Outbreaks have been reported in hospitals, day-care centres, within households, among bathers (affecting participants in water sports in lakes and swimming pools), and in municipalities with contaminated public water supplies.
O izbruhih so poročali v bolnišnicah, centrih za dnevno nego, gospodinjstvih, med kopalci (prizadene osebe, ki se ukvarjajo z vodnimi športi v jezerih in bazenih) ter v občinah s kontaminirano vodo v javnih vodovodih.