ABSTRACT
Parasites in fi nished water, if left undetected, can detrimentally impact both public safety and economy. Cryptosporidium parvum is a common parasitic protozoan responsible for numerous waterborne and foodborne outbreaks of diarrheal disease, causing a majority of gastrointestinal parasitic infections globally (Fayer et al. 2000). In the United States alone, an estimated 300,000 cases of cryptosporidiosis occur each year causing 66 deaths (Mead et al. 1999). Median infective dose is estimated as 87 oocysts for the Iowa calf isolates (Okhuysen et al. 1999). Oocysts have been found in surface water samples with concentrations ranging from 0.1 to 10,000 oocysts per 100 L (Lisle and Rose 1995; Mons et al. 2009). Giardia lamblia is a fl agellated enteric protozoan parasite and a causative agent of human giardiasis (Adam 2001). Infection occurs by ingestion of G. lamblia cysts present in contaminated water and food, or by fecal-oral route. Cryptosporidium and Giardia have been classifi ed as important human pathogens in the WHO Neglected Disease Initiative (Savioli et al. 2006). Since ingestion of as few as several (oo)cysts may cause cryptosporidiosis or giardiasis, there is a great need for a sensitive method for detecting and monitoring C. parvum and G. lamblia in source and fi nished water samples at ultralow concentrations.
