Evaluation of Eimeria krijgsmanni as a murine model for testing the efficacy of anti-parasitic agents.

Murine Eimeria spp. have been used as effective models of disease instead of large mammalian hosts such as cattle. We attempted to establish in vivo and in vitro assays using a murine intestinal protozoan, Eimeria krijgsmanni, which we previously isolated, to test anti-parasitic agents. Consequently, when mice were treated with sulfur drugs or toltrazuril, which are commercially available for livestock. Furthermore, sporulated oocysts and excysted sporozoites of E. krijgsmanni were treated with naturally occurring substances (lactoferrin, longicin, and curcumin). Although exposure to these substances did not affect oocyst infectivity, sporozoite viability decreased by 60% with longicin. However, direct injection of sporozoites treated with longicin into mice ceca did not result in any changes in the oocyst shedding pattern compared with control mice. The results suggest that E. krijgsmanni could be resistant to these anti-parasitic agents and might therefore have different characteristics to other apicomplexan parasites.