Prions is a deadly disease of cattle. It is the cause of Bovine Spongiform Encephalopathy (BSE) or mad-cow disease.
It is not technically a parasitic disease. It is a protein that is produced by a gene from the cow genome. Usually this protein causes no problems. However, in high enough concentrations, the protein will accumulate in the cow’s brain causing plaques. This leads to the neurological problems. The clinical signs include increased aggression and uncoordinated muscle movements. Ultimately the cow will die of BSE.
BSE is an important disease because humans can become infected if they consume contaminated beef.
What’s the solution?
There is only one. You need to euthanize them. Go see Alec the veterinarian for help.