Discussion
In order to identify the prevalence and different genotypes of two neglected waterborne protists (Acanthamoeba and Naegleria fowleri) in water samples from various sources in Dakahlia governorate, PCR-testing in conjunction with isolate sequencing was carried out. Out of 62 protozoan-suspected samples using microscopic examination, Acanthamoeba were molecularly confirmed in 24 (38.7%) samples from various sources including tap water. In addition, Naegleria spp. were detected in 6 (9.6%) samples from the Nile, two of them (3.2%) were identified as N. fowleri. Sequencing of 20 samples of Acanthamoeba was successful; 18 were assigned the genotype T3 and two the T4. Results from the current study were integrated with those from past surveys conducted in Egypt for analysis. Acanthamoeba showed the highest mean prevalence (43.03%) with insignificant variations among various water sources. The incidence of finished water in drinking water treatment plants had lower than the raw water, but the filtration efficiency has not exceeded 60.0%. Different genotypes of Acanthamoeba were found with the T4 (the highly pathogenic type) was the most significantly identified type. A common T4 haplotype was found circulating in water from Egypt as well as 3 other countries (Tanzania, Rwanda, Uganda) located on the Nile basin. This haplotype included isolates from keratitis-infected patients, which confirms the potential role of water in the epidemiology of AK infecting humans in these countries. The Nile water has the greatest estimated mean prevalence of Naegleria spp. at 23.79%. In the current study, occurrence of potentially pathogenic protists with a neglected status, has been confirmed in water from Egypt, which should prompt the authorities to revise the protocols for controlling these pathogens in water.
Keywords: Acanthamoeba; Naegleria fowleri; Genotype; Water; the Nile; Egypt.
