Cryptosporidium Oocysts In Water Research Articles

Evaluation of different filtration techniques for the concentration of Cryptosporidium oocysts from water

The relative performances of different filter matrices were assessed for the concentration of Cryptosporidium oocysts in water. Cartridge filtration methods were examined and compared with membrane filtration and a flocculation method using seeded tap and river water to determine the most efficient and consistent method of sample concentration. From IOL samples, calcium carbonate flocculation gave the most consistently high recovery rate of Cryptosporidium oocysts (tap water mean 72.9%; river water mean 41.9%), followed by membrane filtration using 1.2µm cellulose acetate membranes (tap water mean 37.8%; river water mean 26.6%). For filtration of larger volumes (>100L) of water the Cuno Microwynd II cartridge filter provided the highest recovery rate of oocysts (tap water mean 13.3%; river water mean 10.8%) when compared with the Vokes cartridge and Balston filters. All recoveries fell dramatically when sucrose flotation techniques were applied.

Detection and occurrence of waterborne bacterial and viral pathogens

Detection and occurrence of waterborne bacterial and viral pathogens

Cryptosporidium oocysts in water for human consumption

A study was carried out on the presence of oocysts of Cryptosporidium spp. in water for human consumption in the Province of Salamanca, Spain, using four different staining techniques: Ziehl-Neelsen, auramine, indirect immunofluorescence with monoclonal antibodies (Meridian, USA) and direct immunofluorescence with monoclonal antibodies (Pasteur, France). The presence of oocysts was detected in the water used for the washing of sand filters in the four water purifying plants and in the drinking water of two of the six geographical areas studied. The Ziehl-Neelsen and auramine staining techniques were found to have excellent diagnostic correlation. Immunofluorescence stainings with monoclonal antibodies proved to be less sensitive.

Taking the eye strain out of environmental cryptosporidium analysis

The use of flow cytometry to detect Cryptosporidium oocysts in water was investigated using a Skatron Argos 100–5 instrument. Raw and treated drinking water samples seeded with oocysts and treated sewage samples known to contain oocysts were analysed by flow cytometry and by fluorescent microscopy. Oocysts could be rapidly detected in the treated sewage in raw and treated drinking water when the latter were seeded with levels of 1000 oocysts/1 or higher. Flow cytometry proved to be easier and quicker than fluorescent microscopy but an improvement in sensitivity is necessary before flow cytometery can be used for routine monitoring of drinking water supplies.

Occurrence of Cryptosporidium Oocysts in Sewage Effluents and Selected Surface Waters

An existing method for the detection of Cryptosporidium oocysts in water was modified to investigate oocyst prevalence in large volumes of water. Surface waters and sewage effluents were filtered, eluted from the filter, and concentrated using centrifugation. The resultant pellet was then homogenized, sonicated, and placed on a sucrose gradient to separate oocysts from the sediment. The uppermost gradient layer was then examined by immunofluorescence using a labeled monoclonal antibody. Using this technique, average numbers of oocysts detected in raw and treated sewage were 5.18 X 10(3) and 1.30 X 10(3)/L, respectively. Filtered sewage effluents had significantly lower numbers of oocysts (10.0/L). These data show that sand filtration may reduce the concentrations of this parasite in waste waters. Highly variable oocyst numbers were encountered in surface waters. Since Cryptosporidium oocysts are frequently present in environmental waters, they could be responsible for waterborne outbreaks of disease.

Detection of Cryptosporidium in water by using polypropylene cartridge filters.

Members of the genus Cryptosporidium are protozoan parasites that cause gastroenteritis in humans and animals and appear to be spread largely by the fecal-oral route. A method was developed for the concentration and detection of Cryptosporidium oocysts in water to assess their occurrence in the environment and potential for waterborne disease transmission. This method was developed by using spun polypropylene cartridge filters. Optimal conditions for concentration, filter elution, filter porosity, and detection were determined. Fluoresceinated monoclonal antibodies were used for oocyst detection. Experiments also were conducted to study the effect of flow rate, low oocyst numbers, and the addition of detergents on recovery and retention of oocysts. The method that was developed was sensitive enough to detect oocysts at levels of less than 1 per liter. Using this method, we isolated Cryptosporidium oocysts from secondarily treated sewage.

Detection of Cryptosporidium from Wastewater and Freshwater Environments

Cryptosporidium is a coccidian protozoan and has recently been recognized as a cause of human gastroenteritis. The illness may be severe in immunocom-promised individuals and can result in death. The organism is monoxenous, and infective oocysts are shed in the feces, which are transmitted via the fecal-oral route. Therefore, Cryptosporidium may be a possible candidate as an etiological agent of waterborne or foodborne disease. Previously, the lack of methods for detection of this organism in diarrheal samples as well as environmental samples, has made it difficult to substantiate this premise. Detection of Cryptosporidium oocysts in water has now been accomplished using a filtration-elution procedure. A fluorescently-labelled monoclonal antibody which has been used for the detection of Cryptospori di urn in feces was also used to detect the oocysts in environmental samples. The method developed for detection of Cryptosporidium in water including: 1) filtration with polypropylene cartridge filters, 2) elution with Tween 80/detergent, 3) concentration with Sheather's flotation, and 4) detection on membrane filters, was evaluated and used to examine wastewater and fresh water for Cryptosporidiurn oocyst concentrations. Recovery from the sucrose gradient step averaged 72 – 82%. Overall recovery efficiencies ranged from 25 – 82% (average 50%), but were diminished with low seeds. Concentrations were found in ranges from 60 to 52,000 oocysts/gal in treated and raw sewage. In fresh water, oocysts numbered 8 to 22,000/gal and were concentrated in rapid sand filters averaging 59,000/gal in the backflush. Cryptosporidium may now be considered a potential waterborne parasite.