Where do coronaviruses come from and why are they so dangerous?

The total number of coronavirus infected 2019-nCoV in China is approaching two thousand. The number of deaths is also growing – there are already more than 80 of them.

The type of virus that is currently experiencing an outbreak in China is well known to doctors.

It belongs to the family of so-called coronaviruses that previously caused outbreaks of several diseases – for example, the epidemic of severe acute respiratory syndrome (Sars) in 2003, as well as the Middle East respiratory syndrome (Mers) in 2012. In the case of the first virus, 9% of all infected died, and during the second epidemic, 35% of those who died.

We explain why outbreaks of these viruses occur suddenly and why they are so dangerous.

Where do dangerous coronaviruses come from?

The carriers of the viruses that caused the outbreak of Sars, Mers, and the 2019-nCoV coronavirus are thought to be not animals, but animals. They are carriers of many viruses dangerous to humans, but cases of human infection directly from animals, fortunately, are quite rare.

“Most often there is a so-called species barrier, and it is usually insurmountable for a virus,” says Andrew Easton of the University of Warwick.

“But if someone has weakened immunity or there is some other factor that allows the virus to move from animal to human, this rare case of infection can occur,” the scientist says.

The danger is most often associated with an unusual mutation of the virus.

“As a rule, the virus must change in a certain way so that it has the opportunity to live and grow in a new, unusual environment,” says the scientist.

In rare cases, when the coronavirus is transmitted to humans, things can take an extremely serious turn.

It is worth remembering that not all coronaviruses are very dangerous: a person constantly encounters their less aggressive varieties. But those that are passed from one species to another can be a big threat.

Why are “interspecific” coronaviruses so dangerous for humans?

“When a virus is transmitted from one species to another, it is impossible to predict how events will develop. It is not unusual for a virus to find a niche in a new environment. And in the early stages of this process, the virus can be very strong,” says Andrew Easton.

The fact is that when a virus suddenly passes from an animal to a person, the human immune system is not ready to deal with this particular virus, since it has never encountered it before. And a person is very vulnerable to such viruses.

A similar problem occurs when different types of influenza viruses begin to be transmitted from one species to another.

The deadliest flu pandemic occurred in 1918-19. It is believed that a person has contracted this type of bird flu. Then the victims of the “Spanish” were up to 50 million people.

There is no clear evidence that the current coronavirus can cause such a severe epidemic, however, previous cases of human infection from animals cause doctors to be on their guard.

Can coronavirus spread very quickly?

The good news is that in the initial stages after transmission from an animal to a person, the virus cannot spread quickly from person to person. “This is another barrier, another obstacle the virus needs to overcome,” says Andrew Easton.

However, then the virus can be transmitted very quickly, and if this happens, the situation becomes extremely serious.

“Viruses, including coronaviruses, mutate at a fairly high speed,” the scientist emphasizes.

Further mutations of the virus can allow it to spread among people very quickly – this means that the epidemic can cover a large area in a fairly short time.

This happened with the current outbreak of coronavirus in China, so it is necessary to take measures as soon as possible to prevent its spread.

“If a person with a weakened immune system becomes infected with them, the reason may be that he has a disease that has made him more vulnerable. However, a healthy person may not become infected. Some viruses are transmitted very quickly, and some, on the contrary, are very slow. One of the questions that needs to be answered is to which type this new coronavirus belongs, “says Professor Easton.

What to do when the virus spreads?

The bad news is that the spread of the virus can not always be stopped with medication. “There are very few effective antiviral drugs,” the expert warns.

There are a number of other fairly simple and effective measures, such as washing your hands and using medical masks.

“The basic hygiene rules are very useful. They help protect ourselves and others from many diseases, and at the moment this is probably the only affordable and effective means of control, because in the very near future we will not have any drugs for this virus,” says scientist.

It is also very important how to treat those who have already become infected.

“Another important aspect is to identify infected people as quickly as possible so that they can be helped and thus try to reduce the likelihood of spreading the infection,” says Andrew Easton.

Fortunately, after outbreaks of the Sars and Mers coronaviruses, mechanisms of action at the international level to prevent the spread of the disease have been developed.

“We’ve already seen these cases several times, and now that you need to make certain decisions, it’s faster,” says Andrew Easton.

Doctors hope that thanks to the conclusions made after previous coronaviruses, the current outbreak – and all subsequent ones – will be less dangerous for human life and health.

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