Dubai, United Arab Emirates (CNN) — The source of the next coronavirus mutant must be known so that it can be confronted. For the Omicron mutant, the answer to the question of how a completely different mutant suddenly appeared from the one that preceded it remains a puzzle.
“When the virus strain first started circulating, it was hard for me to comprehend the extent of its spread,” said Mehul Suthar, a virologist at Emory University.
Then came BA.2, the rapidly spreading ‘omicron’ mutant, now prevalent in the United States.
Viruses change all the time, often in ways that compromise their chances of survival, but these mutations can, from time to time, work in the virus’s favour.
The virus is still alive… rare
The virus that you excrete by sneezing or coughing may differ slightly from the virus you contracted, and the reason for this is that viruses mutate, especially when their genetic code consists of RNA, which is similar to the structure of our DNA.
Dr. Mike Ryan, Executive Director of the World Health Organization’s Health Emergencies Program, explained during a press conference held last March that: “During the virus’s reproduction process, errors occur during the reproduction of its code, and these errors often result in an incompetent virus. or dead.”
Rarely, however, do these incidents give the virus an advantage, making it more widespread, or perhaps better by evading our acquired immunity.
In an op-ed published in the New York Times this week, Sarah Kobe, an assistant professor of ecology and evolution at the University of Chicago, explained that the transmissibility of the Corona virus will eventually reach its maximum.
However, it is possible that the virus will not stop evolving in ways that evade our immune response.
“Before Omicron came out, I think most people in the field said we’d see immune escape by accumulating these mutations one by one,” Kobe told CNN.
Over time, and hundreds of infections recorded, circulating viruses are drifting further and further away from their predecessors on the evolutionary tree, a process known as antigenic drift.
It is unlikely that “slow change” would lead to the emergence of Omicron, said Maritigi Venter, a professor in the Department of Medical Virology at the University of Pretoria, South Africa.
This means that the virus evolved gradually in a community where it was not monitored, and she noted that South Africa, where many of the early Omicron samples have been identified, has a good surveillance programme.
Thus, it was difficult for a Mutant like Omicron to slowly sneak in, instead, his appearance seemed strangely abrupt.
“The delta mutate almost disappeared, and suddenly we saw an omicron that was completely different,” Venter added.
change track
In some cases, viruses mutate, and the “antigenic shift” is a more dramatic change that can occur, for example, when viruses in animals find their way to humans, or when two strains infect the same person and exchange genes, similar to rare cases that led to the emergence of a virus A hybrid containing stretches of the delta and omicron mutant genes.
Helix researchers, whose tests helped track a number of the mutant, identified a small number of people with the delta-omicron mutation combined in the United States, among regarding 30,000 samples of the Corona virus, between late November and mid-February, while Which was spread by both mutants.
Among those samples, the researchers identified 20 cases in which people were infected with both mutants at the same time, and one of these samples showed some evidence that the two mutants had exchanged genes, albeit at low levels. In addition, the researchers found two unrelated cases, due to their infection with hybrid viruses.
“There is currently no evidence that the two identified delta-omicron viruses are more transmissible compared to the widespread omicron mutants,” the researchers wrote.
“We don’t call it Delta Crohn’s,” Maria Van Kerkhove, a technical expert on COVID-19 at the World Health Organization, said in a statement last March.
At the time, Van Kerkhove said the mixture appeared to be spreading “at very low levels”, but cautioned that more testing was needed to get a clearer picture of whether or not it was spreading.
However, the ability to exchange genes has led to the re-emergence of multiple viruses, primarily influenza.
The genetic material of influenza is made up of multiple pieces of RNA, which can move around when two viruses infect the same cell. This is known as virus remodeling.
Kobe explained that the Corona virus “can actually do something that is difficult to understand,” referring to the process of gene exchange called genetic recombination.
Omicron puzzle
There doesn’t seem to be a single explanation that fits Omicron’s background precisely, but experts are researching several theories that might explain his sudden appearance last year.
The most common opinion seems to involve a prolonged infection in an immunocompromised person.
Venter said that these people do develop antibodies, but do not get rid of the virus.
This gives the virus ample time to accumulate changes, potentially enabling it to evade an infected person’s antibodies and develop immune resistance.
Venter added that there is another theory known as reverse zoonosis, in which the virus is transmitted from humans to a group of animals, where it accumulates new mutations before returning back to humans.
“Most of the pathogens that frequently infect us are able to do this because they evade our partial immunity to previous infectious strains,” Kobe said.
