free-living amoebae they are amoebae that normally inhabit: -water (lakes, swimming pools,...
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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
Amoeboid form
Trophozoite form
Naegleria fowleri Acanthamoeba species
In water
Flagellate form
Cyst form Cyst form
Trophozoite
In water or air
Dr. RAAFAT MOHAMED
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I- Naegleria fowleri(Acute primary amoebic Meningoencephalitis)
• Geographical Distribution: some parts of the world.
• Mode of infection:
- Swimming and sniffing (inhalation) in contaminated water.
إستنشاق
Diffuse meningoencephalitis
Dr. RAAFAT MOHAMED
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Pathogenesis and Clinical Picture
Amoeboid trophozoite
Nasal mucosa
Cribriform plate
Olfactory nerve
Brain, meninges
Diffuse meningoencephalitis with haemorrhage and necrosis of brain tissue
Fever, headache, nausea, vomiting, stiffness of neck, convulsions.
Disturbance in the sense of smell and taste
Coma and death within 3-6 days from infection
Thus Naegleria causes acute fulminant rapidly fatal
disease Dr. RAAFAT MOHAMED
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Dr. RAAFAT MOHAMED
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Dr. RAAFAT MOHAMED
brain sectionin vitro culture
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Acanthamoeba species
Granulomatous Amoebic Encephalitis
Acanthamoeba Keratitis
Mode of infection
Nose to Lower respiratory tract to Blood to Brain
Ulcerated skin and mucosa to Blood to Brain
Through corneal traumaExposure to contaminated waterWearing contaminated contact lenses
Dr. RAAFAT MOHAMED
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Dr. RAAFAT MOHAMED
Cyst
Trophozoite
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Dr. RAAFAT MOHAMED
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Pathogenesis and Clinical Picture
Acanthamoeba causes single or multiple focal granulomatous space-occupying lesions
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
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• 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
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Diagnosis
• 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
Naegleria Acanthamoeba
Dr. RAAFAT MOHAMED
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Treatment
No complete satisfactory treatment
Naegleria Acanthamoeba
Amphotericin BExcision of the focal lesion
+ ketoconazol
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
(I.V. or I. thecal)
Dr. RAAFAT MOHAMED
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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
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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