health.
It is justified to periodically monitor the presence of Legionella sp. in water supply installations in teaching and education centers and taking action to reduce the colonization of these bacteria.

The aim of this study is to assess the epidemiological situation of legionellosis in Poland in 2017 in comparison with previous years.
The analysis is based on national surveillance data published in the annual bulletin: “Infectious diseases and poisonings in Poland in 2017” and bulletins from previous years along with data from legionellosis case reports collected and sent to the Department of Epidemiology of Infectious Diseases and Surveillance NIPH – NIH by Sanitary and Epidemiological Stations.
In Poland, both cases of Legionnaires’ disease (an acute form of infection with pneumonia) and Pontiac fever (a mild, influenza-like form of infection) are routinely reported to the surveillance system. In 2017, a total of 39 cases of legionellosis were registered, including 38 cases of Legionnaires’ disease and 1 case of Pontiac fever; the annual incidence rate 0.102 (per 100,000 population) has increased by almost 50 percent since previous year (0.070) and is almost three times higher than the median incidence (0.036) for 2011-2015. The infections were reported in fourteen voivodeships; only one voivodeship (Świętokrzyskie) did not register any case in last years. The incidence in men (0.129 per 100,000) was higher compared to women (0.076); the highest incidence (0.323) was noted in men aged 50-59. All reported cases were sporadic and were hospitalised. The Sanitary Inspection reported nine fatal cases – 6 women and 3 men. Thirty three cases were autochthonous including four cases linked with contaminated water systems in health-care settings. Six cases were associated with travels abroad (to Egypt, Albania, Italy and Crete).
Although in recent years number of reported cases continues to rise, the incidence of legionellosis in Poland remains one of the lowest in the entire EU. Also draws attention variation of incidence between provinces and a high mortality among reported cases. Our data suggest significant under-diagnosis of legionellosis. A priority remains to improve early diagnosis of Legionnaires’ disease in health care settings.

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

The aim of the study was to assess the epidemiological situation of legionellosis in Poland in 2015 in comparison to the preceding years.
We reviewed data published in the annual bulletin: “Infectious diseases and poisonings in Poland in 2015” and its prior versions along with the legionellosis case reports sent from Sanitary- Epidemiological Stations 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 notifiable. In 2015, a total of 23 cases of Legionnaires’ disease have been reported (there were no reports of Pontiac fever). The annual incidence rate 0.060 (per 100,000 population) slightly increased when compared to previous year as well as to the median (incidence) for 2009-2013. The infections were reported in 10 provinces, including five, which in previous years usually did not register any cases; however, there is a number of provinces that did not identify any LD cases in recent years. The incidence in males (0.097 per 100,000) was almost 4-times higher compared to females (0.025). Except for one cluster of two, all cases were sporadic; All patients required hospitalization. The Sanitary Inspection reported four fatal cases – all men 43- 67 years/old. Eighteen cases were likely acquired in the country, including a cluster of two cases linked with contaminated building water system. Four cases were associated with travels abroad (to Russia, Croatia, United Arab Emirates and USA) and in one case the exposure occurred during the transport of goods (lorry driver).
This study suggests, that legionellosis is likely under recognized and under diagnosed in all provinces of the country. Geographical variations in incidence may reflect local differences in availability of laboratory tests for LD. Number of detected cases - without information on the number of laboratory tests performed - do not appear to be sufficient to fully assess the epidemiological situation.

OBJECTIVE: The objective of the article is to assess the epidemiological situation of legionellosis in Poland in 2012 in comparison to the preceding years.
METHODS: The analysis of epidemiological situation was based on the data published in the annual bulletin: \"Infectious diseases and poisonings in Poland in 2012\" and its prior versions as well as the legionellosis case reports sent to the Department of Epidemiology of NIPH-NIH.
RESULTS: In Poland, all cases of legionellosis, including Legionnaires\' disease - a form of disease accompanied by pneumonia and mild, influenza-like form of infection - Pontiac fever are routinely reported to the surveillance. In 2012, a total of 10 legionellosis cases were reported (8 cases of Legionnaires\' disease and 2 cases of Pontiac fever); the incidence was 0.026 per 100 000 population which compared to the previous year and median incidence for 2006-2010 was 45% and 65% lower, respectively. The infections were reported in 6 provinces. The incidence in males (0.03 per 100 000) was slightly higher compared to females (0.02). No legionellosis outbreaks were registered - all infections were of sporadic nature. All cases were hospitalized. The sanitary inspection reported two fatal cases over the age of 60. Of these infections, seven were developed in the country, including one hospital- and one sanatorium-acquired infection. Two infections were associated with travels abroad (one to Spain and one to Egypt) and one infection occurred in driver while transporting the goods to the Netherlands.
CONCLUSIONS: In 2012, no changes of fundamental features of legionellosis epidemiological situation in Poland were observed. It is recommended to enhance the surveillance for legionellosis, with emphasis on conducting environmental investigation in areas where infections have occurred.