Skip to main content


Buy Article:

$17.50 plus tax (Refund Policy)

Or sign up for a free trial


Effects of gamma irradiation on in vitro excystation of CRYPTOSPORIDIUM PARVUM oocysts were tested to elucidate requirements for inducing in vitro excystation. Gamma irradiation treatment was applied at 200 krads, 2,000 krads, and 5,000 krads. Oocysts receiving 200 krad of gamma irradiation excysted at the same rates as non-irradiated control oocysts (95%); the excystation rates were lowered (50%) by irradiation of 2,000 krads; and no excystation was observed when oocysts were irradiated with 5,000 krads. Most of the sporozoites exposed to 2,000 krads were permeable to propidium iodide (PI positive) after excystation. The dye permeability results were only slightly altered by acid pretreatment. No differences were observed between the dye permeability of untreated control oocysts and oocysts treated with 200 krads. The results suggest that live sporozoites may not be necessary for inducing excystation, although enzymes from the sporozoites (viable or not) may be required for excystation.

Document Type: Research Article


Publication date: 2000-01-01

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free ContentFree content
  • Partial Free ContentPartial Free content
  • New ContentNew content
  • Open Access ContentOpen access content
  • Partial Open Access ContentPartial Open access content
  • Subscribed ContentSubscribed content
  • Partial Subscribed ContentPartial Subscribed content
  • Free Trial ContentFree trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more