How is this mad cow disease similar to chronic wasting that occurs in deer and elk?
Bovine spongiform encephalopathy (BSE) in cattle and chronic wasting disease (CWD) in deer and elk are both transmissible spongiform encephalopathies (TSEs). TSEs are a group of fatal neurodegenerative diseases that affect both humans and animals. They are caused by the accumulation of abnormal prions, which are misfolded proteins that are infectious and can cause normal prions to misfold, leading to the formation of amyloid plaques and neurodegeneration.
BSE and CWD are similar in several ways:
1. Causative Agent: Both BSE and CWD are caused by abnormal prions. Prions are infectious proteins that differ from viruses and bacteria. They have the ability to transform normally folded prion proteins into abnormal ones.
2. Mode of Transmission: BSE and CWD are primarily transmitted through the ingestion of contaminated feed, food, or water. Direct contact with infected animals or their bodily fluids can also transmit the diseases.
3. Long Incubation Period: Both BSE and CWD have long incubation periods before clinical signs appear. In cattle, the incubation period for BSE can range from several months to several years. In deer and elk, the incubation period for CWD can be several years or even decades.
4. Neurological Symptoms: BSE and CWD affect the central nervous system, leading to progressive neurodegeneration. Clinical signs include abnormal behavior, difficulty in coordination and balance, muscle tremors, and eventually death.
5. Spongy Degeneration: Both diseases cause spongy degeneration of the brain and other parts of the central nervous system. This spongy appearance is a characteristic neuropathological feature of TSEs.
6. Fatal Outcome: BSE and CWD are always fatal. There is no known cure or effective treatment for these diseases.
7. Public Health Concerns: BSE and CWD pose public health risks. BSE in cattle has been linked to variant Creutzfeldt-Jakob disease (vCJD) in humans, a fatal neurodegenerative disorder. CWD has not been reported to affect humans, but there is concern about potential zoonotic transmission.