On April 21, 1956, a five year-old girl was examined at the Chisso Corporations factory hospital in Minamata, Kumamoto, Japan, a town on the west coast of the southern island of Kyūshū. The physicians were puzzled by her symptoms: difficulty walking, difficulty speaking and convulsions. Two days later her younger sister also began to exhibit the same symptoms and she too was hospitalised. The girls mother informed doctors that her neighbours daughter was also experiencing similar problems. After a house-to-house investigation eight further patients were discovered and hospitalised. On May 1, the hospital director reported to the local public health office the discovery of an epidemic of an unknown disease of the central nervous system, marking the official discovery of Minamata disease. To investigate the epidemic, the city government and various medical practitioners formed the Strange Disease Countermeasures Committee (奇病対策委員会 Kibyō Taisaku Iinkai?) at the end of May 1956. Owing to the localised nature of the disease, it was suspected to be contagious and as a precaution patients were isolated and their homes disinfected. Although contagion was later disproved, this initial response contributed to the stigmatisation and discrimination experienced by Minamata victims from the local community. During its investigations, the committee uncovered surprising anecdotal evidence of the strange behaviour of cats and other wildlife in the areas surrounding patients homes. From around 1950 onward, cats had been seen to have convulsions, go mad and die. Locals called it the cat dancing disease (猫踊り病 neko odori byō?), owing to their erratic movement. Crows had fallen from the sky, seaweed no longer grew on the sea bed and fish floated dead on the surface of the sea. As the extent of the outbreak was understood, the committee invited researchers from Kumamoto University to help in the research effort. The Kumamoto University Research Group was formed on August 24, 1956. Researchers from the School of Medicine began visiting Minamata regularly and admitted patients to the university hospital for detailed examinations. A more complete picture of the symptoms exhibited by patients was gradually uncovered. The disease developed without any prior warning, with patients complaining of a loss of sensation and numbness in their hands and feet. They became unable to grasp small objects or fasten buttons. They could not run or walk without stumbling, their voices changed in pitch and many patients complained of difficulties seeing, hearing and swallowing. In general these symptoms deteriorated and were followed by severe convulsions, coma and eventually death. By October 1956, 40 patients had been discovered, 14 of whom had died: an alarming mortality rate of 35%. Finding the cause Researchers from Kumamoto University also began to focus on the cause of the strange disease. They found that the victims, often members of the same family, were clustered in fishing hamlets along the shore of Minamata Bay. The staple food of victims was invariably fish and shellfish from Minamata Bay. The cats in the local area, who tended to eat scraps from the family table, had died with symptoms similar to those now discovered in humans. This led the researchers to believe that the outbreak was caused by some kind of food poisoning, with contaminated fish and shellfish being the prime suspects. On November 4 the research group announced its initial findings: Minamata disease is rather considered to be poisoning by a heavy metal... presumably it enters the human body mainly through fish and shellfish. Mercury Poisoning in Minamata Bay, Japan.
Posted on: Tue, 07 Oct 2014 07:48:47 +0000
Trending Topics
Recently Viewed Topics
© 2015