Please note that the content of this book mainly consists of articles that are available online from Wikipedia or other free sources. Acanthamoebiasis is a globally widespread disease caused by Acanthamoebae (Acantamoeba sp.). It manifests as granulomatous amoebic encephalitis (GAE) or Acanthamoeba keratitis. The disease is triggered by Acanthamoebae entering the body through skin lesions, spreading through the bloodstream, and potentially infecting the central nervous system. There is also the possibility of the lungs being used as an entry point into the body (GAE). When the disease occurs in the eye, it is usually due to soft contact lenses contaminated with the pathogen (Acanthamoeba keratitis), often in connection with trauma and a moist environment.