Identification of Cryptosporidium oocysts in river water

Abstract

Water samples were collected from four rivers in Washington State and two rivers in California and examined for the presence of Cryptosporidium oocysts. Oocyst-sized particles were concentrated from 20-liter samples of water by membrane filtration, centrifugation, and differential sedimentation. The particle concentrate was then deposited on a 25-mm-diameter membrane filter for oocyst identification by indirect immunofluorescence assay. The identification procedure had a limit of detection of about five oocysts per liter. Cryptosporidium oocysts were found in each of 11 river water samples examined. Concentrations ranged from 2 to 112 oocysts per liter. The finding of Cryptosporidium oocysts in all samples examined from six western rivers is noteworthy in light of recent reports indicating that Cryptosporidium sp. is a significant agent of human and animal disease. This finding suggests that waterborne oocysts of this parasite are more important than was previously recognized. More detailed studies are needed to define geographical and temporal distribution, to assess the viability of waterborne oocysts, and to determine the importance of water as a means of transmission.

Impact of Riparian Zone Protection from Cattle on Nutrient, Bacteria, F-coliphage,Cryptosporidium, andGiardiaLoading of an Intermittent Stream

“…Microorganisms evaluated in this study included Cryptosporidium oocysts 2 to 5 μm (Ongerth and Stibbs, 1987), Giardia spp. cysts 6 to 16 μm (LeChevallier et al, 1991), fecal indicator bacteria (e.g., E. coli) approximately 2 μm long and 0.5 μm in diameter (Kubitschek, 1990), and viruses (e.g., F-coliphage) ~50 nm in size (Lute et al, 2004).…”

Evaluation of Cryptosporidium parvum oocyst recovery efficiencies from various filtration cartridges by electrochemiluminescence assays

“…Low level contamination of surface waters with Cryptosporidium parvum oocysts has been reported in many countries (Ongerth and Stibbs 1987;LeChevallier et al 1991), and is a potential risk to public health (Hass and Rose 1995). There have been several well-documented water-borne outbreaks of cryptosporidiosis worldwide (Haselbeck et al 1990;Richardson et al 1991;Mac Kenzie et al 1994 3 ; Atherton et al 1995).…”

Recovery of Cryptosporidium oocysts from small and large volume water samples using a compressed foam filter system

“…Currently, the most commonly employed methods for the capture and recovery of oocysts from water rely on entrapment on either a wound polypropylene cartridge filter with 1 mm nominal pore size (Musial et al 1987 ;Anon. 1990) or membrane filters (Ongerth and Stibbs 1987 ;Dawson et al 1993). Although such filters can entrap up to 98% of seeded oocysts, losses arise when the oocysts cannot be effectively recovered or eluted from the cartridge or membrane (Smith et al 1993).…”