title: Nodding syndrome and epilepsy in onchocerciasis endemic regions: comparing preliminary observations from South Sudan and the Democratic Republic of the Congo with data from Uganda.
abstract: BACKGROUND
  Nodding syndrome (NS) is an epilepsy disorder occurring in children in South Sudan, northern Uganda and Tanzania. The etiology of NS is unknown, but epidemiological studies demonstrate an association between NS and onchocerciasis.
  
  
  METHODS
  Between November 2013 and July 2015 we visited onchocerciasis endemic regions in South Sudan, Uganda, and the Democratic Republic of the Congo (DRC) to assess the epilepsy situation. In South Sudan we interviewed patients and affected families, health officials, colleagues and healthcare workers, and performed a small household survey to estimate the epilepsy prevalence in the village of Mvolo, Western Equatoria State. Most information from Uganda was collected through discussions with colleagues and a review of published literature and reports. In the Bas-Uélé district of the DRC, we visited the villages of Liguga, Titule and Dingila, interviewed patients with epilepsy and family members and conducted a preliminary entomological assessment.
  
  
  RESULTS
  In South Sudan there is an ongoing NS and epilepsy epidemic in the Western Equatoria state that started around 1990. A survey of 22 households in Mvolo revealed that 28 out of 168 (16.7%) children suffered from NS or another form of epilepsy. Thirteen (59%) households had at least one child, and nine (41%) households at least two children with NS or another form of epilepsy. In northern Uganda, an NS and epilepsy epidemic started around 2000. The occurrence of new NS cases has been in decline since 2008 and no new NS cases were officially reported in 2013. The decline in NS cases coincided with the bi-annual distribution of ivermectin and the treatment of blackfly-breeding rivers with larvicides. In Bas-Uélé district in the DRC, epilepsy appears to be endemic with cases clustered in villages close to blackfly-infested, rapid-flowing rivers. The majority of epilepsy cases in Liguga, Dingila and Titule presented with generalized (tonic-clonic) seizures without nodding, but with mental retardation. In Titule, an epilepsy prevalence of 2.3% was documented. The only anthropophilic species of blackfly collected in the region belonged to the Simulium damnosum complex.
  
  
  CONCLUSIONS
  Blackflies may play a key role in the transmission of an etiological agent that either directly or indirectly cause, not only NS, but also other forms of epilepsy in onchocerciasis endemic regions.
authors.affiliation: Global Health Institute, Gouverneur Kinsbergen Centrum, University of Antwerp, Doornstraat 331, 2610, Antwerp, Belgium. robert.colebunders@uantwerpen.be.|Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium. robert.colebunders@uantwerpen.be.
authors.forename: Robert
authors.initials: R
authors.lastname: Colebunders
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Adam
authors.initials: A
authors.lastname: Hendy
authors.affiliation: Biology Department, San Diego State University, San Diego, USA.
authors.forename: John L
authors.initials: JL
authors.lastname: Mokili
authors.affiliation: Ministry of Health, Kampala, Uganda.
authors.forename: Joseph Francis
authors.initials: JF
authors.lastname: Wamala
authors.affiliation: Faculty of Medicine, Gulu University, Gulu, Uganda.
authors.forename: Joice
authors.initials: J
authors.lastname: Kaducu
authors.affiliation: Department of Neglected Tropical Diseases, Ministry of Health, Juba, Republic of South Sudan.
authors.forename: Lucia
authors.initials: L
authors.lastname: Kur
authors.affiliation: National Onchocercosis Control Program, Ministry of Health, Kisangani, Democratic Republic of the Congo.
authors.forename: Floribert
authors.initials: F
authors.lastname: Tepage
authors.affiliation: Provincial Health Division Ituri, Ministry of Health, Bunia, Democratic Republic of the Congo.
authors.forename: Michel
authors.initials: M
authors.lastname: Mandro
authors.affiliation: Medical Doctor Bunia, Bunia, Province Orientale, Democratic Republic of the Congo.
authors.forename: Gisele
authors.initials: G
authors.lastname: Mucinya
authors.affiliation: Provincial Ministry of Public Health, Kisangani, Province Orientale, Democratic Republic of the Congo.
authors.forename: Germain
authors.initials: G
authors.lastname: Mambandu
authors.affiliation: Biodiversity Surveillance Center, Kisangani University, Kisangani, Democratic Republic of the Congo.
authors.forename: Michel Yendema
authors.initials: MY
authors.lastname: Komba
authors.affiliation: General Reference Hospital of Dingila, Dingila, Democratic Republic of the Congo.
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Lumaliza
authors.affiliation: Global Health Institute, Gouverneur Kinsbergen Centrum, University of Antwerp, Doornstraat 331, 2610, Antwerp, Belgium.|Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Marieke
authors.initials: M
authors.lastname: van Oijen
authors.affiliation: Global Health Institute, Gouverneur Kinsbergen Centrum, University of Antwerp, Doornstraat 331, 2610, Antwerp, Belgium.|Institute of Integrative Ecology, School of Biological Sciences, University of Liverpool, Liverpool, UK.
authors.forename: Anne
authors.initials: A
authors.lastname: Laudisoit
mesh_terms: D015023:Democratic Republic of the Congo / Q000453:epidemiology; D019353:Endemic Diseases / Q000706:statistics & numerical data*; D004827:Epilepsy / Q000150:complications* / Q000453:epidemiology*; D006801:Humans; D064128:Nodding Syndrome / Q000150:complications* / Q000453:epidemiology*; D009855:Onchocerciasis / Q000150:complications* / Q000453:epidemiology*; D000068037:South Sudan / Q000453:epidemiology; D014454:Uganda / Q000453:epidemiology
keywords: Africa; Blackflies; Epilepsy; Nodding syndrome; Onchocerca; Simulium