Case definitions for onchocerciasis-associated epilepsy and nodding syndrome: A focused review

Cutsem, G Van; Fodjo, Joseph Nelson Siewe; Dekker, Marieke; Amaral, Luís-Jorge; Njamnshi, Alfred Kongnyu; Colebunders, Robert

doi:10.1016/j.seizure.2023.03.024

Cited by 23 publications

(16 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The latter has been illustrated by mathematical modelling [ 57 ], which suggests that children are at high risk of increasing microfilarial loads. Added to this, as previously described, ivermectin uptake in Mvolo was consistently lower among younger age groups, especially those aged five to ten years, who are most susceptible to developing OAE [ 8 ]. Understanding and addressing the underlying reasons for the low ivermectin uptake is therefore vital.…”

Section: Discussionsupporting

confidence: 62%

“…Similarly, in 2020, 264 out of 342 individuals (77%) with probable nodding syndrome experienced other types of seizures. This co-occurrence of nodding and other seizures is denoted as nodding syndrome plus and is within the spectrum of onchocerciasis-associated epilepsy [ 8 ]. § Data were only collected from 252 individuals with probable nodding syndrome in 2020 and 248 in 2022.…”

Section: Resultsmentioning

confidence: 99%

“…A probable case of NS was defined as a person with epilepsy characterised by repeated, involuntary episodes of head dropping during a brief period of reduced consciousness. Other potential features of NS included stunting, cognitive decline and spatial clustering of cases [ 8 ]. A person identified with probable NS experienced nodding seizures either at the time of the survey (ongoing nodding seizures) or had experienced them in the past.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Impact of annual community-directed treatment with ivermectin on the incidence of epilepsy in Mvolo, a two-year prospective study

Amaral,

Jada,

Ndjanfa

et al. 2024

PLoS Negl Trop Dis

View full text Add to dashboard Cite

Objectives The potential impact of cumulative community-directed treatment with ivermectin (CDTI) on epilepsy epidemiology in Mvolo County, South Sudan, an onchocerciasis-endemic area with high epilepsy prevalence, was investigated. Annual CDTI was introduced in 2002 in Mvolo, with interruptions in 2016 and 2020. Methods Comprehensive house-to-house surveys in Mvolo (June 2020 and 2022) identified cases of epilepsy, including probable nodding syndrome (pNS). Community workers screened households in selected sites for suspected epilepsy, and medical doctors confirmed the diagnosis and determined the year of seizure onset. The incidence of epilepsy, including pNS, was analysed using 95% confidence intervals (CIs). Data on ivermectin intake and onchocerciasis-associated manifestations (itching and blindness) were collected. Results The surveys covered 15,755 (2020) and 15,092 (2022) individuals, identifying 809 (5.2%, 95% CI: 4.8–5.5%) and 672 (4.5%, 95% CI: 4.1–4.8%) epilepsy cases, respectively. Each survey reported that a third of the surveyed population experienced skin itching, and 3% were blind. Epilepsy incidence per 100,000 person-years gradually declined, from 326.5 (95% CI: 266.8–399.1) in 2013–2015 to 96.6 (95% CI: 65.5–141.7) in 2019–2021. Similarly, pNS incidence per 100,000 person-years decreased from 151.7 (95% CI: 112.7–203.4) to 27.0 (95% CI: 12.5–55.5). Coverage of CDTI was suboptimal, reaching only 64.0% of participants in 2019 and falling to 24.1% in 2021 following an interruption in 2020 due to COVID-19 restrictions. Additionally, while 99.4% of cases had active epilepsy in 2022, less than a quarter of these had access to antiseizure medication. Conclusions The observed decrease in epilepsy incidence despite suboptimal CDTI coverage highlights the potential impact of onchocerciasis control efforts and underscores the need to strengthen these efforts in Mvolo County and across South Sudan. As a proactive measure, Mvolo and neighbouring counties are transitioning to biannual CDTI. Furthermore, the substantial epilepsy treatment gap in Mvolo should be addressed.

show abstract

Section: Discussionsupporting

confidence: 62%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Impact of annual community-directed treatment with ivermectin on the incidence of epilepsy in Mvolo, a two-year prospective study

Amaral,

Jada,

Ndjanfa

et al. 2024

PLoS Negl Trop Dis

View full text Add to dashboard Cite

show abstract

“…OAE presents with a wide spectrum of epileptic seizures, including generalized tonic-clonic seizures, myoclonic seizures, absence seizures and head nodding seizures (Colebunders et al 2018a). Nodding and Nakalanga syndrome are considered to be phenotypic presentations of OAE (Colebunders et al 2018a;Van Cutsem et al 2023). Nakalanga syndrome is characterized by severe growth retardation, delayed sexual development, mental impairment, facial deformation, kyphoscoliosis, and epileptic seizures (Föger et al 2017;Siewe Fodjo et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Cameroonian blackflies (Diptera: Simuliidae) harbour a plethora of (RNA) viruses

De Coninck,

Hadermann,

Ingletto

et al. 2024

Preprint

Self Cite

View full text Add to dashboard Cite

Strong epidemiological evidence suggests that onchocerciasis may be associated with epilepsy – hence the name onchocerciasis-associated epilepsy (OAE). However, the pathogenesis of OAE still needs to be elucidated, as recent studies failed to detect Onchocerca volvulus in the central nervous system of persons with OAE. Therefore, it was suggested that a potentially neurotropic virus transmitted by blackflies could play a role in triggering OAE. To investigate this hypothesis, adult blackflies were collected in an onchocerciasis-endemic area with a high OAE prevalence in the Ntui Health District, Cameroon. A whole-genome shotgun sequencing approach was used to detect viral sequences in fifty-five pools of ten blackflies. A very high abundance of viral reads was detected across multiple (novel) viral families, including viral families associated with human disease. Although, no genomes closely related to known neurotropic viruses were found in the blackfly virome, the plethora of novel viruses representing novel species, genera and even families, warrant further exploration for their potential to infect vertebrates. These results could serve as a first step for studying the viruses associated with the hematophagous blackfly, which also could be present in their nematode host O. volvulus. Exploring the diversity of viruses in blackflies should be included in the active surveillance of zoonotic diseases.

show abstract

“…What is crucially important at the moment is a simple diagnostic approach or tool to differentiate OAE from other forms of epilepsy. Currently this is achieved by using the proposed OAE definition [ 14 ] which requires (1) good clinical history taking, (2) using epidemiological arguments, and (3) point-of-care onchocerciasis tests like the OV16 rapid diagnostic tests (or skin snip testing when possible). One major problem in overlapping Taenia solium - and onchocerciasis-endemic regions is to differentiate OAE from epilepsy caused by neurocysticercosis (NCC).…”

mentioning

confidence: 99%

Onchocerciasis-associated epilepsy and biomarkers

Colebunders,

Hadermann,

Njamnshi

et al. 2024

PLoS Negl Trop Dis

Self Cite

View full text Add to dashboard Cite

Case definitions for onchocerciasis-associated epilepsy and nodding syndrome: A focused review

Cited by 23 publications

References 43 publications

Impact of annual community-directed treatment with ivermectin on the incidence of epilepsy in Mvolo, a two-year prospective study

Impact of annual community-directed treatment with ivermectin on the incidence of epilepsy in Mvolo, a two-year prospective study

Cameroonian blackflies (Diptera: Simuliidae) harbour a plethora of (RNA) viruses

Onchocerciasis-associated epilepsy and biomarkers

Contact Info

Product

Resources

About