Legionella pneumophila, a microscopic bacterium usually responsible for a number of illnesses and fatalities, can eliminate a local population, a region or even a nation. In 1976, L. pneumophila was first discovered due to a number of cases presenting with pneumonia-like symptoms. These cases occurred in an isolated population attending an American Legion convention in Philadelphia, Pennsylvania, therefore lending to the name Legionella. Usually found in aquatic environments such as lakes, streams, cooling towers, air conditioning systems and hot tubs, its ability to thrive in artificial and natural environments makes it an ideal bacterium. L. pneumophila can be transmitted via inhaling aerosols that contain the pathogen. After inhalation, the alveolar macrophages phagocytize the pathogen which then serves as its host Virulence factors such as lipopolysaccharides (LPS), are one way the pathogen causes infection, however it can also utilize heat shock protein and surface antigens. Usually with Legionnaires' disease the physical symptoms consist of high fever, malaise, muscle aches, rigors, confusion, headache and diarrhea which categorizes this pathogen as causing an atypical pneumonia. Since L. pneumophila may be associated with travel-related infections, it is hard to track and isolate travel-associated incident clusters because the symptoms present themselves after returning from travel. In regard to diagnosis, this disease has five available techniques to confirm that the patient is in fact positive for L. pneumophila. Programs such as the Environmental Legionella Isolation Techniques Evaluation Program (ELITE) have been started by the Centers for Disease Control and Prevention (CDC) in order to decrease outbreak incidences. Additionally, the current recommendations for the management of Legionnaires' disease adapted from the CDC have been summarized into a flow chart which may help clinical decisions in the treatment of this disease.
Harklerode J, Henton O, Smith M, Worden R, Roecker A. Legionnaires' Disease, A Rising Occurrence in the United States. PAW Review. 2016 Jan 01; 7(2):Article 5 39-43 . Available from: https://digitalcommons.onu.edu/paw_review/vol7/iss2/5. Free full text article.