Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: October 31, 2001
Publication Date: November 5, 2001
Citation: Niemira, B.A., Thayer, D.W. 2001. Cyclospora cayetanensis: research methodology and control by irradiation. Report of First FAO/IAEA Research CO-Ordination Meeting, November 5-9, 2001, Rio de Janeiro, Brasil. p. 1-7. Technical Abstract: Enteric coccidia such as Cyclospora or Cryptosporidium can be contaminants of fruits and vegetables. Research into applicability of irradiation as a control method for these pathogens is hampered by the lack of a suitable animal model. This presentation is a review and summary of relevant research methodology and results. In order to develop a model for these coccidia, the effects of gamma radiation have been evaluated on unsporulated and sporulated oocysts of Toxoplasma gondii, a biologically similar coccidian. Unsporulated oocysts irradiated at @ 0.4 to 0.8 kGy sporulated but were not infective to mice. Sporulated oocysts irradiated at @ 0.4 kGy were able to excyst, and sporozoites were infective but not capable of inducing a viable infection in mice. T. gondii was detectable in mice fed irradiated (0.5 kGy) oocysts for up to 5 days but not at 7 days. Raspberries inoculated with sporulated T. gondii oocysts were rendered innocuous after irradiation at 0.4 kGy. These results indicated that irradiation at 0.5 kGy was an effective method to kill coccidian oocysts on fruits and vegetables.