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  1. Free-living Amoebae They are amoebae that normally inhabit: • Water (lakes, swimming pools, air-conditioning units) • Moist soil. • Decaying vegetations. Potentially Pathogenic Free-living amoebae Naegleria fowleri Acanthamoeba species In water In water or air Trophozoite Trophozoite form Amoeboid form Cyst form Cyst form Flagellate form Dr. RAAFAT MOHAMED

  2. I- Naegleria fowleri(Acute primary amoebic Meningoencephalitis) Diffuse meningoencephalitis • Geographical Distribution: some parts of the world. • Mode of infection: • Swimming and sniffing (inhalation) in contaminated water. إستنشاق Dr. RAAFAT MOHAMED

  3. Pathogenesis and Clinical Picture Diffuse meningoencephalitis with haemorrhage and necrosis of brain tissue Brain, meninges Fever, headache, nausea, vomiting, stiffness of neck, convulsions. Olfactory nerve Cribriform plate Disturbance in the sense of smell and taste Nasal mucosa Coma and death within 3-6 days from infection Amoeboid trophozoite Thus Naegleria causes acute fulminant rapidly fatal disease Dr. RAAFAT MOHAMED


  5. in vitro culture brain section Dr. RAAFAT MOHAMED

  6. Acanthamoeba species Granulomatous Amoebic Encephalitis Acanthamoeba Keratitis Mode of infection Nose to Lower respiratory tract to Blood to Brain Through corneal trauma Exposure to contaminated water Wearing contaminated contact lenses Ulcerated skin and mucosa to Blood to Brain Dr. RAAFAT MOHAMED

  7. Cyst Dr. RAAFAT MOHAMED Trophozoite


  9. Pathogenesis and Clinical Picture Acanthamoeba causes single or multiple focal granulomatous space-occupyinglesions in the brain. • Headache, nausea, vomiting, convulsions, stiffness of the neck and altered mental state. • Sub-acute or chronic course lasting for weeks to months or years. • In AIDS patients, the disease may be fulminating resembling infection with Naegleria Dr. RAAFAT MOHAMED

  10. Diffuse meningoencephalitis. Runs rapidly fatal course (death within 3-6 days) History of swimming in natural water or swimming pools. Infection occurs through: The nasal route cribriform plate olfactory nerve brain. Focal, granulomatous, space-occupying lesion. Runs sub-acute or chronic course (lasts for weeks, months or years) Not strongly associated with swimming. Infection occurs in: Lower respiratory tract, ulcerated skin or mucosa blood stream CNS Naegleria meningoencephalitis Acanthamoeba encephalitis Children & young adults Debilitated Chronically ill low immunity Dr. RAAFAT MOHAMED

  11. History of swimming in natural water or in swimming pools within the preceding days. C.S.F. examination: - Microscopy. - Suspension in fresh water. - Culture. C.S.F. examination Diagnosis Naegleria Acanthamoeba Dr. RAAFAT MOHAMED

  12. No complete satisfactory treatment Treatment Naegleria Acanthamoeba Excision of the focal lesion + ketoconazol Amphotericin B (I.V. or I. thecal) Penicillin and chloramphenicol Epidemiology and Control of Naegleria Water and air are sources of infection Avoidance of swimming in contaminated water Proper chlorination of water Dr. RAAFAT MOHAMED

  13. Acanthamoeba keratitis Pathogenesis and Clinical picture: Chronic progressive ulcerative keratitis perforation In AIDS patients, the infection may cause endophthalmitis. Severe ocular pain and affection of vision. Dr. RAAFAT MOHAMED

  14. Diagnosis Identification of trophozoites and cysts in corneal scraping: • Directly • After culture Treatment Oral itraconazole + topical miconazole Corneal transplant Epidemiology and Control Wearing of contact lenses especially while swimming Inappropriate care of lenses The use of home-made saline for cleaning lenses Dr. RAAFAT MOHAMED