Acanthamoeba species (spp.) are opportunistic pathogens and they are a member of free-living
amoebae (FLA). They cause granulomatous amoebic encephalitis (GAE), a chronic disease of 
immunocompromised hosts such as acquired immune-deficiency syndrome (AIDS) patients and 
transplant recipients. The present study was conducted to isolate and to identify Acanthamoeba spp.
from various water sources. During the study period, 150 water samples were collected from various 
sources such as streams and ponds, tap water, tanks, swimming pools and Nile River water. All 
samples were processed and cultured on non-nutrient agar medium (NNA) with Escherichia coli 
overlay for the isolation of Acanthamoeba spp. Organism identifying was based on the microscopic 
morphology of cyst and trophozoites forms. Confirmation PCR was done to positive culture samples.
The pathogenicity of Acanthamoeba spp. was analyzed by thermo-tolerance assay. Acanthamoeba 
spp. were detected in 84 (56%) out of the 150 examined water samples. The highest percentage of 
Acanthamoeba presence was observed in streams and ponds water (70.73%), followed by swimming 
pools water samples (60%) and Nile River water samples (66.67%) and the lowest was in tap water 
samples (37.5%). Out of 84 water samples positive by NNA culture, 72 (85.71%) samples were 
positive by PCR using specific primers for Acanthamoeba spp. Based on pathogenicity test assays, 
among 84 positive cultures, 39 (46.43%) were thermo-tolerant. This study was showing the 
distribution of Acanthamoeba spp. in various water sources in the environment. Also, this study
confirmed that the high presence of pathogenic strains in recreational water could threat contact lens 
wearers.