Introduction: The authors describes the past eight years, since an epidemic started in Cuba which mainly affected the nervous system, particularly the optic nerve and the peripheral nerves. It is thought to have been the biggest epidemic involving the nervous system this century, although there may be over-diagnosis. The cause is controversial but is probably nutritional imbalance with additional toxic elements also in some cases. At the present time the continuous, low, notification of new cases means that it is endemic.
Development: In this paper we consider the clinical and electrophysiological aspects characteristic of the disorder, the degree of involvement, evolution, incidence and annual follow-up of cases from 1992 to date and their differential diagnosis. We describe the national programme of healthcare for control of the disease in Cuba, the measures designed to reduce the number of patients, most of the results of clinical and epidemiological studies and the possible causes. We also discuss the most likely physiopathological hypotheses.