Minamata disease
The first report of Minamata disease originated in Minamata in Kumamoto Prefecture in the year 1956. Many of the earliest patients became insane from the symptoms and in some cases died within a month of being afflicted. After an extensive investigation, the Minamata disease was identified as a heavy metal poisoning, specifically methylmercury poisoning, transmitted by the ingestion of contaminated fish from Minamata Bay. The methylmercury inside the contaminated fish attacked the afflicted patient's central nervous system, which caused a variety of symptoms.