Hostname: page-component-5d59c44645-n6p7q Total loading time: 0 Render date: 2024-02-25T10:48:26.867Z Has data issue: false hasContentIssue false

In vitro excystation of Cryptosporidium parvum

Published online by Cambridge University Press:  06 April 2009

L. J. Robertson
Scottish Parasite Diagnostic Laboratory, Stobhill General Hospital, Springburn, Glasgow G21 3UW, Scotland
A. T. Campbell
Scottish Parasite Diagnostic Laboratory, Stobhill General Hospital, Springburn, Glasgow G21 3UW, Scotland
H. V. Smith*
Scottish Parasite Diagnostic Laboratory, Stobhill General Hospital, Springburn, Glasgow G21 3UW, Scotland
*Reprint requests to Dr H. V. Smith.


Protocols for in vitro excystation of oocysts of Cryptosporidium parvum, including different chemical pre-incubation steps, were compared to examine some of the biochemical triggers involved in excystation and to define an in vitro excystation protocol of a reproducibly high efficiency. Pre-incubation steps which increased the permeability of the oocysts were found to enhance excystation dynamics and pre-treatment of oocysts with saliva was found to decrease the permeability and reduce excystation. Although excystation was maximal after incubation for 4 h, sporozoites tended to lyse over this period, and maximum sporozoite recovery occurred after 30 min. The results obtained are discussed in relation to excystation protocols adopted by different research groups and a number of recommendations are given for in vitro excystation of C. parvum oocysts.

Research Article
Copyright © Cambridge University Press 1993

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)



Blewett, D. A. (1989). Disinfection and oocysts. In Cryptosporidium. Proceedings of the First International Workshop (ed. Angus, K. W.&Blewett, D. A.), pp. 107–16. Edinburgh: The Animal Disease Research Association.Google Scholar
Campbell, A. T., Robertson, L. J. & Smith, H. V. (1992). Viability of Cryptosporidium parvum oocysts: correlation of in vitro excystation with inclusion or exclusion of fluorogenic vital dyes. Applied and Environmental Microbiology 58 (in the Press).Google Scholar
Current, W. L. (1990). Techniques and laboratory maintenance of Cryptosporidium. In Cryptosporidiosis of Man and Animals (ed. Dubey, J. P., Speer, C. A. & Fayer, R.), pp. 3150. Boca Raton, Florida: CRC Press.Google Scholar
Fayer, R. & Leek, R. G. (1984). The effect of reducing conditions, medium, pH, temperature and time on in vitro excystation of Cryptosporidium. Journal of Protozoology 31, 567–9.Google Scholar
Hibbert, L. E. & Hammond, D. M. (1968). Effects of temperature on in vitro excystation of various Eimeria species. Experimental Parasitology 23, 161–70.Google Scholar
Jackson, A. R. B. (1962). Excystation of Eimeria arlongi (Marotel, 1905): stimuli from the host sheep. Nature, London 194, 847–9.Google Scholar
Nyberg, J. & Hammond, D. M. (1964). Excystation of Eimeria bovis and other species of bovine coccidia. Journal of Protozoology 11, 474–80.Google Scholar
Reduker, D. W. & Speer, C. A. (1985). Factors influencing excystation in Cryptosporidium oocysts from cattle. Journal of Parasitology 71, 112–15.Google Scholar
Reduker, D. W., Speer, C. A. & Blixt, J. A. (1985). Ultrastructural changes in the oocyst wall during excystation of Cryptosporidium parvum (Apicomplexa; Eucoccidiorida). Canadian Journal of Zoology 63, 1892–6.Google Scholar
Smith, H. V., Smith, A. L. & Girdwood, R. W. A. (1988). The effect of free chlorine on the viability of Cryptosporidium spp. oocysts. WRC Publication PRU 2023-M. Water Research Centre.Google Scholar
Sundermann, C. A., Lindsay, D. S. & Blagburn, B. L. (1987). In vitro excystation of Cryptosporidium baileyi from chickens. Journal of Protozoology 34, 2830.Google Scholar
Woodmansee, D. B. (1987). Studies of in vitro excystation of Cryptosporidium parvum from calves. Journal of Protozoology 34, 398402.Google Scholar
Woodmansee, D. B. & Pohlenz, J. F. L.(1984). Development of Cryptosporidium sp. in a human rectal tumor cell line. Proceedings of the Fourth International Symposium on Neonatal Diarrhea, Veterinary Infectious Disease Organisation, Saskatchewan, pp. 306–17.Google Scholar