Why do cows get mad cow disease? what is the reason

Causes of Mad Cow Disease

The cause of mad cow disease is prion, which is a kind of protein, which exists in the human body. Moreover, the secondary structure of this protein has two configurations: a (alpha) and b (beta). The normal configuration is the a configuration, but once the b configuration protein appears, it will trigger the conversion of other a configuration proteins into b configuration protein. The b-configuration protein has no biological function, and the disease that produces amyloid is mad cow disease.

The name of mad cow disease is “bovine spongiform encephalopathy. It is a progressive and fatal central nervous system disease that occurs in cattle. The symptoms are similar to sheep pruritus. It is commonly known as “mad cow disease” and belongs to human and animal infectious spongiform encephalopathy. A kind of. Its histopathological feature is that the neurons in the brain tissue of sick cattle are vacuolated, forming clear holes, which are spongy under the microscope, so it is called spongiform encephalopathy. Kreuzfeldt-Jacob The disease is a common type of transmissible central nervous system degeneration. Creutzfeldt first reported 1 necropsy case that resembled multiple sclerosis in 1920. Jakob reported 5 similar cases from 1921 to 1923.

In 1923 Spielmayer named it Kreuzfeldt-Jacob disease. In 1929 it was called presenile cortical striatal degeneration. It was called cortical striatal spinal cord degeneration in 1940. The disease usually develops after middle age, with symptoms of progressive dementia, myoclonus, pyramidal tract or extrapyramidal injury as the main clinical manifestations, and death within a few months to 1 year. Pathologically, the main changes are cerebral spongiform degeneration, nerve cell shedding, and astrocyte proliferation. Exist widely in countries all over the world.

Factors of human infection with mad cow disease

1. Eating beef and its products infected with mad cow disease can also cause infection, especially meat removed from the spine (generally German beef sausages are made of this kind of meat);

2. In addition to plant raw materials, some cosmetics also use animal raw materials, so cosmetics may also contain mad cow disease virus (the organs or tissues of cattle and sheep used in cosmetics are: placenta, amniotic fluid, collagen, brain sugar) ;

3. Some scientists believe that the cause of the mutation of “mad cow disease” into “Creut-Jakob disease” in humans is not because of eating beef infected with mad cow disease, but directly caused by environmental pollution. It is believed that excessive metal manganese content in the environment may be the cause of “mad cow disease” and “Creut-Jakoff disease”.

At present, there is no effective treatment method for the treatment of mad cow disease, only the prevention and control of the spread of this type of virus in livestock. Once a cow is found to be infected with mad cow disease, it can only be resolutely slaughtered and incinerated and buried. However, there are also views that even if the cattle infected with BSE are incinerated, the ashes still contain BSE virus. If the ashes are dumped in the dumping area, the virus may be spread.

At present, it is still unclear how the virus is transmitted among livestock and how it is transmitted to humans.

Prevention and treatment of mad cow disease

The University of Munich announced on December 1 that in collaboration with researchers from the University of Bonn and the Max Planck Institute, a substance was found in the brain protein molecules of experimental mice infected with Scrapie virus. This substance can significantly extend The life of an infected laboratory mouse can be made into a vaccine to prevent and treat mad cow disease. Scrapie virus is a variant of mad cow disease virus and human Creutzfeldt-Jakob virus.

The virus-carrying protein molecules that cause mad cow disease can infect healthy protein molecules in the brain, causing a chain reaction and destroying brain tissue. A cow suffering from mad cow disease will quickly die due to damage to the body and brain tissue. However, the researchers found in experimental mice infected with Scrapie virus that even if there are no healthy protein molecules in the brain tissue of the experimental mice, they can still survive well. Based on this, the researchers extracted this special substance from the brain cells of experimental mice.

Researchers at the University of Munich said that vaccines made with this substance can effectively prevent mad cow disease, but whether it can be used in humans to prevent and treat Creutzfeldt-Jakob disease needs in-depth research.

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