Free-living amoebae

	Naegleria fowleri	Acanthamoeba	Balamuthia mandrillaris
Route	Essentially direct inoculation of brain via nasal passages	Inoculation into skin or lung, then disseminates hematogenously with brain tropism
Clinical presentation	Primary amoebic meningoencephalitis (PAM), with fulminant disease within days and death within 1-2 weeks	Granulomatous amoebic encephalitis (GAE), with subacute presentations followed by fatal acute stage; may have cutaneous or sinus lesions; amebic keratitis	GAE as well, similarly subacute; may have skin lesions
Risk factors	Immunocompetent children or young adults with recreational warm fresh-water exposure	Immunocompromised people; contact lens wearers, for keratitis	Immunocompromised people, but also immunocompetent children and elderly, and Hispanics
Epidemiology	Worldwide, warm freshwater up to 45ºC (includes hot springs)	Worldwide in water and soil	Worldwide in water and soil, more cases in South America and US
Neuroimaging	Nonspecific	Space-occupying or ring-enhancing lesion (GAE)	Space-occupying or ring-enhancing lesion
Diagnosis	CSF wet mount or PCR	Cysts in brain biopsy, immunostaining or PCR; trophozoites or cysts on corneal scraping	Cysts in brain biopsy, immunostaining or PCR
Treatment	Intrathecal and intravenous amphotericin B, azoles, rifampin, miltefosine	Pentamidine, azoles, flucytosine, sulfadiazine, miltefosine, amikacin, voriconazole	Pentamidine, azithromcin, fluconazole, sulfadiazine, flucytosine, miltefosine