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Main Title Comparison of Animal Infectivity, Excystation, and Fluorogenic Dye as Measures of 'Giardia muris' Cyst Inactivation by Ozone.
Author Labatiuk, C. W. ; Schaefer, F. W. ; Finch, G. R. ; Belosevic, M. ;
CORP Author Environmental Protection Agency, Cincinnati, OH. Risk Reduction Engineering Lab. ;Alberta Univ., Edmonton.;American Water Works Association Research Foundation, Denver, CO.;Natural Sciences and Engineering Research Council of Canada, Ottawa (Ontario).
Publisher cNov 91
Year Published 1991
Report Number EPA/600/J-91/290;
Stock Number PB92-124288
Additional Subjects Ozone ; Toxicology ; Fluorescent dyes ; Virulence ; Mice ; Animal disease models ; Fluoresceins ; Ethidium bromide ; In vitro analysis ; Reprints ; Giardia muris
Library Call Number Additional Info Location Last
NTIS  PB92-124288 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 8p
Giardia muris cyst viability after ozonation was compared by using fluorescein diacetate-ethidium bromide staining, the C3H/HeN mouse-G. muris model, and in vitro excystation. Bench-scale batch experiments were conducted under laboratory conditions (pH 6.7, 22C) in ozone-demand-free phosphate buffer. There was a significant difference between fluorogenic staining and infectivity (P = or < 0.05), with fluorogenic staining overestimating viability compared with infectivity estimates of viability. This suggests that viable cysts as indicated by fluorogenic dyes may not be able to complete the life cycle and produce an infection. No significant differences between infectivity and excystation and between fluorogenic staining and excystation (P = or < 0.05) were detected for inactivations up to 99.9%. Only animal infectivity had the sensitivity to detect inactivations greater than 99.9%. Therefore, the animal model is the best method currently available for detecting high levels of G. muris cyst inactivation. (Copyright (c) 1991, American Society for Microbiology.)