Question

What are the known diseases caused by abnormal prions?

Short answer

CJD, VPSPr, FFI, Kuru, BSE, Scrapie, CWD

Step-by-step solution

Understand Prions

Prions are misfolded proteins that can cause other proteins to also misfold, leading to disease.

Identify Human Diseases

The main human diseases caused by prions include Creutzfeldt-Jakob Disease (CJD), Variably Protease-Sensitive Prionopathy (VPSPr), Fatal Familial Insomnia (FFI), and Kuru.

Identify Animal Diseases

In animals, known prion diseases are Bovine Spongiform Encephalopathy (BSE) commonly known as 'mad cow disease', Scrapie in sheep, and Chronic Wasting Disease (CWD) in deer and elk.

List of Diseases

Summarize the diseases in a list format: 1. Creutzfeldt-Jakob Disease (CJD)2. Variably Protease-Sensitive Prionopathy (VPSPr)3. Fatal Familial Insomnia (FFI)4. Kuru5. Bovine Spongiform Encephalopathy (BSE)6. Scrapie7. Chronic Wasting Disease (CWD)

Key concepts

Prions

Prions are a unique type of infectious agent. Unlike bacteria or viruses, they don't contain DNA or RNA. Instead, prions are misfolded proteins. They can trigger normal proteins in the brain to fold abnormally. This chain reaction leads to brain damage and neurodegeneration.
Scientists believe that prions are the cause of several degenerative brain diseases. These diseases are collectively known as prion diseases. Prion infections are typically fatal because there are no known treatments. Understanding prions helps us understand more about related diseases and find possible treatments in the future.

Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob Disease (CJD) is one of the most well-known prion diseases affecting humans. It leads to rapid neurodegeneration, where the brain tissue deteriorates quickly. CJD is characterized by symptoms like:

• Memory loss
• Behavioral changes
• Lack of coordination and vision problems
• Eventually, severe mental impairment

There are different types of CJD:

• Sporadic CJD: This occurs without any known cause and accounts for the majority of cases.
• Hereditary CJD: This is caused by a genetic mutation.
• Acquired CJD: This type is contracted through exposure to infected tissue, such as during medical procedures or eating contaminated meat.

The disease progresses rapidly, and patients often do not survive more than a year after symptoms appear.

Fatal Familial Insomnia

Fatal Familial Insomnia (FFI) is a rare genetic disorder. It is also caused by abnormal prions and affects the thalamus—the part of the brain that regulates sleep.
FFI leads to an inability to sleep, which intensifies over time. Symptoms include:

• Insomnia
• Involuntary muscle movements
• Difficulty walking
• Dementia
• Hallucinations

It is a hereditary disease, meaning that it is passed down within families through a specific genetic mutation. Currently, there is no cure for FFI, and it is ultimately fatal.

Bovine Spongiform Encephalopathy

Bovine Spongiform Encephalopathy (BSE), commonly known as 'mad cow disease,' is a prion disease that affects cattle.
The disease is marked by changes in the behavior of cows, such as:

• Increased aggression
• Uncoordinated movements
• Weight loss
• Decreased milk production

BSE can be transmitted to humans through the consumption of infected bovine material, leading to a human-form prion disease called variant Creutzfeldt-Jakob disease (vCJD). Since diagnosing and controlling BSE is essential for public health, there are strict regulations concerning cattle farming and meat processing.

Scrapie

Scrapie is a prion disease that affects sheep and goats. It gets its name because infected animals tend to scrape themselves against surfaces due to severe itching.
Other symptoms include:

• Changes in behavior
• Loss of coordination
• Weakened wool and weight loss
• Eventually, severe neurological decline

Scrapie has been known for over 200 years and mainly concerns the livestock industry. While it is fatal for animals, there is no evidence to suggest that scrapie can be transmitted to humans.

Chronic Wasting Disease

Chronic Wasting Disease (CWD) affects deer, elk, and moose. It is a prion disease similar to BSE and scrapie but specific to these wildlife species.
Animals with CWD show symptoms such as:

• Dramatic weight loss
• Staggering
• Excessive thirst and urination
• Isolation from the herd

CWD is a growing concern among wildlife managers as it has spread to various parts of North America. There is no evidence to suggest that CWD is transmissible to humans, but research is ongoing.
Managing CWD involves monitoring wildlife, controlling movement, and setting hunting regulations to prevent the spread.