Contents
In line with its mission, the Editorial Board of MedTvoiLokony makes every effort to provide reliable medical content supported by the latest scientific knowledge. The additional flag “Checked Content” indicates that the article has been reviewed by or written directly by a physician. This two-step verification: a medical journalist and a doctor allows us to provide the highest quality content in line with current medical knowledge.
Our commitment in this area has been appreciated, among others, by by the Association of Journalists for Health, which awarded the Editorial Board of MedTvoiLokony with the honorary title of the Great Educator.
We know for sure that the SARS-CoV-2 coronavirus comes from animals, it is not known only that 100 percent. certainly from what. Bats are probably the primary host, but humans may have caught the infection from intermediaries such as pangolins. COVID-19 is not the first zoonotic disease to wreak havoc on humans. Why are these types of infections so dangerous for us?
Zoonoses That Decimated People – COVID-19 isn’t the first
Zoonoses, diseases that people catch from animals, are not limited to COVID-19. An international report released in 2012 shows that 56 of the most common zoonoses are responsible for 2,5 billion cases and 2,7 million deaths worldwide each year. The zoonoses include, inter alia, rabies, toxoplasmosis, Q fever, dengue fever, bird flu, Ebola virus and anthrax. According to the National Institutes of Health, almost 16 percent. of all deaths in the world can be attributed to infectious diseases, with zoonoses accounting for 60%. known infectious diseases and 75 percent. emerging infectious diseases.
It is also worth mentioning the diseases of the respiratory system acquired from animals that have wreaked havoc on humanity in the last century. The Spanish flu, according to various data, led to the death of 50 to 100 million people worldwide. Why are the diseases that people catch from animals are so dangerous for us?
Our immune system is not equipped to fight zoonotic viruses
One of the main reasons we suffer so much from zoonoses is because our immune system doesn’t know how to deal with them. Most viruses that enter the human body are either effectively destroyed by our immune system or are excreted without harming our body. Sometimes, however, an animal virus manages to enter human cells and begins to replicate.
During replication, the virus can mutate and adapt to the new human host. When this occurs, the human immune system must create an immune response. Unfortunately, since he has not dealt with this threat so far, he has no pre-existing immunity in his arsenal. So before it activates and adapts to the opponent, it may already mutate several times, e.g. in order to replicate faster or even to avoid a clash with cells of the immune system.
As Christopher Coleman, professor of Infection Immunology at the University of Nottingham in the UK, told Medical News Today, the general assumption is that viruses that evolve in the host are less dangerous to the host. They want to get transmission, but don’t care too much about killing the host quickly. This is not always successful, but usually viruses that adapt to the human body may be less dangerous in the long run as there is some kind of deadlock between the virus and the host.
The expert also points out that a virus that will fully adapt to an animal host can be completely harmless to humans. Coleman, who deals with research on highly pathogenic coronaviruses, also gave examples of coronaviruses that are highly lethal to animals and completely harmless to humans. They include, among others infectious bronchitis in chickens, infectious peritonitis in cats, infectious gastroenteritis in pigs.
“On the other hand, a virus that evolves in animals but also has the ability to infect humans may be more lethal once it begins to spread to humans,” added Coleman.
What do bats have that humans lack?
SARS and MERS, as well as Ebola, and there are many indications that SARS-CoV-2 also comes from bats. Interestingly, they are non-lethal to these mammals, making them ideal hosts for these virulent viruses.
Research conducted at the University of Berkeley in California, by Professor Cara Brook, partially provides an answer to the question of what bats have and what humans lack. Brook noticed that some bats develop an antiviral immune response called continual switching on the interferon pathway. In most other mammals, over-vigilance of the immune system causes harmful inflammation. The immune system of bats has developed properties that protect against inflammation.
What protects bats makes other mammals more vulnerable. Why? Because viruses have to somehow adapt to the immune response of bats. They have an “incentive” to continue mutating for faster replication. The immune system of bats causes viruses to eventually strengthen themselves – by “fighting” with a competitor, they become stronger.
Brook’s team noted that if our immune system responded to viruses in the same way as that of bats, there would be widespread inflammation in our body.
All this means that we do not have a chance at the beginning against new zoonotic viruses. It is important to know the original vector of the virus. Thanks to this, we can learn its structure and methods of combating. There are several theories about the origin of the SARS-CoV-2 coronavirus that we are sharing. Here they are:
- Coronavirus from China. People could get infected from snakes
- Discovery of Chinese scientists. Pangolins may be the host of the coronavirus
- Scientists are looking for the source of the coronavirus. What animal did man get infected?
- SARS-CoV-2 coronavirus is a chimera of two viruses? Scientists have a new theory
Have a question about the coronavirus? Send them to the following address: [email protected]. You will find a daily updated list of answers HERE: Coronavirus – frequently asked questions and answers
The content of the medTvoiLokony website is intended to improve, not replace, the contact between the Website User and their doctor. The website is intended for informational and educational purposes only. Before following the specialist knowledge, in particular medical advice, contained on our Website, you must consult a doctor. The Administrator does not bear any consequences resulting from the use of information contained on the Website.