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Published on: July 3, 2015
Quantitative evaluation of infectivity change of Cryptosporidium parvum after gamma irradiation
Soo-Ung Lee1, Mikyo Joung, Taekyoung Nam
1Department of Environmental and Tropical Medicine, Konkuk University School of Medicine, Seoul, Korea.
Abstract:
Cryptosporidium parvum is a well-known waterborne and opportunistic intracellular protozoan parasite that causes diarrheal illness. In this study, we quantitatively investigated reduction of the infectivity of C. parvum after gamma irradiation and repair of the infectivity during incubation time after irradiation. C. parvum oocysts were subjected to gamma irradiation at various doses (1, 5, 10, and 25 kGy), and the in vitro infectivity was measured by real-time PCR every day up to 7 days after irradiation. The in vitro infectivity of C. parvum on human ileocecal adenocarcinoma cells (HCT-8) was effectively reduced (> 2 log(10)) by irradiation at 10 kGy or more. However, in the experiment to find out repair of the infectivity, recovery was not noted until day 7 post-incubation.
Insights
Gamma irradiation effectively reduces Cryptosporidium parvum infectivity at doses of 10 kGy or higher. No significant recovery of infectivity was observed in Cryptosporidium parvum oocysts up to 7 days post-irradiation.
Area of Science:
- Parasitology
- Radiation Biology
- Food Safety
Background:
- Cryptosporidium parvum is a significant waterborne protozoan parasite causing diarrheal diseases.
- Understanding methods to inactivate C. parvum is crucial for public health and water safety.
Purpose of the Study:
- To quantitatively assess the reduction in C. parvum infectivity following gamma irradiation.
- To investigate the potential for infectivity repair in irradiated C. parvum oocysts during incubation.
Main Methods:
- C. parvum oocysts were exposed to varying doses of gamma irradiation (1, 5, 10, 25 kGy).
- In vitro infectivity was measured daily for 7 days using real-time PCR on HCT-8 cells.
- Infectivity repair was monitored over a 7-day post-incubation period.
Main Results:
- Gamma irradiation at 10 kGy and 25 kGy significantly reduced C. parvum infectivity by over 2 log(10).
- No recovery or repair of infectivity was detected in the irradiated oocysts up to 7 days after incubation.
Conclusions:
- Gamma irradiation is an effective method for inactivating Cryptosporidium parvum oocysts.
- Irradiated C. parvum oocysts do not appear to repair or regain infectivity within 7 days post-treatment.
