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. 1991 Nov;57(11):3187–3192. doi: 10.1128/aem.57.11.3187-3192.1991

Comparison of animal infectivity, excystation, and fluorogenic dye as measures of Giardia muris cyst inactivation by ozone.

C W Labatiuk 1, F W Schaefer 3rd 1, G R Finch 1, M Belosevic 1
PMCID: PMC183946  PMID: 1723584

Abstract

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, 22 degrees C) in ozone-demand-free phosphate buffer. There was a significant difference between fluorogenic staining and infectivity (P less than or equal to 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 less than or equal to 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.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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