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
Cryptosporidium parvum and Cyclospora cayetanensis: a review of laboratory methods for detection of these waterborne parasites.
TL;DR: An overview of the conventional and more novel techniques that are currently available to detect Cryptosporidium and Cyclospora in water is presented.
Journal ArticleDOI
Risk factors for sporadic giardiasis: a case-control study in southwestern England.
James M. Stuart,Orr H,Fiona G Warburton,Sugarthinny Jeyakanth,Carolyn Pugh,Ian Morris,Joyshri Sarangi,Gordon Nichols +7 more
TL;DR: Although case-control studies are prone to bias and the risk of Giardia infection is minimized by water treatment processes, the possibility that treated tap water is a source of sporadic giardiasis warrants further investigation.
of Flow Cytometric Methods for the Routine Detection of Cryptosporidium and Giardia in Water
Graham Vesey,Primrose Hutton,Alan Champion,Nicholas John Ashbolt,Keith Leslie Williams,Andrzej Warton,D.A. Veal +6 more
TL;DR: In this article, an alternative technique using flocculation concentra- tion, followed by flow cytometry with flu- orescence activatedcell sorting, was described, and the technique was found to be significantly more sensitive and considerably faster than the conventional methods.
Journal ArticleDOI
Review of two decades of progress in the development of management options for reducing or eradicating phytoplankton, zooplankton and bacteria in ship's ballast water
TL;DR: No single treatment option has proved to be universally effective and increasing attention has focused on multi- component treatment systems, but effective eliminating the risk of ballast water mediated invasions still remains a monumental technological and economical challenge.
Journal ArticleDOI
Efficacy of UV irradiation in inactivating Cryptosporidium parvum oocysts.
Shigemitsu Morita,Atsushi Namikoshi,Tsuyoshi Hirata,Kumiko Oguma,Hiroyuki Katayama,Shinichiro Ohgaki,Nobuyuki Motoyama,Masahiro Fujiwara +7 more
TL;DR: The results showed that for every 10°C reduction in water temperature, the increase in the UV irradiation dose required for a 2-log10 reduction in infectivity was only 7%, and forevery 10-fold increase in intensity, the dose increase was only 8%.
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.