Legionnaires Disease - Poland

Situation at a glance

As of 11 September 2023, a total of 166 cases of Legionnaires' Disease, including 23 deaths, have been reported from Poland. 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.

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 Legionella among patients admitted to several hospitals in Rzeszów.

Public health response

• Meetings of the crisis staff at the Mayor of Rzeszów are held daily.

• Water samples were collected from the water supply system, residences of the sick, healthcare facilities, cooling towers, and installations in buildings located in Rzeszów, the Rzeszów poviat, and the Ropczyce and Sędziszów poviat.

• An epidemiological investigation, including interviews with patients or relatives, is underway to determine the source of infection.

• Mapping all positive cases, water sampling sites, and cooling towers is underway.

• Public fountains, public water sprays, and other public water sources have been shut down temporarily.

• Rzeszów Municipal Water and Sewage Company carried out the routine disinfection of the water supply in the city of Rzeszów and adjacent towns on 27 August 2023.

• Health care units and long-term care facilities have been instructed to carry out additional inspections of their water systems.

• Public health advice has been developed and shared across multiple channels.

WHO advises against applying any travel or trade restrictions on Poland based on the current information available on this event.