Legionella: Infections and PathologyAbout This Hardback Legionella refers to a genus of pathogenic bacteria which can cause diseases such as legionellosis, Pontiac fever and Legionnaires' disease. Their symptoms are similar to pneumonia. Complicated cases might also lead to issues related to the gastrointestinal tract and nervous system. The infections generally spread by the inhalation of water droplets from a source in which the bacteria has spread. It has not been observed to spread