High Prevalence of Cysticercosis in People with Epilepsy in Southern Rwanda

<div><p>Background</p><p>Neurocysticercosis (NCC), the central nervous system infection by <i>Taenia solium</i> larvae, is a preventable and treatable cause of epilepsy. In Sub-Saharan Africa, the role of NCC in epilepsy differs geographically and, overall, is poorly defined. We aimed at contributing specific, first data for Rwanda, assessing factors associated with NCC, and evaluating a real-time PCR assay to diagnose NCC in cerebrospinal fluid (CSF).</p><p>Methodology/Principal findings</p><p>At three healthcare facilities in southern Rwanda, 215 people with epilepsy (PWE) and 51 controls were clinically examined, interviewed, and tested by immunoblot for cysticerci-specific serum antibodies. Additionally, CSF samples from PWE were tested for anticysticercal antibodies by ELISA and for parasite DNA by PCR. Cranial computer tomography (CT) scans were available for 12.1% of PWE with additional symptoms suggestive of NCC. The Del Brutto criteria were applied for NCC diagnosis. Cysticerci-specific serum antibodies were found in 21.8% of PWE and 4% of controls (odds ratio (OR), 6.69; 95% confidence interval (95%CI), 1.6–58.7). Seropositivity was associated with age and lack of safe drinking water. Fifty (23.3%) PWE were considered NCC cases (definitive, based on CT scans, 7.4%; probable, mainly based on positive immunoblots, 15.8%). In CSF samples from NCC cases, anticysticercal antibodies were detected in 10% (definitive cases, 25%) and parasite DNA in 16% (definitive cases, 44%). Immunoblot-positive PWE were older (medians, 30 <i>vs.</i> 22 years), more frequently had late-onset epilepsy (at age >25 years; 43.5% <i>vs.</i> 8.5%; OR, 8.30; 95%CI, 3.5–20.0), and suffered from significantly fewer episodes of seizures in the preceding six months than immunoblot-negative PWE.</p><p>Conclusions/Significance</p><p>NCC is present and contributes to epilepsy in southern Rwanda. Systematic investigations into porcine and human cysticercosis as well as health education and hygiene measures for <i>T. solium</i> control are needed. PCR might provide an additional, highly specific tool in NCC diagnosis.</p></div

Diagnostic data for all PWE with NCC according to the Del Brutto criteria.

‡<p>cystic lesion without scolex, single or multiple ring or nodular enhancing lesion, or parenchymal round calcification <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002558#pntd.0002558-DelBrutto2" target="_blank">[14]</a>, details given in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002558#pntd.0002558.s002" target="_blank">Table S1</a>.</p>(+)*<p>, positive only with the maximum CSF volume (1.2–1.8 ml).</p>#<p>only 0.2 ml CSF for one PCR available.</p><p>n.a., no serum sample available.</p

Odds ratios and adjusted odds ratios (95% confidence intervals) for a positive immunoblot result in PWE.

a<p>, data are medians (range) for age and proportions (%, n/n) among PWE with and without a positive immunoblot;</p>b<p>, adjusted odds ratios originate from a logistic regression model including all shown variables, n = 211, correlation coefficient R² = 0.17.</p

Diagnostic data for PWE for whom no CT scans were available and who were classified “probable NCC cases” due to positive immunoblot results, clinical manifestation, and epidemiology (n = 31).

(+)*<p>, positive only with the maximum CSF volume (1.2–1.8 ml).</p>#<p>only 0.2 ml CSF for one PCR available.</p

Selected characteristics of PWE with NCC (defined by a positive serum immunoblot result).

*<p>cystic lesion without scolex, single or multiple ring or nodular enhancing lesion, or parenchymal round calcification <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002558#pntd.0002558-DelBrutto2" target="_blank">[14]</a>, details given in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002558#pntd.0002558.s002" target="_blank">Table S1</a>.</p>#<p>hydrocephalus or abnormal enhancement of the leptomeninges <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0002558#pntd.0002558-DelBrutto2" target="_blank">[14]</a>.</p

Odds ratios and adjusted odds ratios (95% confidence intervals) for epilepsy.

a<p>, data are medians (range) for age and proportions (%, n/n) among PWE and controls, respectively;</p>b<p>, adjusted odds ratios originate from a logistic regression model including all shown variables, n = 260, correlation coefficient R² = 0.44;</p>c<p>, data for one person with epilepsy missing;</p>d<p>, born elsewhere;</p>e<p>, data for four PWE and one control missing;</p>f<p>, removing the variable “Residence, district” from the model would lead to an aOR of 30.96 (95%CI, 4.52–212.22) for the cycticercosis immunoblot; removing the variable “Residence at current location since”, the aOR would change to 32.39 (95%CI, 4.48–234.15); removing both, the aOR would turn 36.05 (95%CI, 5.16–252.06).</p