Send to

Choose Destination
Gastrointest Endosc. 1999 May;49(5):605-11.

Inactivation of Cryptosporidium parvum oocyst infectivity by disinfection and sterilization processes.

Author information

Division of Infectious Diseases, UNC School of Medicine, Chapel Hill, NC 27599-7030, USA.



Cryptosporidium parvum is a common cause of self-limited gastroenteritis in the normal host but may cause severe disease in immunocompromised persons. Person-to-person transmission has been well documented in households, child care centers, and hospitals. Because contaminated environmental surfaces and medical devices such as endoscopes may play a role in disease transmission, we studied the susceptibility of C parvum to chemical agents commonly used for disinfection and evaluated the efficacy of sterilization processes.


Seven disinfectants were studied at their use dilution using a suspension test. Antimicrobial activity was assessed with the use of a cell infectivity assay.


All sterilization processes tested (steam, ethylene oxide, Sterrad 100) inactivated 3 logs or greater of C parvum. The only liquid disinfectant/sterilant able to inactivate greater than 3 logs of C parvum was 6% and 7.5% hydrogen peroxide. Agents that did not completely inactivate C parvum included hydrogen peroxide at lower concentrations or exposure times, peracetic acid, sodium hypochlorite, a phenolic, a quaternary ammonium compound, 2% glutaraldehyde, and ortho-phthalaldehyde.


Most high-level disinfectants used on endoscopes have limited efficacy against C parvum. However, the infectivity of C parvum on dry surfaces decreases rapidly. Therefore, current cleaning and high-level disinfection guidelines are adequate to prevent nosocomial transmission of C parvum by means of endoscopes.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center