Inactivation of Cryptosporidium parvum oocyst infectivity by disinfection and sterilization processes

Gastrointest Endosc. 1999 May;49(5):605-11. doi: 10.1016/s0016-5107(99)70389-5.


Background: 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.

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

Results: 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.

Conclusions: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Cattle
  • Cells, Cultured
  • Cryptosporidium parvum / drug effects
  • Cryptosporidium parvum / isolation & purification
  • Cryptosporidium parvum / pathogenicity*
  • Disinfectants / pharmacology
  • Disinfection / methods*
  • Disinfection / statistics & numerical data
  • Dogs
  • Dose-Response Relationship, Drug
  • Feces / parasitology
  • Kidney / cytology
  • Kidney / parasitology
  • Linear Models
  • Steam
  • Sterilization / instrumentation
  • Sterilization / methods*
  • Sterilization / statistics & numerical data
  • Time Factors


  • Disinfectants
  • Steam