assessment of giardia and cryptosporidium assemblages/ species and their viability in potable tap water in benisuef, 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 pcrrflp 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.