DIAGNOSIS OF TAENIA-SAGINATA CYSTICERCOSIS IN KENYAN CATTLE BY ANTIBODY AND ANTIGEN ELISA

Sera from calves, either experimentally or naturally infected with Tae nia saginata, were screened for an antibody response to T. saginata, a nd for parasite antigen, by enzyme-linked immunosorbent assays (ELISAs ). An antibody response was detected by 3 weeks post infection (p.i.), rose to a peak at 10-12 weeks p.i., and was still in evidence 1 year p.i. Parasite antigen was first detected 4-7 weeks p.i. and persisted until the end of the experiment, over 1 year p.i. In the experimentall y infected animals, cattle with 14 or more live cysticerci had detecta ble levels of parasite antigen in their sera at slaughter, while anima ls with live cyst burdens ranging from 0 to 4 were negative. Furthermo re, levels of circulating antigen were positively correlated with live cysticercus burden in the experimental animals. In naturally infected cattle, 83% (5/6) of those with 30 or more live cysts, and 22% (5/23) of those with 1-29 live cysts, could be detected by the ELISA for par asite antigen, although no significant correlation between antigen lev el and live cyst burden could be detected. Antibody levels were not fo und to be associated with cyst burdens in either experimentally or nat urally infected cattle. In slaughterhouse cattle, the antigen assay wa s almost three times as sensitive as meat inspection. However, there w as no agreement between cattle found positive at meat inspection and t hose found positive by the antigen detection ELISA. One possible reaso n is that the ELISA only detects live cysts, while lesions left by dea d cysts are more noticeable at meat inspection. The mouse monoclonal a ntibody-based antigen detection ELISA is of value for the diagnosis of naturally occurring, viable, T. saginata cysticercosis in live cattle and has an immediate application for field based epidemiological stud ies designed to determine prevalence.