An outbreak investigation of Legionella non-pneumophila Legionnaires' disease in Sweden, April to August 2018: Gardening and use of commercial bagged soil associated with infections.
In early June 2018, an increase in non-travel-related cases of Legionella non-pneumophila Legionnaires' disease (LD) was observed in Sweden and a national outbreak investigation was started. Outbreak cases were defined as notified confirmed or probable cases of L. non-pneumophila LD, with symptom onset after 1 April 2018. From April to August 2018, 41 cases were reported, 30 of whom were identified as L. longbeachae. We conducted a case-control study with 27 cases and 182 matched controls. Results from the case-control study indicated that gardening and handling commercial bagged soil, especially dusty dry soil, were associated with disease. L. longbeachae was isolated in soils from cases' homes or gardens, but joint analysis of soil and human specimens did not identify any genetic clonality. Substantial polyclonality was noted between and within soil samples, which made finding a genetic match between soil and human specimens unlikely. Therefore, whole genome sequencing may be of limited use to confirm a specific soil as a vehicle of transmission for L. longbeachae. Handling soil for residential gardening was associated with disease and the isolation of L. longbeachae in different soils provided further evidence for Legionella non-pneumophila infection from soil.
['Löf|Emma|E|', 'Chereau|Fanny|F|', 'Jureen|Pontus|P|', 'Andersson|Sabina|S|', 'Rizzardi|Kristina|K|', 'Edquist|Petra|P|', 'Kühlmann-Berenzon|Sharon|S|', 'Galanis|Ilias|I|', 'Schönning|Caroline|C|', 'Kais|Madeleine|M|', 'Tideholm Nylén|Anne|A|', 'Wallensten|Anders|A|', 'Roth|Adam|A|', '|||']
D016022:Case-Control Studies D004196:Disease Outbreaks D051639:Gardening D006801:Humans D044128:Legionella longbeachae D016952:Legionella pneumophila D007877:Legionnaires' Disease D012987:Soil D013548:Sweden
outbreak Legionella non-pneumophila soil Legionella longbeachae Legionnaires’ disease case control study