Neurocysticercosis: association between seizures, serology, and brain CT in rural Peru

Neurocysticercosis (NCC) is the commonest helminthic CNS infection and the main cause of adult-onset seizures in developing countries, also frequent in industrialized countries because of immigration from endemic zones. Although NCC is commonly seen in individuals with seizures in endemic areas, its role as a cause of epilepsy has been questioned on the basis of the poor methodology of published studies.

To determine, in a cysticercosis-endemic area of the northern Peruvian coast, the frequency of 1) epileptic seizures, 2) serum antibodies to Taenia solium, 3) NCC-compatible findings on brain CT, and 4) the associations between these variables.

A community-wide screening survey for possible seizure cases was performed using a validated questionnaire. Positive respondents were later examined in the field by neurologists. Seizure cases were categorized as single seizure, active epilepsy, or inactive epilepsy. Serology was performed for all consenting individuals using immunoblot. Noncontrast brain CT scans were performed in all individuals with seizures and two groups of control subjects without seizures (seropositive and seronegative).

The screening survey was applied to 903 permanent residents. Most positive respondents (114/137 [83.2%]) were examined by neurologists. The overall prevalence of epilepsy was 32.1 per 1,000 and that of active epilepsy was 16.6 per 1,000. Seroprevalence was 24.2% (200/825). Seroprevalence was associated with seizures (odds ratio 2.14; p = 0.026). Brain CT abnormalities compatible with NCC were more frequent in individuals with seizures and in those seropositive.

In this hyperendemic area, an important proportion of seizure cases are associated with neurocysticercosis as demonstrated by serology or brain CT.