Contents lists available at ScienceDirect Journal of the Neurological Sciences journal homepage: www.elsevier.com/locate/jns Tropical ataxic neuropathy: Findings of a neuroepidemiological survey of Odeda, southwest Nigeria F.M. Otubogun a, ⁎ , R.O. Akinyemi b,c , |A.O. Ogunniyi b,c a Department of Internal Medicine, Federal Medical Centre, Birnin Kebbi, Kebbi, Nigeria b Department of Medicine, University College Hospital, Ibadan, Oyo, Nigeria c Neuroscience and Ageing Research Unit, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria ARTICLE INFO Keywords: Tropical ataxic neuropathy Toxiconutritional disorders Nigeria Africa ABSTRACT Background: Tropical ataxic neuropathy seems to have dwindled in public health importance in Nigeria despite the high consumption of cassava-based meals by a huge proportion of people in local Nigerian communities. Yet a recent report suggest its persistence in the same ethnogeographic setting where it was first reported in Nigeria. Our objective was to investigate the prevalence of tropical ataxic neuropathy in Odeda, Ogun state, southwest Nigeria inhabited by a different ethnic group compared to Epe where the disease was first described. Methods: A two-stage, cross-sectional survey of Odeda local government area for the prevalence and profile of toxiconutritional neurological disorders was carried out between May and June 2015. A screening instrument was applied by trained non - medical interviewers with positive responders further evaluated by a neurologist. Results: 2392 individuals aged 18 years or older were screened and had a mean age of 37.2 ± 16.1 years, were predominantly of Egba Yoruba ethnicity. Thirty nine cases of tropical ataxic neuropathy were diagnosed and crude prevalence rate was 16.3/1000 (95% CI 11.2–21.4/1000). Older age and rural residence were associated with higher prevalence. Distal sensory polyneuropathy was the most common feature whereas sensorineural deafness was the least common finding. Conclusion: This report provides evidence that tropical ataxic neuropathy persists and in a wider geographic spread. Thus tropical ataxic neuropathy still remains a significant public health importance and concerted efforts are required to mitigate or eradicate tropical ataxic neuropathy in southwest Nigeria and other regions of Africa affected by cassava- related toxiconutritional disorders. 1. Introduction The health of developing countries is often synonymous with en- demic and epidemic infectious diseases such as Malaria, Tuberculosis, and Human immunodeficiency virus [1]. One less known class of non- infectious diseases is toxiconutritional disorder. Nutritional amblyopia, epidemic optic neuropathy and peripheral neuropathy of Cuba, Stra- chan's disease, prisoner of war neuropathy and tropical ataxic neuro- pathy(TAN) constitute a spectrum of toxiconutritional disorders with predominantly nervous system involvement which have been described over 100 years ago [2–6]. Are these diseases now medical rarities or curiosities which are no longer relevant or prevalent? A cross-sectional, community-based study conducted almost two decades ago in Ososa, southwest Nigeria suggests otherwise as it reported on the persistence of tropical ataxic neuropathy (TAN) [7]. TAN is a predominantly sensory neuropathy of subacute or chronic onset characterized by impaired light touch, vibration and proprioception, gait ataxia, sensorineural hearing loss, amblyopia, and infrequently muscle weakness and atrophy [8]. Its association with excessive consumption of cassava and in particular chronic cyanide intoxication has been well described in tropical regions of Africa and Americas where cassava products are an important source of calories for over half a billion people [9]. What is common to this study and many older reports on TAN in Nigeria is that they were carried out in predominantly Ijebu Yorubas [7,10]. It is however unclear if TAN persists or even exists in other ethnogeographic regions and its clinical and public health relevance in present times. Persistence of TAN in endemic forms if confirmed especially in areas where previously unreported, is likely to be of public health importance considering the global production and consumption of cassava and cassava products. Hence, possible non-diagnosis, under-diagnosis and misdiagnosis of TAN is likely to translate into significant neurologic https://doi.org/10.1016/j.jns.2019.116434 Received 3 April 2019; Received in revised form 22 July 2019; Accepted 23 August 2019 ⁎ Corresponding author at: Department of Internal Medicine, Federal Medical Centre, Dukku Baracks Road, Birnin Kebbi, Kebbi State, Nigeria. E-mail address: folabogun@gmail.com (F.M. Otubogun). Journal of the Neurological Sciences 405 (2019) 116434 Available online 27 August 2019 0022-510X/ © 2019 Elsevier B.V. All rights reserved. T