Epilepsia Verminosa

Epilepsy is a major public health threat in the developing world, with much higher prevalence and incidence rates than those observed in developed countries. At present, one of the most common causes for epilepsy worldwide is the parasitic worm, Taenia solium, and the associated neurocysticercosis (NCC) that may often result from this infestation. Worm infestation was already recognized as a cause of epilepsy by the middle of the 18th century. Helminths and their effects on health were a daily medical concern in the 18th and 19th centuries--with prevailing views ranging from the beneficial effects of the presence of adult worms in the gut, to considering them as culprits for a wide variety of diseases. A number of cases followed longitudinally by various nineteenth-century French physicians showed that there was good reason to believe that the verminous influence on seizures was real, as the expulsion of the T. solium often coincided with a notable amelioration of symptoms. Several theories were proposed to account for how the worms could lead to Epilepsia nervosa, including notions of competition for nutritional resources between the host and the parasite, and irritation of the medulla and of peripheral nerve endings predisposing to epileptiform episodes. Recently, after almost a century of quiet, interest in the neurological effects of helminths has been rekindled, due in part to the growing number of cases in the United States with NCC-related neurological disorders. In this article, we review the history of our understanding of the relationship between seizure disorders and parasitic worms, and we relate this history to contemporary epidemiologic and public health issues in developing countries.