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Appl Environ Microbiol. Jan 1993; 59(1): 67–73.
PMCID: PMC202056

Waterborne Giardia cysts and Cryptosporidium oocysts in the Yukon, Canada.


Several outbreaks of waterborne giardiasis have occurred in southern Canada, but nothing has been reported from the Canadian North. The objective of this study was to collect information relevant to waterborne giardiasis and cryptosporidiosis in the Yukon including epidemiological data and analyses of water, sewage, and animal fecal samples. Remote, pristine water samples were found to be contaminated with Giardia cysts (7 of 22 or 32%) but not with Cryptosporidium oocysts. Giardia cysts were found in 21% (13 of 61) of animal scats, but no Cryptosporidium oocysts were observed (small sample size). Whitehorse's drinking water was episodically contaminated with Giardia cysts (7 of 42 or 17%) and Cryptosporidium oocysts (2 of 42 or 5%). Neither were found in Dawson City's water supply. The only water treatment in the Yukon is chlorination, but contact times and free chlorine residuals are often too low to provide adequate protection by disinfection. Raw sewage samples from the five largest population centers in the Yukon contained 26 to 3,022 Giardia cysts and 0 to 74 Cryptosporidium oocysts per liter. Treated sewage from Whitehorse contained fewer Giardia cysts but more Cryptosporidium oocysts on average. Both were detected in Lake Laberge, downstream of Whitehorse, which has a history of fecal coliform contamination. Daily monitoring of raw sewage from the suburbs of Whitehorse showed a summertime peak of Giardia cysts and occasional Cryptosporidium oocysts after springtime contamination of drinking water. Despite this evidence, epidemiological data for the Yukon showed an endemic infection rate of only 0.1% for giardiasis (cryptosporidiosis is not notifiable).(ABSTRACT TRUNCATED AT 250 WORDS)

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Selected References

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  • Arrowood MJ, Sterling CR. Isolation of Cryptosporidium oocysts and sporozoites using discontinuous sucrose and isopycnic Percoll gradients. J Parasitol. 1987 Apr;73(2):314–319. [PubMed]
  • Caprioli A, Gentile G, Baldassarri L, Bisicchia R, Romoli E, Donelli G. Cryptosporidium as a common cause of childhood diarrhoea in Italy. Epidemiol Infect. 1989 Jun;102(3):537–540. [PMC free article] [PubMed]
  • Current WL. Cryptosporidiosis. J Am Vet Med Assoc. 1985 Dec 15;187(12):1334–1338. [PubMed]
  • D'Antonio RG, Winn RE, Taylor JP, Gustafson TL, Current WL, Rhodes MM, Gary GW, Jr, Zajac RA. A waterborne outbreak of cryptosporidiosis in normal hosts. Ann Intern Med. 1985 Dec;103(6 ):886–888. [PubMed]
  • Hewlett EL, Andrews JS, Jr, Ruffier J, Schaefer FW., 3rd Experimental infection of mongrel dogs with Giardia lamblia cysts and cultured trophozoites. J Infect Dis. 1982 Jan;145(1):89–93. [PubMed]
  • Isaac-Renton JL, Fogel D, Stibbs HH, Ongerth JE. Giardia and Cryptosporidium in drinking water. Lancet. 1987 Apr 25;1(8539):973–974. [PubMed]
  • LeChevallier MW, Norton WD, Lee RG. Occurrence of Giardia and Cryptosporidium spp. in surface water supplies. Appl Environ Microbiol. 1991 Sep;57(9):2610–2616. [PMC free article] [PubMed]
  • Shahid NS, Rahman AS, Sanyal SC. Cryptosporidium as a pathogen for diarrhoea in Bangladesh. Trop Geogr Med. 1987 Jul;39(3):265–270. [PubMed]
  • Ongerth JE, Stibbs HH. Identification of Cryptosporidium oocysts in river water. Appl Environ Microbiol. 1987 Apr;53(4):672–676. [PMC free article] [PubMed]
  • Roberts-Thomson IC, Stevens DP, Mahmoud AA, Warren KS. Giardiasis in the mouse: an animal model. Gastroenterology. 1976 Jul;71(1):57–61. [PubMed]
  • Tzipori S. Cryptosporidiosis in animals and humans. Microbiol Rev. 1983 Mar;47(1):84–96. [PMC free article] [PubMed]

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