Dancing Cat Syndrome

Mercury is a heavy metal of known toxicity, noted for inducing the public health disasters in Minamata Bay, Japan[1]. Human toxicity varies with the form of mercury, the dose and the rate of exposure.

Mercury exposure can lead to developmental problems in the brain, which can also affect physical functions such as motor skills. Some children who are exposed to mercury at a young age may develop learning disabilities. Adults with mercury poisoning may have permanent brain and kidney damage. Circulatory failure is another possible type of complication.

Mercury is most notable for its neurological effects. High amounts of mercury can lead to long-term and sometimes permanent neurological changes as is shown by the so-called Mad Hatter Syndrome. Also early mentions of Morgellons Syndrome, observed in the the Languedoc in southern France in the early 1600s, can be traced back to cinnabar, used as a textile dye[2]. Cinnabar is  a bright red mineral consisting of mercuric sulphide.

But, if mercury is toxic to humans, it must also be so for animals, like cats. Minamata disease (in humans) was first discovered in the city of Minamata in Japan, in 1956. It was caused by the release of huge amounts of methylmercury in the industrial wastewater from the Chisso Corporation's chemical factory, which continued from 1932 to 1968. This highly toxic chemical bioaccumulated in shellfish and fish in Minamata Bay and the adjoining Shiranui Sea. When consumed by the local population, it resulted in mercury poisoning, leading to at least 1,784 patients who died. There was also an abnormally high frequency of cerebral palsy and other infantile disorders in the Minamata area.

While death of cats, dogs, pigs and humans continued for 36 years, both the government and company did little to prevent the pollution. The neurological effects were severe enough in cats that they came to be named as having 'Dancing Cat Syndrome'.

[1] Environmental Health Department, Ministry of the Environment. Minimata Disease: The History and Measures. Tokyo, Japan: Ministry of the Environment, Government of Japan - 2002
[2] Keleher: Patterns in Early Morgellons Disease in Considered as Effects of Mercury Exposure in Morgellons Research - 200. See here.