How viruses evolve
What are viruses?
Viruses are the smallest of all the microbes. They are said to be so small that 500 million rhinoviruses (which cause the common cold) could fit on to the head of a pin. These are special because these are only alive and able to reproduce within the cells of other living beings. The cell they multiply in is called the host cell.
The virus is made up of a nucleus of genetic material, either DNA or RNA, surrounded by a protective coat called a capsid made up of protein. Sometimes the capsid is surrounded by an extra spikey coat called the envelope. Viruses are capable of lining up and getting inside host cells.
How can the virus stand out?
After a chance interaction with an animal host, a virus may first develop in humans, during which a person becomes infected. Viruses often spread only from animals to humans but cannot be transmitted from one person to another. However, in rare cases, the virus can survive transmission between humans. Doctors and other health care professionals first identify a new virus after testing and finding no match for known illnesses. If they cannot assign the virus from a particular virus through testing to known protein markers or genetic material, and there are increasing numbers of similar cases, this may point to something new, such as the recently identified SARS-CoV-2 virus.
The variation in viruses is a global issue. It has been established in the last decade that the most numerous biological entities on the planet are viruses. The oceans and soil host large numbers of virus-like particles (VLPs), often resembling tailed bacterial DNA viruses. Moreover, some of these environmental viruses are surprisingly large and complex, such as algae psycho dna viruses or amoeba mimivirus, a 1.2 Mb DNA virus capable of encoding almost 1000 genes. Viruses thus represent an extensive and diverse source of novel genes. However, this population’s evolutionary dynamics and their effect on the hosts are not well understood. This virus gene pool is also likely to affect host evolution since all prokaryotic genomes are known for prophage colonization. So this vast pool of viruses specifically interacts with prokaryotes and the ‘tree of life.’ The study of the evolution of viruses has become an extension of any evolution.
Both biological and demographic factors can facilitate viral spread. Biologically, if a given virus is capable of infecting the body through accessible entry points, such as epithelial cells in the nose, it can enter the respiratory tract and spread relatively easily. The virus can spread in the air and on surfaces while a person is coughing or sneezing.
Viral spread will also rely on how rapidly a virus will replicate itself, thereby dispersing into other parts of the body or into new hosts. Demographically, clustered populations in which people live close to each other are more likely to experience rapid spread of the virus than dispersed populations.
Viruses and immune systems
People’s immune systems have memories of past infections impacting how they are going to respond to a virus. It creates proteins called antibodies that recognize and neutralize possible threats, to avoid infection once the body is exposed to a virus. For example, people who contract flu probably built up some degree of immunity due to previous exposure, including the flu vaccine. In the case of a new coronavirus, this virus has not been seen by the immune system before and the adaptive response is slower.
To conclude simply
Viruses, like cell-based life, undergo evolution and natural selection and most of them evolve rapidly. When two viruses simultaneously infect a cell, they may swap genetic material to produce new, “mixed” viruses with unique properties. It can occur , for example, with flu strains. Viral evolution is a subfield of evolutionary biology and virology specially concerned with viral evolution.
White blood cells attack foreign organisms that invade and destroy the body.
This reaction is organized and coordinated by white blood cells called lymphocytes (or: Lymphocytes) CD4.
These lymphocytes are also the central target of HIV, which attacks these cells and penetrates into them. After successfully penetrating these cells, he enters his genetic material into it, and in this way he clones (duplicates) himself.
The new, cloned viruses begin to exit the host lymphocyte and enter the bloodstream, where they begin to search for new cells to attack them.
Meanwhile, the host lymphocyte and adjacent healthy CD4 cells die due to the effects of the attacking virus. This phenomenon is a cyclical phenomenon that repeats itself, again and again.
Thus, in this process, millions of new cells are produced from the virus daily. At the end of this process, the number of CD4 cells decreases, until a serious immune deficiency is reached, which means that the body is unable to fight viruses and germs that attack it, causing it to rot and diseases.