Situation at a glance

As of 11 September 2023, a total of 166 cases of legionellosis, including 23 deaths, have been reported from Poland. Legionellosis, more commonly known as Legionnaires’ disease, is a pneumonia-like illness, caused by a bacterium, that varies in severity from mild to a severe illness and sometimes fatal form of pneumonia.

Image by PublicDomainPictures from Pixabay

This observed increase in confirmed cases, and associated hospitalizations and deaths seen since mid-August, is unusual, considering that the number of cases is higher than the annual number reported in Poland since 2016.

Polish health authorities are coordinating cluster investigation activities, active case finding to identify additional cases, and public health activities to prevent transmission and limit the emergence of new cases, through preventive control measures. Since 7 September, no new cases have been reported, although the infection source has not yet been identified. Investigations are still ongoing to find the source of the outbreak.

Most people develop Legionnaires’ disease by inhaling the bacteria from water or soil. To date there has been no reported direct human-to-human transmission.

Description of the situation

On 18 August 2023, public health authorities in Rzeszów, Poland, announced the detection of a cluster of 158 suspected community-acquired pneumonia cases, including 15 laboratory-confirmed cases of legionellosis among patients admitted to several hospitals in Rzeszów.

Between 18 August and 11 September 2023, a total of 166 laboratory-confirmed cases, all hospitalized, and 23 associated deaths (CFR of 14%) have been reported. Most cases, 67% (n=112), were recorded in the city of Rzeszów, 23% (n=38) of cases in Rzeszów county, and 10% (n=16) cases in other locations.

Read more at World Health Organization