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. 2018 Aug 1;7(1):68.
doi: 10.1186/s40249-018-0452-1.

High prevalence of epilepsy in onchocerciasis endemic health areas in Democratic Republic of the Congo

Evy Lenaerts  1   2 , Michel Mandro  3   4 , Deby Mukendi  5 , Patrick Suykerbuyk  3 , Housseini Dolo  3   6 , Deogratias Wonya'Rossi  7   8 , Françoise Ngave  8 , Chellafe Ensoy-Musoro  9 , Anne Laudisoit  3   10 , An Hotterbeekx  3 , Robert Colebunders  11   12
Affiliations

High prevalence of epilepsy in onchocerciasis endemic health areas in Democratic Republic of the Congo

Evy Lenaerts et al. Infect Dis Poverty. .

Abstract

Background: A high prevalence of epilepsy has been observed in many onchocerciasis endemic regions. This study is to estimate the prevalence of active epilepsy and exposure to Onchocerca volvulus infection in a rural population in Ituri province, Democratic Republic of Congo.

Methods: In August 2016, a community-based cross-sectional study was conducted in an onchocerciasis endemic area in the rural health zone of Logo, Ituri Province. Households within two neighbouring health areas were randomly sampled. To identify persons with epilepsy, a three-stage approach was used. In the first stage, all individuals of the selected households were screened for epilepsy by non-medical field workers using a validated 5-item questionnaire. In the second and third stage, suspected cases of epilepsy were examined by non-specialist medical doctors, and by a neurologist, respectively. A case of epilepsy was defined according to the 2014 International League Against Epilepsy (ILAE) guidelines. Exposure to O. volvulus was assessed by testing for IgG4 antibodies to an O. volvulus antigen (OV16 Rapid Test,) in individuals aged 3 years and older.

Results: Out of 1389 participants included in the survey, 64 were considered to have active epilepsy (prevalence 4.6%) (95% confidence interval [CI]: 3.6-5.8). The highest age-specific epilepsy prevalence estimate was observed in those aged 20 to 29 years (8.2%). Median age of epilepsy onset was 10 years, with a peak incidence of epilepsy in the 10 to 15 year-old age group. OV16 test results were available for 912 participants, of whom 30.5% (95% CI, 27.6-33.6) tested positive. The prevalence of OV16 positivity in a village ranged from 8.6 to 68.0%. After adjusting for age, gender and ivermectin use, a significant association between exposure to onchocerciasis and epilepsy was observed (adjusted odds ratio = 3.19, 95% CI: 1.63-5.64) (P < 0.001).

Conclusions: A high prevalence of epilepsy and a significant association between epilepsy and exposure to O. volvulus were observed in the population in Ituri province, Democratic Republic of Congo. There is an urgent need to implement a CDTI programme and to scale up an epilepsy treatment and care programme.

Keywords: Democratic Republic of Congo; Onchocerciasis; epilepsy; Prevalence.

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Conflict of interest statement

Ethics approval and consent to participate

The study was approved by the Ethical Review Board of the University of Antwerp, Belgium and the Ethical Review Committee of Ngaliema Hospital, Kinshasa, DRC. Informed consent was obtained from the head of the village, the head of the household and from all adults belonging to the household. In case of children/minors/invalid adults, informed consent was obtained from the parents/caregivers. Those aged 12 years and older were asked to sign a supplementary section on the form stating their voluntary approval of participation. Participants were free to abstain from participation in the study or to withdraw consent to participate at any time. No direct benefits for participation in the study were provided.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Map of the study area. Location of Ituri Province in the north-east of the Democratic Republic of Congo (left), and location of Logo health zone within Ituri Province, west of Lake Albert (right)
Fig. 2
Fig. 2
Distribution of sampled households by village. Topographical map showing the distribution of sampled households by village, with the size of the circles being proportional to the size of the households
Fig. 3
Fig. 3
Three-stage process to identify persons with active epilepsy. In the first stage, all individuals of the selected households were screened for epilepsy by non-medical field workers. In the second and third stage, suspected cases of epilepsy were examined by non-specialist medical doctors, and by a neurologist, respectively. Those suspected cases of epilepsy who were not seen by the neurologist, were considered to be ‘true’ cases of epilepsy if they had at least three positive answers on the epilepsy screening questionnaire or had previously been told by a doctor to have epilepsy (review and consensus)
Fig. 4
Fig. 4
Distribution of people with epilepsy and people without epilepsy. Topographical map showing the distribution of people with epilepsy (red signs) and those without epilepsy (grey dots). Red-coloured village names refer to Kanga health area, whereas the green-coloured village names refer to Draju health area
Fig. 5
Fig. 5
Epilepsy prevalence by village. Pie charts demonstrating epilepsy prevalence by village with dark-coloured slices being proportional to the number of people with epilepsy, and light-coloured slices being proportional to the number of people without epilepsy. See Additional file 2 for absolute numbers of people with epilepsy by village and corresponding village-specific epilepsy prevalence.
Fig. 6
Fig. 6
Age at onset of epilepsy. Bar chart showing the age at onset of epilepsy
Fig. 7
Fig. 7
OV16 seroprevalence by village. Pie charts demonstrating OV16 seroprevalence by village with dark-coloured slices being proportional to the number of people with positive OV16 test results, and light-coloured slices being proportional to the number of people with negative OV16 test results. See Additional file 3 for absolute numbers of people with positive and negative OV16 test results and corresponding percentages of individuals with a positive OV16 antibody test result by village
See this image and copyright information in PMC

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