Prevalence of neurocysticercosis in people with epilepsy in the Eastern Province of Zambia

Zambia is endemic for Taenia solium taeniosis and cysticercosis. In this single-centered, cross-sectional, community-based study, the role of neurocysticercosis (NCC) as a cause of epilepsy was examined. People with epilepsy (PWE, n = 56) were identified in an endemic area using a screening questionnaire followed by in-depth interviews and neurological examination. Computed tomography (CT) was performed on 49 people with active epilepsy (PWAE) and their sera (specific antibody and antigen detection, n = 56) and stools (copro-antigen detection, n = 54) were analyzed. The CT scan findings were compared to a group of 40 CT scan controls. Of the PWE, 39.3% and 23.2% were positive for cysticercal antibodies and antigens, respectively, and 14.8% for coproantigens (taeniosis). Lesions highly suggestive of NCC were detected in 24.5% and definite NCC lesions in 4.1% of CT scans of PWAE. This compares to 2.5% and 0%, respectively, in the control CT scans. Using the Del Brutto diagnostic criteria, 51.8% of the PWAE were diagnosed with probable or definitive NCC and this rose to 57.1% when the adapted criteria, as proposed by Gabriel et al. (adding the sero-antigen ELISA test as a major criterion), were used. There was no statistically significant relationship between NCC, current age, age at first seizure and gender. This study suggests that NCC is the single most important cause of epilepsy in the study area. Additional large-scale studies, combining a community based prevalence study for epilepsy with neuroimaging and serological analysis in different areas are needed to estimate the true impact of neurocysticercosis in endemic regions and efforts should be instituted to the control of T. solium

Diagnostic test results according to activity of epilepsy and CT scan results.

<p>*For Copro-Ag ELISA n = 49</p><p>** For Copro-Ag ELISA total n = 54</p><p>*** For Copro-Ag ELISA n = 5</p><p>**** For Copro-Ag ELISA total n = 48</p><p>PWAE… People with active epilepsy, PWIE… People with inactive epilepsy, NCC … Neurocysticercosis, CT… Computed tomography, EITB… Enzyme linked immunoelectrotransfer blot to detect cysticercus antibodies in serum, Ag-ELISA… Detection test for cysticercus antigens in serum, Copro-Ag ELISA… Detection test for antigens in stool to diagnose taeniosis</p><p>Diagnostic test results according to activity of epilepsy and CT scan results.</p

The age at examination and at first seizure, gender and clinical diagnosis of epilepsy is shown according to the Del Brutto and Gabriël et al. diagnostic criteria.

<p>NCC … Neurocysticercosis, F…Female, M… Male, SD… Standard deviation; <i>Generalized seizures within specific age range</i>: primary generalized seizures that start within a specific age range (mainly between 6 and 25 years when most of the idiopathic generalized epilepsies start); <i>Generalized seizures outside specific age range</i>: primary generalized seizures that lie outside the specific age range of most of the idiopathic generalized epilepsies, but have no focal start and no clinical signs of brain damage; <i>Generalized seizures with diffuse brain damage</i>: secondary generalized seizures with no clear focal start but clinically obvious diffuse brain damage; <i>Generalized seizures with focal signs</i>: secondary generalized seizures with a focal start or clear unilateral seizures but without major brain damage; <i>Complex partial seizures</i>: focal seizures with loss of consciousness (see also [<a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003972#pntd.0003972.ref020" target="_blank">20</a>])</p><p>The age at examination and at first seizure, gender and clinical diagnosis of epilepsy is shown according to the Del Brutto and Gabriël et al. diagnostic criteria.</p

Map of Zambia showing the study area in Katete district of the Eastern province.

<p>Map of Zambia showing the study area in Katete district of the Eastern province.</p

Draft of the study design.

<p>Draft of the study design.</p

Diagnosis of type of epilepsy after neurological examination.

<p>Diagnosis of type of epilepsy after neurological examination.</p

Reasons for exclusion and number of individuals excluded from the study.

<p>Reasons for exclusion and number of individuals excluded from the study.</p

Diagnosis of neurocysticercosis according to Del Brutto (2012) and Gabriël et al. (2012) diagnostic criteria.

<p>*n = 49</p><p>** n = 5, no CT scan results available</p><p>^# n = 40, only CT scan results available</p><p>PWAE… People with active epilepsy, PWIE… People with inactive epilepsy, NCC … Neurocysticercosis, CT… Computed tomography</p><p>Diagnosis of neurocysticercosis according to Del Brutto (2012) and Gabriël et al. (2012) diagnostic criteria.</p