Page 15: Guidelines for Canadian Drinking Water Quality: Guideline Technical Document - Enteric Protozoa: Giardia and Cryptosporidium

Appendix E:

Selected ^{Table 1 Footnote a} Giardia and Cryptosporidium outbreaks related to public, semi-public and private drinking water systems in Canada (1977-2001)
Date	Location	Causative agent	Scope of outbreak	Attributable causes	References
Mar 20 - Apr 26, 2001	North Battleford, SK	Cryptosporidium	25 laboratory confirmed; 5,800 - 7,100 people estimated to have been affected	vulnerability of the North Battleford River to contamination by Cryptosporidium in runoff (i.e., drinking water intake only 3.5 km downsteam of the treated sewage outfall) poor treatment performance (including ineffective turbidity removal)	Stirling et al., 2001
Jun 2 - Jul 12, 1996	Cranbrook, BC	Cryptosporidium	29 laboratory-confirmed; 107 clinical; estimated 2,000 cases	livestock manure contamination of the unfiltered, chlorinated water supply	BCCDC, 1996 Ong et al., 1997, 1999
Feb - May, 1994	Temagami, ON	Giardia	26 laboratory-confirmed; between 160 and 330 clinical	contamination from human sewage, due to premature thaw in February, and waste management problems contamination from beaver poor filtration performance inadequate chlorine disinfection	Wallis et al., 1998
Feb - May, 1993	Kitchener-Waterloo, ON	Cryptosporidium	143 laboratory-confirmed	*Note: No epidemiological evidence reported to establish association with drinking water spring run-off (increased turbidity) recycling filter backwash supernatant to the filters (concentrated oocysts from raw water); challenged fine-particle removal in the treatment process	Pett et al., 1993 Welker et al., 1994
Jan - Apr, 1990	Creston & Erikson, BC	Giardia	124 laboratory-confirmed	unfiltered, unchlorinated surface water beavers excreting large numbers of Giardia cysts into water supply	Isaac-Renton et al., 1993, 1994
Jun - Aug, Nov, 1986	Penticton, BC	Giardia	362 laboratory-confirmed 3,100 estimates cases	unfiltered surface water supply using only chlorine for inactivation of Giardia	Moorehead et al., 1990
Nov - Dec, 1985	Creston, BC	Giardia	83 laboratory-confirmed	unfiltered, unchlorinated surface water	Isaac-Renton et al., 1993
Table 1 Footnotes Table 1 Footnote 1 These represent well-documented outbreaks. Return to Table 1 footnote a referrer

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Date modified:: 2013-04-17