Isolation and concentration of Cryptosporidium from water

Abstract

A method was developed for the concentration and detection of Cryotosooridium oocysts in water. Oocysts were concentrated from 100 gallon volumes of tapwater using spun polypropylene cartridge filters. The filter was backflushed and washed with 0.1% Tween 80 in deionized water. Centrifugation of the eluate resulted in a suspension containing both oocysts and sediment. Density gradient centrifugation was used to remove the sediment. Membrane filtration of the final suspension was followed by labelling the oocysts with a fluorescein linked monoclonal antibody. Enumeration of the oocysts was accomplished by fluorescence microscopic observation of the membrane filter. The recovery efficiency using this technique averaged 51%. Furthermore, the detection of as few as one oocyst per gallon of water was possible. This method can now be used for the investigation of waterborne outbreaks and to study the occurrence of Cryotosooridium in water.