TSE

=Transmissible Spongiform Encephalopathy=

Transmissible spongiform encephalopathy (TSE) is a prion disease (proteins shaped into a misguided form), first noted in sheep. The disease has been well known for over 250 years, as many goats and sheep had the disease, nicknamed "scrapie" due to the scraping the sheep did against gates to sheer off their own wool. The disease appeared in cows in approximately the 1980s, due to the cows eating from sheep infected with scrapie. The first human cases occurred in the 1990s, due to ingestion of the infected meat. Notably, there was a time delay between the first incidents of BSE (bovine spngiform encephalopathy) and Creutzfeldt-Jacob disease ("mad cow") in humans.

The disease causes brain deterioration over the course of a few months to years. In the animals, the cows and sheep tended to stay away from the herd and constantly scratch at themselves with poles, fences or other objects until their death In the case of humans, personality and mental deterioration occurs, until the death of the patient.

TSE Origin and Transmission
For the most part, the disease begins from corrupted prions transmitting from one creature to another, adapting for each. In humans, CJD is extremely similar to BSE. Both have the corruption of the protein PrPc to PrPsc, the former having mainly alpha-helix regions and is relatively soluble while the latter beta-pleated sheet regions and insoluble. TSE can also be caused by a missense mutation, from a simple sequence of CATGC to CCGGC, TSE is activated in these humans. This change is from a proline to a histine causes larger beta-pleated sheets in the protein molecule, allowing for the disease to spread. In most instances in humans, the disease is mostly the sporadic form which is caused by ingestion of the diseased meat, and only 5-10% is from the genetic variant.

The last version of TSE is spontaneous, in which the disease appears through mutation in a person's normal proteins into prions, and then can become the transmittable variant. In this case, the prions go from cell to cell, infecting the proteinsand causing a large chain reaction.

**Cures, Treatment, and Prevention**

Currently, there are no cured for any form of TSE. Organizations such as the WHO and CDC are working to cure prion diseases but these are a recent discovery in the field of biology, so it will take time for cures to come about. Though preliminary measures can be taken to be sure that the disease does not spread, or at least minimal. These efforts include stronger regulation on cattle and not purchasing or using infected meat. There is also currently no test to analyze DNA to see if an individual is infected with some form of TSE. TSE can also be transmitted from individual to individual, but not through air or touch. The only way for the disease to be transmitted is through bodily fluids or medical instruments, in which for the latter, normal sterilization methods such as boiling do not kill off the prions.