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Evolution of epilepsy prevalence and incidence in a Tanzanian area endemic for onchocerciasis and the potential impact of community-directed treatment with ivermectin: a cross-sectional study and comparison over 28 years
  1. Helena Greter1,
  2. Bruno Mmbando2,
  3. Williams Makunde2,
  4. Mohamed Mnacho3,
  5. William Matuja3,
  6. Advocatus Kakorozya4,
  7. Patrick Suykerbuyk1,
  8. Robert Colebunders1
  1. 1 Global Health Institute, University of Antwerp, Wilrijk, Belgium
  2. 2 National Institute of Medical Research, Tanga Research Centre, Tanga, Tanzania
  3. 3 Department of Neurology, Muhimbili University of Health Sciences, Dar es Salaam, Tanzania
  4. 4 Enhance Tanzania Foundation, Dar es Salaam, Tanzania
  1. Correspondence to Prof Robert Colebunders; robert.colebunders{at}


Introduction Worldwide, there are an estimated 50 million people affected by epilepsy. Its aetiology is manifold, and parasitic infections play an important role, specifically onchocerciasis. In onchocerciasis endemic areas, a distinctive form of epilepsy has been described as nodding syndrome, affecting children and causing nodding seizures, mental retardation and debilitating physical development. Onchocerciasis control programmes using community-directed treatment with ivermectin (CDTI) are implemented in endemic countries. This study is designed to contribute to a better understanding of the linkage between the onset of epilepsy, onchocerciasis and CDTI. Comparing the epidemiological data on epilepsy and onchocerciasis from pre-CDTI and 20 years after its introduction will allow identifying a potential impact of ivermectin on the onset of epilepsy.

Methods and analysis The study will be conducted in the Mahenge highlands in Tanzania. Study site selection is based on an in-depth study on epilepsy in that area dating from 1989. CDTI was introduced in 1997. By a door-to-door approach, the population will be screened for epilepsy using a validated questionnaire. Suspected cases will be invited for a neurological examination for case verification. Onchocerciasis prevalence will be assessed by a rapid epidemiological assessment. As an indicator for ongoing transmission, children younger than 10 years of age will be tested for Ov16 antibodies. Ivermectin use will be assessed at household level. Epilepsy data will be analysed in comparison with the 1989 data to reveal pre-CDTI and post-CDTI prevalence and incidence.

Ethics and dissemination The protocol has received ethical approval from the ethics committees of the University of Antwerp, Belgium, and of the National Institut of Medical Research, Dar es Salaam, Tanzania. The findings will be published in peer-reviewed journals, and presented to the health authorities in Tanzania, at national, regional and village level.

  • tropical medicine
  • parasitology
  • epidemiology
  • infection control

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  • Contributors All listed authors contributed to the development of the study design, essential study documents and study tools. According to their different areas of expertise, the authors critically revised specific parts of this manuscript: HG wrote the manuscript; HG, BM, PS and RC developed the study protocol; WilliamsM, MM, WilliamM developed and approved the neurological study protocol and the survey tools; HG, BM and AK developed the methodology and tools for the digital data collection; HG, BM and RC visited the study sites.

  • Funding This research is embedded in a five-country research project on epilepsy, nodding syndrome and onchocerciasis entitled ‘NSETHIO’, and receives funding from the European Research Council, Advanced Grant (ERC-2014-ADG), grant no. 671055.

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval The protocol has received ethical approval from the ethics committee of the University of Antwerp, Antwerp, Belgium (29 August 2016) and the National Institute of Medical Research (NIMR) ethical committee Dar es Salaam, Tanzania (24 August 2016).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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