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. 1991 Sep;57(9):2610-6.
doi: 10.1128/aem.57.9.2610-2616.1991.

Occurrence of Giardia and Cryptosporidium spp. in surface water supplies

M W LeChevallier  1 , W D Norton, R G Lee
Affiliations

Occurrence of Giardia and Cryptosporidium spp. in surface water supplies

M W LeChevallier et al. Appl Environ Microbiol. 1991 Sep.

Erratum in

  • Appl Environ Microbiol 1992 Feb;58(2):780

Abstract

Giardia and Cryptosporidium levels were determined by using a combined immunofluorescence test for source waters of 66 surface water treatment plants in 14 states and 1 Canadian province. The results showed that cysts and oocysts were widely dispersed in the aquatic environment. Giardia spp. were detected in 81% of the raw water samples. Cryptosporidium spp. were found in 87% of the raw water locations. Overall, Giardia or Cryptosporidium spp. were detected in 97% of the raw water samples. Higher cyst and oocyst densities were associated with source waters receiving industrial or sewage effluents. Significant correlations were found between Giardia and Cryptosporidium densities and raw water quality parameters such as turbidity and total and fecal coliform levels. Statistical modeling suggests that cyst and oocyst densities could be predicted on the basis of watershed and water quality characteristics. The occurrence of high levels of Giardia cysts in raw water samples may require water utilities to apply treatment beyond that outlined in the Surface Water Treatment Rule of the U.S. Environmental Protection Agency.

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References

    1. J Parasitol. 1987 Aug;73(4):723-9 - PubMed
    1. Epidemiol Infect. 1989 Dec;103(3):703-15 - PubMed
    1. N Engl J Med. 1989 May 25;320(21):1372-6 - PubMed
    1. Appl Environ Microbiol. 1987 Apr;53(4):672-6 - PubMed
    1. Appl Environ Microbiol. 1985 Dec;50(6):1434-8 - PubMed

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