Assessment of Giardia and Cryptosporidium Assemblages/Species and Their Viability in Potable Tap Water in Beni-Suef, Egypt Using Nested PCR/RFLP and Staining

Background: The protozoan Giardia and Cryptosporidium are responsible for most water-borne diseases all over the world. The extent and number of outbreaks of waterborne diseases suggests a significant risk of their potential transmission via drinking water. This study aimed to document the prevalence and viability of Giardia and Cryptosporidium (oo) cysts in tap water samples in Beni-Suef Governorate, Egypt and to detect the predominant Giardia and Cryptosporidium assemblages/species using nested PCR/Restriction Fragment Length Polymorphism (RFLP) confirmed by further sequencing of positive samples. Methods: A total of 80 tap water samples were collected throughout a year from four big centers and filtered using the membrane filtration method. Samples were stained by Lugol's iodine, Modified Zeihl-Neelsen (MZN) (to detect prevalence) and trypan blue stain (to detect viability). Nested PCR-RFLP and sequencing were used for molecular characterizations and genotyping of the detected Giardia and Cryptosporidium. Results: Giardia and Cryptosporidium DNA was detected in 20 (25%) and 29 (36.3%) samples respectively, with predominance of Giardia assemblage B (85%) and C. hominis (75.9%). The prevalence and viability of both parasites (oo) cysts showed seasonality which peaked in summer and were greater in Beba center and in rural areas. Conclusion: To our knowledge, no studies have been done in these areas before. The anthroponotic transmission has an important role in giardiasis and cryptosporidiosis epidemiology in this studied area.