Minamata disease

Minamata disease is a neurological disease caused by severe mercury poisoning, presenting with ataxia, numbness in the hands and feet, general muscle weakness, loss of peripheral vision, and damage to hearing and speech. In severe cases insanity, paralysis, coma and death follow within weeks, and a congenital form affecting infants displays microcephaly and extensive cerebral damage resembling cerebral palsy. The disease was discovered in Minamata city, Kumamoto Prefecture, Japan, in 1956, stemming from methylmercury in industrial wastewater from a chemical factory owned by the Chisso Corporation that was discharged from 1932 to 1968 and bioaccumulated in fish and shellfish in Minamata Bay. By March 2001, 2,265 people had been officially recognized as having Minamata disease. A second outbreak occurred in Niigata Prefecture in 1965, and both are classified among Japan's Four Big Pollution Diseases.