Switzerland: Number of legionellosis cases has increased fivefold since 2000

The number of cases of legionellosis in Switzerland has increased fivefold over the past 20 years. A study published in the International Journal of Hygiene and Environmental Health by the Swiss Tropical and Public Health Institute (Swiss TPH) analyzes the number of cases from 2000 to 2020 and sheds light on the possible impact of the COVID-19 pandemic on reporting figures. In recent years, researchers have observed an increase in the number of cases during the summer months, Swiss TPH reported. Switzerland has one of the highest incidences of legionellosis in Europe. Legionellosis is caused by bacteria of the genus Legionella and occurs in two different forms, the more severe and widespread of which is known as Legionnaires' disease. The Legionella bacteria are transmitted through water or soil and can cause severe pneumonia. Although the disease can be treated with antibiotics, it is fatal in around ten percent of all cases, according to the institute. Legionnaires' disease is notifiable in Switzerland. The number of cases is monitored by the Federal Office of Public Health (FOPH). Since 2000, the number of reported cases of legionellosis in Switzerland has risen steadily, from 140 cases per year at the beginning of the 2000s to around 500 per year between 2016 and 2020, Swiss TPH explained in more detail. The upward trend reached a temporary peak in 2018 and stabilized at this level. It was only in 2020 that the number of cases fell again, presumably in connection with the COVID-19 pandemic, the researchers say in their study....