Onchocerciasis‐associated epilepsy: From recent epidemiological and clinical findings to policy implications

Colebunders, Robert; Njamnshi, Alfred K.; Oijen, Marieke van; Mukendi, Déby; Kashama, Jean Marie; Mandro, Michel; Gumisiriza, Nolbert; Preux, Pierre‐Marie; Suykerbuyk, Patrick; Idro, Richard

doi:10.1002/epi4.12054

Cited by 61 publications

(70 citation statements)

References 43 publications

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“…In most PWE, no obvious other cause could be identified and their psycho-motoric development before the onset of seizures had been normal. The peak onset of epilepsy between the ages of seven and 16 years is a characteristic of OAE as observed elsewhere in Africa (Colebunders et al, 2016b(Colebunders et al, , 2017 when they became heavily infected with O. volvulus at a young age. An argument for this hypothesis is a recent study in South Sudan which showed that the age at onset of nodding seizures was around eight years, while the age of other forms of seizures was around 10 years (Colebunders et al, 2018).…”

Section: Discussionsupporting

confidence: 52%

Clinical presentation of epilepsy in six villages in an onchocerciasis endemic area in Mahenge, Tanzania

Bhwana

Mmbando

Dekker

et al. 2019

Epileptic Disorders

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Aims . To describe the clinical manifestations of epilepsy and access to antiseizure treatment in Mahenge in Central Tanzania, an onchocerciasis endemic area with a high prevalence of epilepsy. Methods . A door‐to‐door epilepsy prevalence survey was conducted in four rural and two sub‐urban villages. Trained community workers used five screening questions to identify persons suspected to have epilepsy. Such individuals were interviewed and examined by a neurologist or a medical doctor with additional training in epilepsy, and were tested for Onchocerca volvulus antibodies. Results . A total of 221 out of 8,062 (2.74%) surveyed individuals were confirmed to have epilepsy. The median age at seizure onset was 12 years (interquartile range: 7–16). Seventy‐nine persons with epilepsy (PWE) (36.1%) had a family member with epilepsy, which was a sibling in 52.1%. Tonic‐clonic seizures (142 individuals; 64.2%) were the most common seizure type. Nodding seizures were reported in 12.7% of PWE; the majority of them living in rural villages. Persons with nodding seizures reported more frequent seizures, presented with more psychiatric symptoms, and more often had onchocerciasis antibodies than those with other seizure types. The high rate of individuals with a seizure onset at between seven and 16 years is characteristic of onchocerciasis‐associated epilepsy (OAE). Of the PWE, 77.9% met the criteria for the clinical case definition of OAE. Eighty‐three PWE (37.6%) were not taking any antiepileptic medication. Phenobarbital was the antiepileptic drug most commonly prescribed in 76.1% of treated PWE. Conclusion . The high prevalence of epilepsy in rural villages in Mahenge most likely is related to the high prevalence of OAE. To prevent children developing OAE, strengthening the onchocerciasis elimination programme in Mahenge is urgently needed. Moreover, a decentralised epilepsy treatment programme is also needed to provide uninterrupted access to affordable antiepileptic drugs for the many PWE living in rural villages in the Mahenge area.

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Section: Discussionsupporting

confidence: 52%

Clinical presentation of epilepsy in six villages in an onchocerciasis endemic area in Mahenge, Tanzania

Bhwana

Mmbando

Dekker

et al. 2019

Epileptic Disorders

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“…In 414 of the 486 (85.2%) PWE for which data were available on all OAE criteria, OAE criteria were met. Seventy two PWE were not considered to have OAE for one or more of the following reasons: in 34 (47.2%) the seizures did not start between the ages of 3-18 years; and in 38 (52.7%) the medical history revealed a possible cause of epilepsy, including a perinatal event [1], measles [7], malaria [29] and head injury [3]. An additional 14 infants less than 3 years old also met the OAE criteria when the age of onset of epilepsy and duration of living in the village were not taken into account.…”

Section: Resultsmentioning

confidence: 99%

Clinical characteristics of onchocerciasis-associated epilepsy in villages in Maridi County, Republic of South Sudan

Colebunders

Abd-Elfarag

Carter

et al. 2018

Seizure

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To describe the clinical manifestations of persons with epilepsy (PWE) in onchocerciasis endemic villages in South Sudan. Methods: During a survey in Maridi County in May 2018, PWE were interviewed and examined in their households by a clinical officer or medical doctor. Onchocerciasis-associated epilepsy (OAE) was defined as ≥2 seizures without any obvious cause, starting between the ages of 3-18 years in previously healthy persons who had resided for at least 3 years in the onchocerciasis endemic area. Results: Seven hundred and thirty-six PWE were included in the study; 315 (42.8%) were females; median age was 18 years. A variety of seizure types were reported: generalized tonic-clonic seizures in 511 PWE (69.4%), absences in 15 (2.0%), focal motor seizures with full awareness in 7 (1.0%), focal motor seizures with impaired awareness in 25 (3.4%), brief episodes of hallucinations in 316 (43.9%) and nodding seizures in 335 (45.5%). The median age of onset of all seizures was 10 years, and 8 years for nodding seizures. PWE with nodding seizures presented with more cognitive disabilities. The diagnostic criteria for OAE were met by 414 (85.2%) of the 486 PWE with complete information. Eighty (11.0%) PWE presented with Nakalanga features. Only 378 (51.4%) PWE were taking anti-epileptic treatment. Conclusion: PWE presented with a wide spectrum of seizures. The high percentage of PWE who met the diagnostic criteria for OAE suggests that better onchocerciasis control could prevent new cases. Urgent action is needed to close the anti-epileptic treatment gap. different seizure presentations including nodding syndrome (NS) [2,3]. NS was first investigated in 2001-2 in Lui and Amadi in Western Equatoria region, South Sudan, by a team led by the World Health Organization (WHO) [4]. Three small case control studies (82 pairs in total) performed during these investigations showed that infections with Onchocerca volvulus diagnosed by skin snips were more often

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“…Nodding syndrome (NS) is a neurological disorder that manifests with a unique epilepsy type characterized by repeated head nodding, often in association with progressive neurocognitive impairment and physical decline [1][2][3]. It has been suggested that NS should be considered as one of the clinical presentations of onchocerciasisassociated epilepsy (OAE) [4,5]. However, the pathophysiology of how Onchocerca volvulus may cause epilepsy remains unknown.…”

Section: Introductionmentioning

confidence: 99%

Prevalence and incidence of nodding syndrome and other forms of epilepsy in onchocerciasis-endemic areas in northern Uganda after the implementation of onchocerciasis control measures

et al. 2020

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Background: Around 2007, a nodding syndrome (NS) epidemic appeared in onchocerciasis-endemic districts of northern Uganda, where ivermectin mass distribution had never been implemented. This study evaluated the effect of community-directed treatment with ivermectin (CDTI) and ground larviciding of rivers initiated after 2009 and 2012 respectively, on the epidemiology of NS and other forms of epilepsy (OFE) in some districts of northern Uganda. Methods: In 2012, a population-based community survey of NS/epilepsy was carried out by the Ugandan Ministry of Health in Kitgum and Pader districts. In August 2017, we conducted a new survey in selected villages of these districts and compared our findings with the 2012 data. In addition, two villages in Moyo district (where CDTI was ongoing since 1993) served as comparative onchocerciasis-endemic sites in which larviciding had never been implemented. The comparison between 2012 and 2017 prevalence and cumulative incidence were done using the Fisher's and Pearson's Chi-square tests at 95% level of significance. Results: A total of 2138 individuals in 390 households were interviewed. In the selected villages of Kitgum and Pader, there was no significant decrease in prevalence of NS and OFE between 2012 and 2017. However, the cumulative incidence of all forms of epilepsy decreased from 1165 to 130 per 100 000 persons per year (P = 0.002); that of NS decreased from 490 to 43 per 100 000 persons per year (P = 0.037); and for OFE from 675 to 87 per 100 000 persons per year (P = 0.024). The median age of affected persons (NS and OFE) shifted from 13.5 (IQR: 11.0-15.0) years in 2012 to 18.0 (IQR: 15.0-20.3) years in 2017; P < 0.001. The age-standardized prevalence of OFE in Moyo in 2017 was 4.6%, similar to 4.5% in Kitgum and Pader. Conclusions: Our findings support the growing evidence of a relationship between infection by Onchocerca volvulus and some types of childhood epilepsy, and suggest that a combination of biannual mass distribution of ivermectin and ground larviciding of rivers is an effective strategy to prevent NS and OFE in onchocerciasis-hyperendemic areas.

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Onchocerciasis‐associated epilepsy: From recent epidemiological and clinical findings to policy implications

Cited by 61 publications

References 43 publications

Clinical presentation of epilepsy in six villages in an onchocerciasis endemic area in Mahenge, Tanzania

Clinical presentation of epilepsy in six villages in an onchocerciasis endemic area in Mahenge, Tanzania

Clinical characteristics of onchocerciasis-associated epilepsy in villages in Maridi County, Republic of South Sudan

Prevalence and incidence of nodding syndrome and other forms of epilepsy in onchocerciasis-endemic areas in northern Uganda after the implementation of onchocerciasis control measures

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