A population-based, case-control study of Taenia solium taeniasis and cysticercosis

A two-phase study was conducted in a rural community in Honduras, to evalua te the association between neurocysticercosis (NCC) diagnosed by computed t omography (CT), epilepsy, seropositivity for antibodies to the cysticerci o f Taenia solium [determined by enzyme-linked-immunoelectrotransfer-blot (EI TB) assays], intestinal infection with this parasite, and various epidemiol ogical factors. Of the 480 individuals studied in the first phase, 17% were seropositive and 2.5% supplied faecal samples which contained T. solium eg gs. In the second phase, 148 individuals (74 of the seropositive subjects f rom the first phase and 74 matched controls from the seronegatives) underwe nt CT and neurological examinations. The CT results appeared normal in 110 (74%) of the 148, showed anatomical abnormality in seven (5%), and active o r calcified lesions compatible with NCC in 31 (23% of the seropositives and 19% of the seronegatives). Only five of the latter had neurological sympto ms (two being epileptics) and only five lived in households in which intest inal taeniasis had been detected. Subject age was significantly associated with NCC-compatible lesions but all the other factors investigated, includi ng seropositivity, showed no significant association with the CT findings. The overall sensitivity of the EITB assays was found to be 55%, Taken toget her, the present results indicate that, even though it is a valuable tool i n determining transmission levels in sero-epidemiological studies, the EITB assay should not be used to predict the existance of NCC or to estimate th e prevalence of NCC. The results do provide further evidence that taeniasis and cysticercosis are widely prevalent in Honduras, and indicate that much larger studies of hyper-endemic communities may be necessary if the factor s associated with the transmission of T. solium are to be elucidated.