Cryptosporidium spp. and Giar-dia intestinaiis are well-known waterborne pathogens that have caused disease outbreaks around the globe. The 1993 outbreak of cryptosporidiosis in Milwaukee and subsequent outbreaks have stimulated research regarding the occurrence and behavior of these pathogens in natural waters. Substantial research efforts have been expended to identify factors related to pathogen levels in water supplies and to identify problematic aspects of traditional water treatment and handling. ' Another research focus has been the development of improved sample collection methods and laboratory techniques for the recovery and detection of Cryptosporidium and Giardia.
Method 1623 - General
This technical document summarizes the development of USEPA Method 1623 and presents options for the simultaneous detection of Cryptosporidium and Gi-ardia (Method 1622 detects only Cryptosporidium).
Methods 1622 3 were developed to address some of the limitations of the Information Collection Rule (ICR) Protozoa Method that have been identified by various researchers.2*2,6 For improved detection and enumeration of Cryptosporidium and Giardia, Method 1623 in-corporates filtration, immu-nomagnetic separation (IMS) and immunofluorescence assay (FA) microscopy. * Organisms are confirmed using 4.6-diamidino-2 -phenylindole (DAPI) vital dye staining and differential interference contrast (DIC) microscopy.
USEPA Method 1623 and 1623.1