First identification of Naegleria species and Vahlkampfia ciguana in Nile water, Cairo, Egypt: Seasonal morphology and phylogenetic analysis.

Background/purpose: In Egypt, there is a scarcity of data concerning Naegleria (N.) family, with a shortage of phylogenetic studies. This study's aim was molecular detection, sequencing and phylogenetic analysis of morphologically identified Nagleria and to determine natural seasonal distribution of Nagleria species in water sources of Greater Cairo, Egypt.
Methods: A total of 120 water samples were collected during each season over a year. Every water sample was filtrated and cultured on non-nutrient agar (NNA). Morphologically positive Nagleria-like isolates were subjected to Nagleria genus and species-specific PCR targeting rDNA gene, PCR products were sequenced and obtained sequences were phylogenetic analyzed.
Results: Nile River water was the only source found to contained Naegleria. For the first time in Egypt, Vahlkampfia ciguana and the Naegleria species N.australiensis, N.philippinensis and N.neojejuensis were identified from the Nile water. The pathogenic Naegleria fowleri, previously reported in Egypt, was however not detected in this study.
Conclusion: Interestingly, there were no seasonal variations in prevalence of Naegleria spp.; yet, there was seasonal diversity in the water samples of the same site. These newly discovered Vahlkampfiidae in Egyptian aquatic environments indicate the need for further phylogenetic investigations using bigger sample sizes in order to determine their potential risk for human health.
(Copyright © 2018. Published by Elsevier B.V.)