| Title | Effect of intermittent oral administration of ponazuril on experimental Sarcocystis neurona infection of horses. | | Author(s) | Mackay RJ, Tanhauser ST, Gillis KD, Mayhew IG, Kennedy TJ | | Institution | Department of Large Animal Clinical Sciences, University of Florida, Gainesville, FL 32610. | | Source | Am J Vet Res 2008 Mar; 69(3):396-402. | | Abstract | Objective-To evaluate the effect of intermittent oral administration of ponazuril on immunoconversion against Sarcocystis neurona in horses inoculated intragastrically with S neurona sporocysts. Animals-20 healthy horses that were seronegative for S neurona-specific IgG. Procedures-5 control horses were neither inoculated with sporocysts nor treated. Other horses (5 horses/group) each received 612,500 S neurona sporocysts via nasogastric tube (day 0) and were not treated or were administered ponazuril (20 mg/kg, PO) every 7 days (beginning on day 5) or every 14 days (beginning on day 12) for 12 weeks. Blood and CSF samples were collected on day - 1 and then every 14 days after challenge for western blot assessment of immunoconversion. Clinical signs of equine protozoal myeloencephalitis (EPM) were monitored, and tissues were examined histologically after euthanasia. Results-Sera from all challenged horses yielded positive western blot results within 56 days. Immunoconversion in CSF was detected in only 2 of 5 horses that were treated weekly; all other challenged horses immunoconverted within 84 days. Weekly administration of ponazuril significantly reduced the antibody response against the S neurona 17-kd antigen in CSF. Neurologic signs consistent with EPM did not develop in any group; likewise, histologic examination of CNS tissue did not reveal protozoa or consistent degenerative or inflammatory changes. Conclusions and Clinical Relevance-Administration of ponazuril every 7 days, but not every 14 days, significantly decreased intrathecal anti-S neurona antibody responses in horses inoculated with S neurona sporocysts. Protocols involving intermittent administration of ponazuril may have application in prevention of EPM. | | Language | eng | | Pub Type(s) | Journal Article
| | PubMed ID | 18312139 |
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