TIME-RESPONSE CURVE OF OXFENDAZOLE IN THE TREATMENT OF SWINE CYSTICERCOSIS

Human Taenia solium cysticercosis is a major cause of epilepsy in deve loping countries, and porcine infection causes widespread economic los ses because of infested pork. Recently, the use of oxfendazole (OFZ) f or porcine cysticercosis provided, for the first time, an effective, s ingle-dose treatment. We performed a controlled study to determine the time required between treatment with a single dose of OFZ and the dea th of cysticerci to define its applicability as preslaughter treatment or as a field control measure. Twenty naturally infected pigs were in cluded in this study. Sixteen received a single dose (30 mg/kg) of OFZ , and were killed in groups of four at one, two, four, and 12 weeks af ter treatment. Four untreated controls were killed at week 12, No adve rse reactions to OFZ were noted. A clear decrease in viability and num ber of cysts was evident after the first week after therapy, but even at week 4 some viable cysticerci were found in all samples. Twelve wee ks after treatment, all meat appeared clear and only minuscule scars r emained, except in one animal that had viable brain cysts. This study confirms the efficacy of a single dose of 30 mg/kg of OFZ for porcine cysticercosis but demonstrates that preslaughter treatment of pigs wit h OFZ will not be useful in controlling cysticercosis. The inclusion o f porcine treatment with OFZ in mass cysticercosis control programs is , however, highly promising because it is a simple, ineffective, inexp ensive, and potentially sustainable able method for decreasing the por cine reservoir of cysticercosis in disease-endemic countries.