FOOD SHORTAGES AND AN EPIDEMIC OF OPTIC AND PERIPHERAL NEUROPATHY IN CUBA

From late 1991 to mid-1993, cases of optic neuropathy of unknown etiol ogy, which first appeared in unusual numbers in a western province of Cuba, spread and multiplied throughout the island. The dominant sympto ms changed, becoming increasingly those of peripheral neuropathy. Inci dence rates peaked in April 1993. An estimated 50,000 cases were repor ted. The majority were adult men and women (aged about 25-65), with co mparatively few children or elderly people being affected. The cause h as yet to be delineated. However, food shortages and radical changes i n diet resulting from the longstanding US trade embargo and the recent loss of Eastern Europe as Cuba's trading partner have compromised nut ritional status, especially B-vitamin sufficiency, and appear to be re lated to the neuropathic illnesses. In April 1993, the Cuban governmen t began distributing vitamin supplements to every citizen. Causal hypo theses include tobacco-alcohol or ''nutritional'' amblyopia; cyanide t oxicity from cassava; toxic legumes introduced as supplements to scarc e flour; other toxins, for example pesticides, or a ''blue mold'' on t obacco; enterovirus; and a hereditary enzyme deficiency in affected pe rsons. None of these factors appears to be present in all cases, but i t is generally believed that an interaction of some toxin or toxins, i n combination with nutritional deficiency, is likely to be the major c ause.