Wasting diseases of the Brain.
Bovine Spongiform Encephalopathy (BSE) in cows and Scrapie in sheep are animal-borne Transmissible Spongiform Encephalopathies (TSEs). The diseases eventually cause the brain matter of the animals to waste away. Currently there are no inoculations or cures for BSE or Scrapie – once contracted, the animal will eventually die. TSE’s are slow moving diseases – animals are typically infected for years before they begin showing symptoms.
Prions, misfolded proteins.
Proteins are chains of amino acids that are an essential part of all living organisms, especially as structural components of body tissues. Proteins that misfold as they replicate become prions, the infectious agent that causes the TSEs in animals and humans. Prions continue to replicate and over time reach sufficient density to cause neurological damage in the infected animal and eventually cause the animal’s death.
A hardy, transmittable disease.
Prions can occur naturally in an animal and can also be contracted from another animal or even from feed or plants. Animals shed prions in their saliva, urine and feces. Prions can be transmitted from animal to animal through nose to nose contact or licking. Prions are resistant to environmental factors; studies have show that prions can live for several years after being discharged by an animal. Prions in the soil can also be absorbed into plants, for example alfalfa, and then infect an animal that consumes the plant. One infected animal in a herd can cause the disease to spread throughout the herd; every time the animal urinates it sheds prions that can infect other animals.