Submitted to: American Society of Parasitologists
Publication Type: Abstract Only
Publication Acceptance Date: April 28, 2009
Publication Date: August 14, 2009
Citation: Jenkins, M.C., Obrien, C.N., Rosenthal, B.M., Fayer, R. 2009. Gamma irradiation of Cryptosporidium parvum oocysts affects intracelluar levels of the viral symbiont CPV. American Society of Parasitologists. 84th American Society of Parasitologists Meeting. p. 54 Technical Abstract: Previous studies have shown a dose-dependent effect of gamma irradiation on Cryptosporidium parvum development in neonatal mice and newborn calves. In mice, C. parvum oocysts exposed to 200 Gy showed nearly complete inability to develop as measured by C. parvum-specific quantitative PCR of ileal tissue. In calves, higher irradiation doses (400 Gy) were required to prevent parasite development as measured by oocyst shedding. The present study was conducted to determine the extent of development of C. parvum and its viral symbiont (CPV) after exposure to irradiation, using a cell culture model. Cryptosporidium parvum oocysts were exposed to 0-, 200-, or 400 Gy gamma irradiation, excysted in vitro, and inoculated into HCT-8 cell culture. RNA was harvested from cells and culture medium at 2, 24, and 48 hr post-inoculation, and analyzed by standard and real-time RT-PCR to estimate parasite and CPV abundance at various times post-inoculation. Preliminary results indicate that CPV- and C. parvum-specific RNA were present in both cells and culture medium, suggesting that both virus and parasite were released from host cells during development. Also, irradiation doses of 400Gy resulted in lower CPV levels compared to 200 Gy and non-irradiated oocysts at 24 and 48 hr post-infection. Studies are underway to evaluate the effects of higher doses of gamma irradiation on the parasite and its symbiont.