Basel health authorities believe they have identified the source of the Legionnaires’ disease epidemic currently affecting the region. At an emergency press conference on Monday, the Health Department announced that two cooling towers installed on the roof of an office building in Kleinbasel were most likely the source of the contamination.
To date, 26 cases have been recorded. Twenty-five people had to be hospitalized, including seven in intensive care. One person has died and another remains in critical condition.
Investigations focused on cooling towers after an unusual concentration of cases was discovered in Kleinbasel. Of the ten installations inspected, eight had legionella limit values exceeded. However, only the two Rebgasse installations contained bacteria that were pathogenic for humans. They were immediately put out of service. The other six facilities were contaminated by strains considered harmless.
According to the Department of Health, the bacteria may have spread in the form of water droplets (aerosols) released from cooling towers. Depending on weather and wind conditions, these aerosols can be carried some distance before being inhaled.
The authorities invite people suffering from pneumonia to consult a doctor quickly. They also ask operators of large water cooling towers to make themselves known to the cantonal laboratory in order to facilitate controls in the event of possible future epidemics.
What is Legionnaires’ disease?
Legionnaires’ disease is an infection caused by bacteria called legionella, which thrive in lukewarm water systems or poorly maintained cooling facilities. Contamination occurs by breathing in fine droplets of contaminated water, not by drinking water. The disease can take two forms: Pontiac fever, usually mild, which is flu-like with fatigue, headaches and body aches. Legionnaires’ disease, on the other hand, is a much more serious form. It causes pneumonia, high fever, severe cough and chest pain. The elderly, immunocompromised or suffering from chronic illnesses are most exposed to severe forms.
