Sera from 9,254 individuals that presented at one of three
outpatient clinics in Quito, Ecuador were assayed by indirect
hemagglutination for the presence of antibodies reactive with
antigens from Taenia solium cysts. Immunoblot analysis of 81
selected sera with IHA titers ranging from 0 to 1,028 showed
that a titer of =/} 32 was suggestive of exposure to the
parasite. Nine percent (9%) of the 9,254 patients had titers
of 32 or greater. Of 3,503 sera from one clinic, which
included sera from food handlers undergoing yearly physicals,
390 (11%) were positive. In addition, a correlation with age
was seen in some, but not all, populations. In situations
where age-related effects were noted, the highest incidence
was seen in the youngest (0-20 years) and in the oldest (51-60
years) group. Thus, a resurgence of infection after a period
of lower prevalence may be developing. Overall, this study
shows that cysticercosis is relatively common and potentially
a serious health problem in this region.