Minamata disease

Abstract

Minamata disease (methylmercury poisoning) was first discovered in 1956 around Minamata Bay, Kumamoto Prefecture, Japan. A second epidemic in Japan occurred in 1965 along the Agano River, Niigata Prefecture. This paper presents a brief review of Minamata disease with an emphasis on the cases found in Kumamoto Prefecture. At autopsy, the most conspicuous destructive lesion in the cerebrum was found in the anterior portions of the calcarine cortex. Less severe but similar lesions may be found in the post-central, pre-central and temporal transverse cortices. Secondary degeneration from primary lesions may be seen in cases with long survival. In the cerebellum, pathological changes occur deep in the hemisphere. The granule cell population was more affected, compared with Purkinje cells. Among peripheral nerves, sensory nerves were more affected than motor nerves. Our recent experimental studies that reveal knowledge of the pathogenesis of methylmercury poisoning will be discussed.