Virus evolution: Mutant career
Introduction
Viruses and their influence are unfortunately more present in our society than ever. Viral load, percentages, infected and reinfections are terms that many had never thought about until this pandemic. Even so, there are even more complex mechanisms that underlie current events: viral evolution is an exciting process, and in this article we want to show it.
Developing
They enter the cell, take over their mechanism for replication of genetic information, replicate themselves, and copies leave the cell to continue infecting.
Due to this speed and genetic plasticity, many viruses, especially those of RNA, have exceptionally high mutation rates. This mutation rate combined with the natural selection process allows viruses to adapt quickly and effectively to host defense mechanisms. This is essential to understand the pandemic that we are living, then, what is the coronavirus but an adaptation of a virus already present in animals?
Change ensures success
Let’s start with an already known subject: the flu. Virus influenza and influenza B are equally prevalent in humans. Even so, the first presents an evolution rate the triple quickly than the second. For what is this?
A study published in the Journal of Virology tries to give us the answer:
Apart from the reaction of the immune system itself (positive and negative selections, complex terms that we will not cover here) Molecular level mutations can play an important role in the adaptation of the virus.
It may sound obvious, but it is not so simple directly that a higher evolution rate is due to a greater number of mutations. Many mutations can be deleterous or inappropriate for the virus. What if due to the mutation kills the host faster? The virus would run out of sustained propagation. It is a very complex change game, in which the most effective changes can end by selection.
If a mutant virus keeps the host more time being able to reproduce more and infect more people, this is the one that will reach most people. We have to have clear one: viruses do not mutate to be better. The changes are randomly, and the most valid end up extending. Following the example of the Coronavirus Covid-19, how many mutant strains will have failed until the capable of infecting humans came?
Types of mutation
We can differentiate two types of general viral mutations:
Antigenic change is a process by which two or more viruses (of the same or different strains) are intermingled to give rise to a new one. Keeping simple things, everything could be summed up in this greatly misleading the immune system. You can know and fight them separately, but their union is something that has never faced each other and therefore requires developing new mechanisms. A clear example of this is the famous flu.
Antigenic drift is a mutation in virus surface proteins that are those that the immune system normally recognizes and attacks. It does not require interaction with other viruses: these occur spontaneously. The modification of the same hinders the defense to the immune system through the antibodies of previous infections. Have you never wondered why the flu vaccine is annual?
Our body needs to learn to combat diseases, and vaccines are the most effective means. If a virus changes, the vaccine will have to do it with it to teach our body to fight it without the need for infection.
Mutation and coronavirus
How to apply all this knowledge to the current reality?
Really, knowing the mutation rate of COVID-19 in such a short period of time is impossible. The existence of two different strains has been speculated, but due to the low sample groups (only 103 analyzed samples), statistical biases and various opinions, this idea seems to have been diluted over time.
conclusion
As experts in the field ensure in this extract of the Journal of Microbiology, mutation rates during a pandemic should not worry. Many mutations are even negative for viruses, and for substantial changes in severity or transmission, several genes have to vary together. It is very unusual for a virus to mute so much to vary the dynamics that we are beginning to know in such a short time.
Again, the call is to calm. Variations in the natural world are extremely common, and the current objective is to stop the pandemic to avoid its expansion.
Leave feedback