The effects of heat and cobalt-60 gamma-radiation on excystation of the rat coccidium, Eimeria nieschulzi Dieben, 1924.

Sporulated oocysts of Eimeria nieschulzi Dieben, a rat coccidium, were exposed for 1 hr to Cobalt-60 gamma-radiation (15, 30, or 60k-rads), to heat (35, 40, or 45 C) , or to both concurrently (15, 30, OR 60 K-RADS AT 35 C) to compared the excystation capabilities of treated vs nontreated parasites. Intact treated oocysts appeared structurally unaltered when viewed with the light microscope. Excystation of sporozoites occured in all treated groups when their sporocysts were exposed to a trypsin-sodium taurocholate (TST) fluid, but after 150 min in TST the excystation rate was significantly lower than in nontreated sporocysts. Sporozoites which excysted from treated sporocysts were abnormal both in the excystation process and in their form and movement once outside the sporocysts.