1. Potentially Pathogenic 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)
Geographical Distribution: some parts of the world.
Mode of infection:
Swimming and sniffing (inhalation) in contaminated water.
Diffuse meningoencephalitis
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

4. Dr. RAAFAT MOHAMED

5. in vitro culture brain section
Dr. RAAFAT MOHAMED

6. Granulomatous Amoebic Encephalitis Acanthamoeba Keratitis
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
Trophozoite
Dr. RAAFAT MOHAMED

8. Dr. RAAFAT MOHAMED

9. 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

10. Naegleria meningoencephalitis Acanthamoeba encephalitis
Children & young adults
Debilitated Chronically ill low immunity
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
Dr. RAAFAT MOHAMED

11. - Suspension in fresh water.
Diagnosis
Naegleria
Acanthamoeba
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
Dr. RAAFAT MOHAMED

12. No complete satisfactory treatment
Naegleria
Acanthamoeba
No complete satisfactory treatment
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. Identification of trophozoites and cysts in corneal scraping: Directly
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