Seasonal ataxia: a case report of a disappearing disease

Introduction: Seasonal ataxia is a clinical syndrome of acute cerebellar ataxia which follows ingestion of roasted larvae of Anaphe venata Butler, an alternative protein source consumed in western Nigeria. It was first reported in the 1950s in western Nigeria when it caused a wave of epidemics. This is the first case report of this condition in the literature since 1993.
Case report: We present the case of a 35 year old woman from western Nigeria who was admitted in October 2012 with acute onset of gait instability and bilateral hand tremors, preceded by several episodes of vomiting. She had ingested a meal containing roasted larvae of the African silkworm, 2 hours before the onset of vomiting.
Conclusion: Seasonal ataxia is an important differential diagnosis of acute cerebellar ataxia among the indigenous ethnic population of western Nigeria. It is non-fatal and treatable, with complete resolution of symptoms usually following thiamine therapy.