Occurrence of Cryptosporidium oocysts in sewage effluents and selected surface waters.

M. S. Madore, J. B. Rose, C. P. Gerba, M. J. Arrowood, C. R. Sterling

Research output: Contribution to journalArticlepeer-review

122 Scopus citations


An existing method for the detection of Cryptosporidium oocysts in water was modified to investigate oocyst prevalence in large volumes of water. Surface waters and sewage effluents were filtered, eluted from the filter, and concentrated using centrifugation. The resultant pellet was then homogenized, sonicated, and placed on a sucrose gradient to separate oocysts from the sediment. The uppermost gradient layer was then examined by immunofluorescence using a labeled monoclonal antibody. Using this technique, average numbers of oocysts detected in raw and treated sewage were 5.18 X 10(3) and 1.30 X 10(3)/L, respectively. Filtered sewage effluents had significantly lower numbers of oocysts (10.0/L). These data show that sand filtration may reduce the concentrations of this parasite in waste waters. Highly variable oocyst numbers were encountered in surface waters. Since Cryptosporidium oocysts are frequently present in environmental waters, they could be responsible for waterborne outbreaks of disease.

Original languageEnglish (US)
Pages (from-to)702-705
Number of pages4
JournalThe Journal of parasitology
Issue number4
StatePublished - Aug 1987

ASJC Scopus subject areas

  • Parasitology
  • Ecology, Evolution, Behavior and Systematics


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