Taenia solium cysticercosis is an important cause of human disease in many developing countries. Porcine
cysticercosis is a vital link in the transmission of this disease and impairs meat production. A treatment for porcine
cysticercosis may be an effective way of preventing human disease that would also benefit pig farmers, facilitating control programs in disease-endemic regions. Previous research suggests that
reinfection with
cysticercosis or
immunotherapy with cysticercal
antigens may cause degeneration of cysticerci, potentially curing porcine
cysticercosis. Therefore, a blinded, randomized, controlled study to assess the efficacy and safety of
immunotherapy in 28 naturally parasitized pigs was performed. Four groups of pigs with similar weights were inoculated 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 variable, with both severe and minimal inflammatory reactions seen in adjacent cysticerci in all pigs. Nine (64%) of 14 pigs given
immunotherapy developed new antibody bands on electroimmunotransfer blot compared with one (7%) of 14 control pigs (P < 0.01). Treatment with AA in adjuvant caused a significant increase in the proportion of cysticerci that failed to evaginate and were, therefore, not viable for infecting humans (34% for pigs given AA in adjuvant compared with 10% for adjuvant alone; P < 0.04). Although
immunotherapy caused a statistically significant decrease in the viability of cysticerci, this immunologic reaction was not great enough to prevent human disease.