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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Gamma Radiation on Viability of Encephalitozoon Spores, Encephalitozoon Hellem, and Encephalitosoon Intestinalis Spores

item Trout, James
item Palmer, Robert

Submitted to: Journal of Parasitology
Publication Type: Research Notes
Publication Acceptance Date: February 1, 2002
Publication Date: August 1, 2002
Citation: Li, X., Trout, J.M., Jenkins, M.C., Palmer, R.C., Fayer, R. 2002. Effects of gamma radiation on viability of encephalitozoon spores, encephalitozoon hellem, and encephalitosoon intestinalis spores. Journal of Parasitology. 88:812-813.

Interpretive Summary: Interpretive Summary: The microsporidian parasites Encephalitozoon cuniculi (Ec), Encephalitozoon intestinalis (Ei), and Encephalitozoon hellem (Eh) are human pathogens also found in wild and/or domesticated animals. Because surface water used for drinking, irrigation and recreation has been found contaminated with microsporidia and few methods to prevent human infection are known, the present study was undertaken to determine if gamma radiatio could reduce or eliminate infectivity with spores of these species. At doses of 1.5 and 2 kiloGrays spores of Ec and Ei were rendered noninfectious for cultured mammalian cells. At 3 kiloGrays development of Eh was greatly inhibited (97.6%).

Technical Abstract: Technical Abstract: Spores of Encephalitozoon cuniculi, Encephalitozoon hellem and Encephalitozoon intestinalis harvested from cultured mammalian cells were suspended in deionized water, exposed to gamma irradiation at doses from 0-3.0 kGy, and then tested for infectivity by inoculating spores into monolayer cultures of MDBK cells and examining the cultures for developing microsporidia 4 days later. As the dosage level of radiation increased, corresponding decreases were observed in the number of developing microsporidia for all 3 species. For E. cuniculi and E. intestinalis 100% inhibition of development was observed after exposure to 1.5 and 2.0 kGy, respectively. Although development of E. hellem was greatly inhibited (97.6% inhibition) after exposure to 3.0 kGy, complete inhibition was not obtained. These findings provide a guide for greatly reducing or eliminating infectious microsporidia from food by gamma irradiation.

Last Modified: 4/22/2015
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