Abstract
Bovine fecal samples (1 g) negative for Cryptosporidium sp. oocysts were seeded with 7 x 10(4) Cryptosporidium parvum oocysts and purified by either water-ether concentration, sucrose density flotation, or zinc sulfate flotation to evaluate oocyst recovery. The effect of these purification techniques on the viability of recovered oocysts was also evaluated. Significantly higher numbers of seeded oocysts were recovered by water-ether concentration (recovery rate, 46 to 75%) than by sucrose density (24 to 65%) or zinc sulfate (22 to 41%) flotation methods. In addition, water-ether concentration did not exert a significant effect on the viability of the population of oocysts recovered, whereas sucrose density flotation and zinc sulfate flotation selectively concentrated viable oocysts. The water-ether concentration procedure is recommended for use in epidemiological studies in which both oocyst enumeration and viability assessment are required.
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- Allen A. V., Ridley D. S. Further observations on the formol-ether concentration technique for faecal parasites. J Clin Pathol. 1970 Sep;23(6):545–546. doi: 10.1136/jcp.23.6.545. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Campbell A. T., Robertson L. J., Smith H. V. Viability of Cryptosporidium parvum oocysts: correlation of in vitro excystation with inclusion or exclusion of fluorogenic vital dyes. Appl Environ Microbiol. 1992 Nov;58(11):3488–3493. doi: 10.1128/aem.58.11.3488-3493.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Current W. L., Long P. L. Development of human and calf Cryptosporidium in chicken embryos. J Infect Dis. 1983 Dec;148(6):1108–1113. doi: 10.1093/infdis/148.6.1108. [DOI] [PubMed] [Google Scholar]
- Garcia L. S., Bruckner D. A., Brewer T. C., Shimizu R. Y. Techniques for the recovery and identification of Cryptosporidium oocysts from stool specimens. J Clin Microbiol. 1983 Jul;18(1):185–190. doi: 10.1128/jcm.18.1.185-190.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LeChevallier M. W., Norton W. D., Siegel J. E., Abbaszadegan M. Evaluation of the immunofluorescence procedure for detection of Giardia cysts and Cryptosporidium oocysts in water. Appl Environ Microbiol. 1995 Feb;61(2):690–697. doi: 10.1128/aem.61.2.690-697.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mtambo M. M., Nash A. S., Blewett D. A., Wright S. Comparison of staining and concentration techniques for detection of Cryptosporidium oocysts in cat faecal specimens. Vet Parasitol. 1992 Dec;45(1-2):49–57. doi: 10.1016/0304-4017(92)90026-6. [DOI] [PubMed] [Google Scholar]
- Robertson L. J., Campbell A. T., Smith H. V. In vitro excystation of Cryptosporidium parvum. Parasitology. 1993 Jan;106(Pt 1):13–19. doi: 10.1017/s003118200007476x. [DOI] [PubMed] [Google Scholar]
- Waldman E., Tzipori S., Forsyth J. R. Separation of Cryptosporidium species oocysts from feces by using a percoll discontinuous density gradient. J Clin Microbiol. 1986 Jan;23(1):199–200. doi: 10.1128/jcm.23.1.199-200.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weber R., Bryan R. T., Bishop H. S., Wahlquist S. P., Sullivan J. J., Juranek D. D. Threshold of detection of Cryptosporidium oocysts in human stool specimens: evidence for low sensitivity of current diagnostic methods. J Clin Microbiol. 1991 Jul;29(7):1323–1327. doi: 10.1128/jcm.29.7.1323-1327.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weber R., Bryan R. T., Juranek D. D. Improved stool concentration procedure for detection of Cryptosporidium oocysts in fecal specimens. J Clin Microbiol. 1992 Nov;30(11):2869–2873. doi: 10.1128/jcm.30.11.2869-2873.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]