AI-Herrawy A. Z.1; Mohamed S. H. 2; Ali M. 2 Mohammed A. H.2 ; Gad M. A.1*
1 Water Pollution Research Department, National research Centre; 2Ain Shams University, Egypt
Members of genus Naegleria are free-living amoebae inhabiting various aquatic environments. Some of heat-tolerant Naegleria species can provoke fatal infections in humans, and the most important source of infection is through enforced inhalation of water containing these species of Naegleria. Methods: A total of 192 water samples were collected from the river Nile, tap water, ground water and swimming pools. Samples were examined for detection of Naegleria species by cultivation on non-nutrient agar at 30oC and 45oC. Naegleria were identified based on trophozoite and cyst morphology, flagellation test and heat tolerance test. Results: Members of genus Naegleria were detected in 38.0% and 18.8 % of 192 cultured water samples at 30ͦC and 45ͦC, respectively. The highest occurrence of Naegleria grown at 30 ͦC was recorded in Nile water (70.8%), followed by 31.3% in ground water and 25% in each of tap water and swimming pool samples. On the other hand, the highest occurrence of Naegleria grown at 45 ͦC was recorded in Nile water (41.7%), followed by 16.7, 10.4 and 6.3% in ground water, swimming pools and tap water, respectively. Concerning seasonal variations, the greatest percentage of recovery of Naegleria (cultured at 45°C) occurred during summer in tap water and swimming pools, during autumn in ground water, during spring and summer in Nile river. The greatest percentage of recovery of Naegleria (cultured at 30°C) occurred during autumn and winter in Nile river, during autumn in tap water, during autumn, winter and summer in ground water, during the summer in swimming pools. Conclusion: The presence of heat-tolerant Naegleria species in Egyptian aquatic environment should be considered a potential health threat.
Keywords: Naegleria – Egyptian aquatic environment