Free-living amoebae
From IDWiki
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 |
- Also, Sappinia diploidea or Sappinia diploidea