title: Nodding syndrome-a new hypothesis and new direction for research.
abstract: Nodding syndrome (NS) is an unexplained neurological illness that mainly affects children aged between 5 and 15 years. NS has so far been reported from South Sudan, northern Uganda, and Tanzania, but in spite of extensive investigations, the aetiology remains unknown. We hypothesize that blackflies (Diptera: Simuliidae) infected with Onchocerca volvulus microfilariae may also transmit another pathogen. This may be a novel neurotropic virus or an endosymbiont of the microfilariae, which causes not only NS, but also epilepsy without nodding. This hypothesis addresses many of the questions about NS that researchers have previously been unable to answer. An argument in favour of the hypothesis is the fact that in Uganda, the number of new NS cases decreased (with no new cases reported since 2013) after ivermectin coverage was increased and with the implementation of a programme of aerial spraying and larviciding of the large rivers where blackflies were breeding. If confirmed, our hypothesis will enable new strategies to control NS outbreaks.
authors.affiliation: Department of Epidemiology and Social Medicine, University of Antwerp, Antwerp, Belgium; Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium. Electronic address: bcoleb@itg.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: WHO Uganda, Disease Prevention and Control, Uganda.
authors.forename: Miriam
authors.initials: M
authors.lastname: Nanyunja
authors.affiliation: Ministry of Health, Uganda.
authors.forename: Joseph Francis
authors.initials: JF
authors.lastname: Wamala
authors.affiliation: Department of Neurology, Epidemiology and Biostatistics, Erasmus Medical Centre, Rotterdam, Netherlands.
authors.forename: Marieke
authors.initials: M
authors.lastname: van Oijen
mesh_terms: D000293:Adolescent; D000818:Animals; D002648:Child; D002675:Child, Preschool; D004827:Epilepsy / Q000453:epidemiology* / Q000469:parasitology; D006801:Humans; D008842:Microfilariae / Q000302:isolation & purification; D064128:Nodding Syndrome / Q000453:epidemiology* / Q000209:etiology / Q000469:parasitology; D009855:Onchocerciasis / Q000453:epidemiology* / Q000469:parasitology; D015995:Prevalence; D012843:Simuliidae / Q000469:parasitology; D013397:Sudan / Q000453:epidemiology; D013636:Tanzania / Q000453:epidemiology; D014454:Uganda / Q000453:epidemiology
keywords: Blackflies; Epilepsy; Nodding syndrome; Onchocerca volvulus; Onchocerciasis; South Sudan; Tanzania; Uganda