A major Legionella outbreak in the Polish city of Rzeszów and surrounding region has already caused the deaths of 19 people, local health officials said on Saturday.
All of the deceased had also had other illnesses, the health department in the south-eastern city reported. The number of people infected with the bacterium has risen to 160, of whom 107 came from Rzeszów itself, according to the report.
The city, with a population of about 196,000, is located around 250 kilometres south of Warsaw, towards the border with Ukraine.
Legionella can cause flu-like symptoms and even severe pneumonia in humans. The pathogens are often transmitted through atomized water, for example in showers, whirlpools, through humidifiers or via water taps.
The bacteria are found in low concentrations almost everywhere in water, and find ideal growth conditions at temperatures between 25 and 45 degrees Celsius.
People with a weakened immune system or with certain underlying diseases such as diabetes and heart and lung conditions are particularly susceptible to Legionella.
Smokers and older people are also considered to be more at risk. The associated Legionnaires' disease is fatal in about 5-10% of patients.
