| This thesis describes the effects of pyrantel tartrate (Strongid RTM-C) on Sarcocystis neurona merozoites and sporozoites both in vitro and in a gamma interferon knock-out mouse model of the disease equine protozoal myeloencephalitis (EPM). Anecdotal reports from private practicing veterinarinans suggest that horses fed daily StrongidRTM-C showed a lower incidence of clinical EPM than those not fed the dewormer, leading us to formulate the hypothesis that pyrantel tartrate affects the viability of S. neurona.; The results of this study show pyrantel tartrate, at concentrations greater than 2.5 mM, is 100% lethal to S. neurona merozoites. Pyrantel tartrate at concentrations greater than 5 mM is lethal to S. neurona sporozoites. Pyrantel tartrate given orally to gamma interferon knock-out mice at the dose of 2.5 mM increased the mean survival time of mice. Acetylcholine (ACh) chloride, at concentrations similar to that of pyrantel tartrate, did not produce the same lethal consequences in S. neurona merozoites, indicating that the drug is unlikely to work at cholinergic receptors in this parasite.; From these studies, we concluded that pyrantel tartrate has the potential to be effective against the merozoite and sporozoite stages of S. neurona, if high enough concentrations of the drug can be delivered effectively in vivo. Efficacy against the parasite in vitro was demonstrated to be dose dependent and repeatable in cell culture. |
