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14 3 Amoebae
Treatment
The drug of choice is intravenous amphotericin B (1.5 mg/kg/day in 2 divided doses
for 3 days followed by 1 mg/kg/day once daily for 11 days). It can also be given
intrathecally. Treatment combining miconazole and sulfadiazine has shown limited
success. Majority of cases are fatal despite treatment.
Prevention and Control
1. Chlorination of swimming pools
Acanthamoeba Species
Acanthamoeba culbertsoni is the species most often responsible for human infec-
tion. Other species like A. polyphaga, A. castellanii, and A. astronyxis have also
been reported.
Distribution
It is an opportunistic pathogen found worldwide in the environment, water and soil.
Habitat
In human, it is found in the CNS and eye.
Morphology
It occurs in 2 forms:
1. Trophozoite
2. Cyst (Fig. 3.6)
Trophozoite measures 20–50 μm in size and is characterized by spine-like pseu-
dopodia (acanthopodia). It does not have a flagellate stage. The cyst has a polygonal
double walled and is highly resistant. It measures 10–20 μm. Cyst is found in brain
tissue.
