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Edridge AWD, Abd-Elfarag G, Deijs M, Broeks MH, Cristella C, Sie B, Vaz FM, Jans JJM, Calis J, Verhoef H, Demir A, Poppert S, Nickel B, van Dam A, Sebit B, Titulaer MJ, Verweij JJ, de Jong MD, van Gool T, Faragher B, Verhoeven-Duif NM, Elledge SJ, van der Hoek L, Boele van Hensbroek M. Parasitic, bacterial, viral, immune-mediated, metabolic and nutritional factors associated with nodding syndrome. Brain Commun 2023; 5:fcad223. [PMID: 37731906 PMCID: PMC10507744 DOI: 10.1093/braincomms/fcad223] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 06/25/2023] [Accepted: 08/16/2023] [Indexed: 09/22/2023] Open
Abstract
Nodding syndrome is a neglected, disabling and potentially fatal epileptic disorder of unknown aetiology affecting thousands of individuals mostly confined to Eastern sub-Saharan Africa. Previous studies have identified multiple associations-including Onchocerca volvulus, antileiomodin-1 antibodies, vitamin B6 deficiency and measles virus infection-yet, none is proven causal. We conducted a case-control study of children with early-stage nodding syndrome (symptom onset <1 year). Cases and controls were identified through a household survey in the Greater Mundri area in South Sudan. A wide range of parasitic, bacterial, viral, immune-mediated, metabolic and nutritional risk factors was investigated using conventional and state-of-the-art untargeted assays. Associations were examined by multiple logistic regression analysis, and a hypothetical causal model was constructed using structural equation modelling. Of 607 children with nodding syndrome, 72 with early-stage disease were included as cases and matched to 65 household- and 44 community controls. Mansonella perstans infection (odds ratio 7.04, 95% confidence interval 2.28-21.7), Necator americanus infection (odds ratio 2.33, 95% confidence interval 1.02-5.3), higher antimalarial seroreactivity (odds ratio 1.75, 95% confidence interval 1.20-2.57), higher vitamin E concentration (odds ratio 1.53 per standard deviation increase, 95% confidence interval 1.07-2.19) and lower vitamin B12 concentration (odds ratio 0.56 per standard deviation increase, 95% confidence interval 0.36-0.87) were associated with higher odds of nodding syndrome. In a structural equation model, we hypothesized that Mansonella perstans infection, higher vitamin E concentration and fewer viral exposures increased the risk of nodding syndrome while lower vitamin B12 concentration, Necator americanus and malaria infections resulted from having nodding syndrome. We found no evidence that Onchocerca volvulus, antileiomodin-1 antibodies, vitamin B6 and other factors were associated with nodding syndrome. Our results argue against several previous causal hypotheses including Onchocerca volvulus. Instead, nodding syndrome may be caused by a complex interplay between multiple pathogens and nutrient levels. Further studies need to confirm these associations and determine the direction of effect.
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Affiliation(s)
- Arthur W D Edridge
- Amsterdam Centre for Global Child Health, Emma Children’s Hospital,
Amsterdam UMC, Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC,
Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
| | - Gasim Abd-Elfarag
- Amsterdam Centre for Global Child Health, Emma Children’s Hospital,
Amsterdam UMC, Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
- Department of Neurology & Psychiatry, College of Medicine, University
of Juba, P.O. Box 82, Juba, South Sudan
| | - Martin Deijs
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC,
Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
| | - Melissa H Broeks
- Department of Genetics, Section Metabolic Diagnostics, University Medical
Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Cosimo Cristella
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC,
Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
| | - Brandon Sie
- Division of Genetics, Brigham and Women’s Hospital, Howard Hughes Medical
Institute, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School,
Boston, MA 02115, USA
| | - Frédéric M Vaz
- Department of Clinical Chemistry, Amsterdam UMC, Location University of
Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Judith J M Jans
- Department of Genetics, Section Metabolic Diagnostics, University Medical
Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Job Calis
- Amsterdam Centre for Global Child Health, Emma Children’s Hospital,
Amsterdam UMC, Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
- Department of Paediatrics and Child Health, Kamuzu University of Health
Sciences, P.O. Box 95, Blantyre, Malawi
| | - Hans Verhoef
- Division of Human Nutrition and Health, Wageningen
University, 6701 AR Wageningen, The Netherlands
| | - Ayse Demir
- Laboratory for Clinical Chemistry and Hematology, Meander Medical
Centre, 3813 TZ Amersfoort, The Netherlands
| | - Sven Poppert
- Diagnostic Centre, Swiss Tropical and Public Health
Institute, University of Basel, 4123 Allschwil,
Switzerland
- University of Basel, 4056 Basel,
Switzerland
| | - Beatrice Nickel
- Diagnostic Centre, Swiss Tropical and Public Health
Institute, University of Basel, 4123 Allschwil,
Switzerland
- University of Basel, 4056 Basel,
Switzerland
| | - Alje van Dam
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC,
Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
| | - Boy Sebit
- Department of Neurology & Psychiatry, College of Medicine, University
of Juba, P.O. Box 82, Juba, South Sudan
| | - Maarten J Titulaer
- Department of Neurology, Erasmus MC University Medical
Center, 3000 CA Rotterdam, The Netherlands
| | - Jaco J Verweij
- Microvida Laboratory for Medical Microbiology and Immunology,
Elisabeth-Tweesteden Hospital, 5022 GC Tilburg,
The Netherlands
| | - Menno D de Jong
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC,
Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
| | - Tom van Gool
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC,
Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
| | - Brian Faragher
- Department of Clinical Sciences, Liverpool School of Tropical
Medicine, Liverpool L3 5QA, UK
| | - Nanda M Verhoeven-Duif
- Department of Genetics, Section Metabolic Diagnostics, University Medical
Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Stephen J Elledge
- Division of Genetics, Brigham and Women’s Hospital, Howard Hughes Medical
Institute, Boston, MA 02115, USA
| | - Lia van der Hoek
- Department of Medical Microbiology and Infection Prevention, Amsterdam UMC,
Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
| | - Michael Boele van Hensbroek
- Amsterdam Centre for Global Child Health, Emma Children’s Hospital,
Amsterdam UMC, Location University of Amsterdam, 1105 AZ
Amsterdam, The Netherlands
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Raimon S, Dusabimana A, Abd-Elfarag G, Okaro S, Carter JY, Newton CR, Logora MY, Colebunders R. High Prevalence of Epilepsy in an Onchocerciasis-Endemic Area in Mvolo County, South Sudan: A Door-To-Door Survey. Pathogens 2021; 10:pathogens10050599. [PMID: 34068976 PMCID: PMC8157079 DOI: 10.3390/pathogens10050599] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/01/2021] [Accepted: 05/11/2021] [Indexed: 11/25/2022] Open
Abstract
In June 2020, a door-to-door household survey was conducted in Mvolo County, an onchocerciasis-endemic area in South Sudan. A total of 2357 households containing 15,699 individuals agreed to participate in the study. Of these, 5046 (32.1%, 95% CI: 31.4–32.9%) had skin itching and 445 (2.8%, 95% CI: 2.6–3.1%) were blind. An epilepsy screening questionnaire identified 813 (5.1%) persons suspected of having epilepsy. Of them, 804 (98.9%) were seen by a medical doctor, and in 798 (98.1%) the diagnosis of epilepsy was confirmed. The overall epilepsy prevalence was 50.8/1000 (95% CI: 47.6–54.4/1000), while the prevalence of nodding syndrome was 22.4/1000 (95% CI: 20.1–24.9/1000). Younger age, being male, skin itching, blindness, and living in a neighbourhood or village close to the Naam River were risk factors for epilepsy. The annual incidence of epilepsy was 82.8/100,000 (95% CI: 44.1–141.6/100,000). Among children 7–9 years old without epilepsy, 34% were Ov16 seropositive, suggesting high ongoing Onchocerca volvulus transmission, but only 41.9% of them took ivermectin during the last mass distribution. In conclusion, a high prevalence and incidence of epilepsy was observed in Mvolo, South Sudan. Strengthening of the onchocerciasis elimination programme is urgently needed in order to prevent epilepsy in this region.
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Affiliation(s)
- Stephen Raimon
- Amref Health Africa, Juba P.O. Box 410, South Sudan; (S.R.); (S.O.)
| | - Alfred Dusabimana
- Global Health Institute, University of Antwerp, Kinsbergen Centrum, Doornstraat 331, 2610 Antwerp, Belgium;
| | - Gasim Abd-Elfarag
- Global Child Health Group, Department of Paediatrics and Department of Global Health Academic Medical Center, University of Amsterdam, 1105 BP Amsterdam, The Netherlands;
- Amsterdam Institute for Global Health and Development, 1105 BP Amsterdam, The Netherlands
| | - Samuel Okaro
- Amref Health Africa, Juba P.O. Box 410, South Sudan; (S.R.); (S.O.)
| | - Jane Y. Carter
- Amref Health Africa Headquarters, Nairobi P.O. Box 30125, Kenya;
| | | | - Makoy Yibi Logora
- Neglected Tropical Diseases Unit, Ministry of Health, Juba P.O. Box 410, South Sudan;
| | - Robert Colebunders
- Global Health Institute, University of Antwerp, Kinsbergen Centrum, Doornstraat 331, 2610 Antwerp, Belgium;
- Correspondence:
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