Transmissible mink encephalopathy


Transmissible mink encephalopathy is a rare sporadic disease that affects the central nervous system of ranch-raised adult mink. It is a transmissible spongiform encephalopathy, caused by proteins called prions.

Clinical signs

This illness has a minimum incubation period of 7 months with a maximum of 12 months. This disease results in mortality of adult animals.
Clinical signs of TME include the characteristic behavioural changes such as confusion, loss of cleanliness, and aimless circling. An affected animal shows signs of weight loss, might develop matted fur, hindquarter ataxia, and its tail arched over its back. Seizures may very rarely occur. Near-death stages include the animal showing signs of drowsiness and unresponsiveness.

Diagnosis

Currently, no tests are available to detect signs of this illness in live animals. However, veterinary pathologists can confirm this illness by microscopic examination of the brain tissue in animals suspected to have died of this disease, where they expect to detect areas of distinct sponge-like formations, or by the identification of the prion protein in these tissue samples.

History

Transmissible mink encephalopathy was first noticed in 1947 on a mink farm in the United States, in Brown County, Wisconsin, but the disease was not reported in the scientific literature until 1965. The most recent outbreak occurred in 1985, on a farm in the town of Stetsonville, also in Wisconsin. Outbreaks of TME have also occurred in Canada, Finland, Germany, and the former Soviet Union.