Morphology, life cycle, diagnosis, symptoms, and treatment.

1. Acanthamoeba
species
Prepared by: Veronica Baje

2. Acanthamoeba
species
• Acanthamoeba spp. are free-living amebae
that inhabit a variety of air, soil, and water
environments. However, these amebae can
also act as opportunistic as well as
nonopportunistic pathogens.

3. Trophozoites
• Averages 25μm, with a range of 12 to 45μm in
size.
• Motility is sluggish and there is little evidence of
progressive motility.
• Spinelike pseudopods project outward from the
base of the organism.
• Contain one nucleus, consisting of a large
karyosome similar to that of N. fowleri.

4. Cysts
• Round-shaped
• Measures 8 to 25μm.
• Double cell wall.
• Inner smooth cell wall is surrounded by an
outer jagged cell wall.
• Single nucleus.

5. Life Cycle
• Acanthamoeba has only two stages, cysts and trophozoites
• In its life cycle. No flagellated stage exists as part of the life
cycle. The trophozoites replicate by mitosis (nuclear
membrane does not remain intact).
• The trophozoites are the infective forms, although both cysts
and trophozoites gain entry into the body through various
means. Entry can occur through the eye, the nasal passages
to the lower respiratory tract, or ulcerated or broken skin.
• When Acanthamoeba spp. enters the eye it can cause severe
keratitis in otherwise healthy individuals, particularly contact
lens users .
• When it enters the respiratory system or through the skin, it
can invade the central nervous system by hematogenous
dissemination causing granulomatous amebic encephalitis
(GAE) or disseminated disease, or skin lesions in individuals
with compromised immune systems.

6. Laboratory
Diagnosis
• Specimen of choice is CSF. Brain tissue may
also be examined.

7. Clinical Symptoms
• Granulomatous amebic encephalitis:
symptoms include headaches, seizures,
stiff neck, nausea, and vomiting.
• Acanthamoeba keratitis: Severe ocular
pain and vision problems.

8. Treatment
• Because of the slow progression of GAE, most
patients who suffer from it die.
• There is some evidence to suggest that
sulfamethazine might be a suitable treatment.