Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability.
TLDR
The data indicate that C. parvum oocysts are 30 times moreresistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions.Abstract:
Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 times more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water.read more
Citations
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Journal ArticleDOI
Detection of Infectious Cryptosporidium Oocysts by Cell Culture Immunofluorescence Assay: Applicability to Environmental Samples
TL;DR: Cell culture immunofluorescence assays were evaluated for determination of oocyst infectivity in naturally contaminated water samples and demonstrated that surrogate methods overestimate the number of infectious oocysts and therefore the risk of infection with Cryptosporidium.
Journal ArticleDOI
Aged HCT-8 cell monolayers support Cryptosporidium parvum infection.
TL;DR: Results suggest that it may be possible to use cell monolayers from freshly confluent to 3 weeks old on hand for infectivity assays without having to schedule sample processing to coincide with development of freshlyconfluent monolayer.
Journal ArticleDOI
Multiple risk factors associated with a large statewide increase in cryptosporidiosis.
Amy L. Valderrama,Michele C. Hlavsa,Alicia Cronquist,Shaun Cosgrove,Stephanie P. Johnston,Jacquelin M. Roberts,Matthew L. Stock,Lihua Xiao,Karen Xavier,Michael J. Beach +9 more
TL;DR: The need for public health education efforts that address the multiple transmission routes for Cryptosporidium and appropriate prevention measures to avoid future transmission is emphasized.
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Sequential inactivation of Cryptosporidium parvum using ozone and chlorine.
TL;DR: Temperature was critical for both single and sequential inactivation, and the efficacy of free chlorine after 1.6 log-units of ozone primary inactivation decreased by a factor of 1.8 for every 10 degrees C temperature decrease.
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Drivers of Microbial Risk for Direct Potable Reuse and de Facto Reuse Treatment Schemes: The Impacts of Source Water Quality and Blending.
TL;DR: It is demonstrated that de facto reuse by itself, or as an input into DPR, drives microbial risks more so than the advanced-treated DPR water.
References
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Book
Standard methods for the examination of water and wastewater
TL;DR: The most widely read reference in the water industry, Water Industry Reference as discussed by the authors, is a comprehensive reference tool for water analysis methods that covers all aspects of USEPA-approved water analysis.
Journal ArticleDOI
Determination of ozone in water by the indigo method
TL;DR: In this article, the decolorization of indigo trisulfonate (600 nm, pH below 4) was used to determine the concentration of aqueous ozone in the range 0.005 −30 mg 1−1.
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Acute enterocolitis in a human being infected with the protozoan Cryptosporidium.
TL;DR: It is suggested, on the basis of the severity of the clinical symptoms, and on the pathological changes in the rectum, that the organism in this case is likely to have been the cause of the enterocolitis and thus to have was a pathogen rather than a commensal.
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Isolation of Cryptosporidium oocysts and sporozoites using discontinuous sucrose and isopycnic Percoll gradients.
TL;DR: Techniques for the large-scale isolation of Cryptosporidium oocysts and sporozoites, obtained from the feces of experimentally infected Holstein calves, were developed employing discontinuous sucrose gradients and isopycnic Percoll gradients.
Journal ArticleDOI
Large Community Outbreak of Cryptosporidiosis Due to Contamination of a Filtered Public Water Supply
Edward B. Hayes,Thomas Matte,Thomas R. O'Brien,Thomas W. McKinley,Gary S. Logsdon,Joan B. Rose,Beth L. P. Ungar,David M. Word,Margaret A. Wilson,Earl G. Long,Eugene S. Hurwitz,Dennis D. Juranek +11 more
TL;DR: Current standards for the treatment of public water supplies may not prevent the contamination of drinking water by Cryptosporidium, with consequent outbreaks of cryptosporidiosis, it is concluded.