Legionella

Abstract This chapter summarizes the epidemiology, pathogenesis, clinical features, diagnosis, and management of Legionella pneumophila infection. It describes environmental reservoirs, transmission through aerosolized contaminated water, and the organism’s intracellular survival in alveolar macrophages. The two clinical presentations—Legionnaires’ disease and Pontiac fever—are contrasted in terms of severity, systemic involvement, and treatment needs. Diagnostic methods include culture, urinary antigen testing, and serology. Management involves macrolides, doxycycline, or fluoroquinolones, with rifampicin added if symptoms persist. The chapter also highlights prevention strategies, public health reporting requirements, and environmental control of water systems. All of the information maps to the RCEM Basic Sciences syllabus, making it relevant to Emergency Medicine practice and the examination.