Sweden: Pertussis, Mpox and Legionella outbreak updates
Pertussis
In 2024, a total of 355 cases of whooping cough, or pertussis have been reported through June 16 in Sweden, according to the Folkhalsomyndigheten, or Public Health Agency of Sweden.
Of the cases, 43 cases have been children under the age of 1. During May, 100 cases were reported, of which 16 were among children under 1 year of age. During the first half of June (until 16 June) 85 cases have been reported, of which 12 cases were among children under 1 year of age.
Cases in June have been reported from 15 regions. The majority (63 percent) of the cases have been reported from the Stockholm, Skåne and Västra Götaland regions.
Mpox
Health officials report since the start of the outbreak in April 2024, 27 cases of mpox have been reported so far, the majority in the Stockholm region.
All cases are adult men who fell ill during the period 7 April – 2 June and are infected in Sweden. The majority of cases are unvaccinated.
Developments over the past month suggest that the current outbreak is over. The Public Health Authority assesses that mpox will continue to spread in around the world, which could lead to new outbreaks in Sweden.
Legionella
During the spring and early summer, the Public Health Authority, in collaboration with the infection control units, has noted an increase of cases of illness caused by the bacterium Legionella longbeachae, which is associated with infection via soil and compost.
A total of 17 cases have been reported since the beginning of May, the most recent of which was on June 25. The majority of cases have been reported during the second half of June. Approximately half of the cases have been reported from Stockholm County and the other cases from various parts of southern Sweden. Most cases have been exposed to soil during gardening.
Legionella infection is most often caused by Legionella pneumophila, but each year a number of cases caused by other species are reported, including L. longbeachae. The number of L. longbeachae cases reported so far this year is higher than in an average year. In 2018, about 40 cases of legionella infection were reported that could be linked to gardening and exposure to different types of bagged soil, compost and other soil products, which led to an extensive outbreak investigation. No single common source of infection could be identified for the cases that had been reported from six different regions.
Legionella bacteria can cause the more serious Legionnaires' disease or the milder flu-like Pontiac fever. Advice to reduce the risk of being infected via soil is to avoid breathing in the soil when handling, gently moisten the soil so that it becomes less dusty, and to wash your hands after handling.