IMMUNOTHERAPY FOR PORCINE CYSTICERCOSIS - IMPLICATIONS FOR PREVENTIONOF HUMAN-DISEASE

Taenia solium cysticercosis is an important cause of human disease in many developing countries. Porcine cysticercosis is a vital link in th e transmission of this disease and impairs meat production. A treatmen t for porcine cysticercosis may be an effective way of preventing huma n disease that would also benefit pig farmers, facilitating control pr ograms in disease-endemic regions. Previous research suggests that rei nfection with cysticercosis or immunotherapy with cysticercal antigens may cause degeneration of cysticerci, potentially curing porcine cyst icercosis. Therefore, a blinded, randomized, controlled study to asses s the efficacy and safety of immunotherapy in 28 naturally parasitized pigs was performed. Four groups of pigs with similar weights were ino culated twice with membrane-enriched cysticercal antigens (MA), saline , aqueous-soluble crude cysticercal antigens (AA) in adjuvant (Freund' s complete then incomplete), or adjuvant alone. Immunotherapy was well tolerated but had no consistent effect on the macroscopic appearance of cysticerci or eosinophil count. Histopathologic findings were varia ble, with both severe and minimal inflammatory reactions seen in adjac ent cysticerci in all pigs. Nine (64%) of 14 pigs given immunotherapy developed new antibody bands on electroimmunotransfer blot compared wi th one (7%) of 14 control pigs (P < 0.01). Treatment with AA in adjuva nt caused a significant increase in the proportion of cysticerci that failed to evaginate and were, therefore, not viable for infecting huma ns (34% for pigs given AA in adjuvant compared with 10% for adjuvant a lone; P < 0.04). Although immunotherapy caused a statistically signifi cant decrease in the viability of cysticerci, this immunologic reactio n was not great enough to prevent human disease.