What Is a Coronavirus? How Does a Vrus Work?

This type of virus can affect both animals and humans and causes diseases in the respiratory system

Coronavirus in Spain: Last-minute, life

Coronaviruses are a type of virus. They are so named because their surface is covered by a series of proteins that, seen under a microscope, seem to create a crown around them.

This family of viruses was discovered during the 1960s. Most affect only animals, although some coronaviruses can be passed from animals to people through a process known as zoonotic transmission.

Coronaviruses affect the respiratory system, causing lung problems and difficulty breathing. Some only cause a cold with mild symptoms, while others can cause pneumonia and more serious infections, and even death.

There are many kinds of coronaviruses. Scientists have detected up to seven types of coronaviruses that can infect humans.

MERS and SARS

In addition to SARS-CoV-2, the coronavirus that causes COVID-19 disease, the World Health Organization (WHO) has detected two other types of coronaviruses that cause serious illness in humans.

The MERS-CoV coronavirus causes Middle East respiratory syndrome (MERS). This disease was first detected in 2012 in Saudi Arabia, where 80% of cases have been reported. The virus is believed to have spread to humans through contact with infected dromedaries.

MERS-CoV has a much higher case fatality rate than the new coronavirus (35% of cases die), but it is much more difficult to spread between people. Since its appearance, less than 3,000 cases have been detected worldwide.

Although the disease is controlled, new cases of MERS still appear today, especially in poor regions that do not have many health resources.

Furthermore, the SARS-CoV coronavirus causes severe acute respiratory syndrome (SARS). The first cases were detected in 2002 in China, from where the virus spread to thirty countries. The virus is believed to have spread to humans from a civet, a type of wild mammal.

In July 2003, the WHO considered the disease to be controlled, and no further cases have been reported since. It affected about 8,000 people worldwide (with the lethality of 10%).

The main symptoms of these diseases are fever, cough, and shortness of breath. Like SARS-CoV-2 coronavirus, MERS-CoV and SARS-Cov affect more elderly people or those with previous illnesses.

A new SARS

The new coronavirus was first detected inside the Chinese town of Wuhan in December 2019. Some people showed symptoms of pneumonia, but doctors did not recognize the virus.

It was called SARS-CoV-2 because it was very similar to the other coronavirus that appeared in China in 2002. The difference between these two coronaviruses is that the new coronavirus has a much higher infection capacity than the previous one.

In just over three months, it has infected more than 200,000 people and spread to more than 100 countries, while SARS-CoV infected just over 8,000 people before the disease was controlled.

The SARS-CoV-2 coronavirus is believed to have been transmitted from a bat to a pangolin, and from there to humans.

How does a virus work?

What is a virus? What types are there? How do they reproduce and transmit from one organism to another?

A virus is an infectious agent 100 times smaller than a cell, so it can only be seen through an electron microscope. The word comes from the Latin virus, which means "toxin" or "poison".

Viruses are at the limit of what could be considered a living being, because they need the cell of another living being to live: it can be the cell of an animal, a plant or a bacterium (bacteria are single-celled organisms).

Once in the body that serves as a host, the virus infects its cells and multiplies to survive.
There are tens of millions of types of viruses, which have one-of-a-kind paperwork and have an effect on one-of-a-kind forms of cells, so that they can purpose exclusive diseases. For example, the poliovirus affects the nervous system and mobility, while the coronavirus affects the lungs and respiratory system.

How a virus works

The structure of a virus is quite simple: it has a genome nucleus, which defines the characteristics of the virus and how it multiplies, and a protein envelope called a “capsid”.

Viruses do not have cytoplasm or ribosomes (elements necessary to form a cell), so they cannot multiply on their own and need to infect another organism's cell to do so.

When the virus infects a cell, it multiplies and releases more viral agents so that they infect other cells and thus spread throughout the body of the host organism.

Viruses are spread by direct contact, through body fluids (blood, saliva, semen) or secretions (urine, feces). People who touch infected objects or animals can also become infected. Therefore, in an epidemic, it is important to maintain a high degree of hygiene.

The ‘memory’ of vaccines

Just as antibiotics attack the cell membrane of bacteria, these types of drugs do not work to treat viruses (because they do not have the same structure as bacteria).

To fight viruses, we need vaccines, which allow the immune system to recognize the virus as an intruder and destroy it.

Vaccines create a kind of memory against the virus. Thus, each time it enters our body, immune cells recognize the proteins that coat the virus and act against it.

The problem is that viruses have a great capacity for mutation: the protein envelope can change and "deceive" the immune system, which stops recognizing it as a harmful element and does not react. This is why viruses are so resistant.

Since the first vaccine was created in the late 18th century, vaccines have been developed for diseases such as rabies, polio, yellow fever, tuberculosis, or measles.

Global viruses

There are viruses that do not cause any disease, while others can be fatal.

One of  The most widespread viruses is influenza, responsible for the flu. There are different types of influenza, which mutates from year to year: that is why, even if a vaccine is found, there is always the flu because of new forms of the virus appear.

Yellow fever is caused by a virus that is transmitted by a mosquito bite. If you don't have the right treatment, it can be fatal. It is an endemic disease in Africa and Latin America, where it is very difficult to eradicate it due to the lack of economic resources, sanitation, and campaigns that promote hygienic and sanitary habits.

HIV the virus is one of the best known because it causes acquired immunodeficiency syndrome (AIDS). Since it was first detected in 1980, more than 35 million people are estimated to have died of AIDS. A vaccine to prevent the spread has not yet been found, but there are treatments to prevent the virus from evolving to the most advanced stage.