Before March 2020, many people believed pandemics were a thing of the past. COVID-19 was the evaluation step. The virus that caused it, SARS-CoV-2, is still unknown to scientists, but it spread swiftly to nearly every country on the planet. Over the last two years, the virus has grown into many new types. In this Special Feature, we explore the CoV-2s that have arisen in reaction to SARS and ask what lessons scientists have gained.
In late 2019, the number of pneumonia patients in central China surged drastically. By January 7, scientists had discovered and isolated a previously unknown coronavirus, now known as SARS-CoV-2.
On March 11, 2020, the WHO classified COVID-19 as a pandemic.
Officials have detected around 458 million occurrences of COVID-19, the sickness caused by SARS-CoV-2, after two years. The sickness has robbed the lives of more than 6 million persons.
The First Cases:
On December 29, 2019, the Huanan Seafood Wholesale Market in Wuhan, central China, was tied to four occurrences of pneumonia with an unexplained etiology.
The causative agent, SARS-CoV-2, was found on January 7, 2020, and its genome was sequenced on January 10, 2020.
On January 2, 2020, doctors found 41 patients infected with SARS-CoV-2 at a Wuhan hospital. At one point or another, 27 of them have worked in the fishing sector.
Other human coronaviruses include:
Coronaviruses infect both animals and humans in varied ways. The majority of them cause infections in the upper respiratory tract, which result in moderate to severe symptoms including colds.
In recent years, two coronaviruses, SARS-CoV and MERS-CoV, have caused increasingly severe sickness. The Asian pandemic of the severe acute respiratory syndrome (SARS) was caused by SARS-CoV, which was identified by scientists in November 2002. (SARS). According to the Centers for Disease Control and Prevention (CDC), 774 persons who had been diagnosed with SARS died.
The sickness caused by MERS-CoV-2, Middle East Respiratory Syndrome (MERS), was originally diagnosed in Saudi Arabia in 2012. MERS has a substantial death rate, with three to four infected individuals dying for every 10 infected. This nausea still arises on a random basis every now and then.
Both of these coronaviruses created epidemics with substantial death rates, but their transmission could be prevented before they became pandemic. Was it acceptable to say that we were ready for the next coronavirus?
The origins of SARS-CoV-2:
SARS is assumed to have started in bats, but MERS was carried to humans via camels. When it comes to SARS-CoV-2, however, researchers haven't reached an agreement on any of the various ideas that have been suggested.
SARS-CoV-2 was assumed to have originated in bats at first. Because the spike protein on SARS-CoV-2 is so unique from those of coronaviruses identified in bats, researchers ruled out that possibility.
Researchers think assume the virus originated in bats but had a host between bats and humans. According to a new study that has not yet been peer-reviewed, live pigs for sale at the Huanan Seafood Wholesale Market in Wuhan, the hub of early cases, could have been the intermediate host.
"SARS-CoV-2 development likely evolved from several zoonotic occurrences," according to a new study on the evolution of SARS-CoV-2, which has yet to be peer-evaluated. The researchers make no mention of the animal hosts in between.
Or, as numerous news sites suggested, did SARS-CoV-2 escape from a Wuhan lab? The WHO has categorized this hypothesis as "extremely implausible."
"One misstep was pointing fingers at China and condemning them for the virus's genesis," he adds. As a result, I believe the Chinese have reacted adversely."
"I fully believe in natural origins [of SARS-CoV-2], but the Chinese may have made things a lot easier if they had released their data sooner,".
What causes variants to appear?
The first Wuhan strain of SARS-CoV-2 moved throughout the world for roughly a year.
A new mutation, which was 50 percent more transmissible than the original and had 17 separate modifications, was determined to be to respond, according to researchers. The WHO recognized it as B.1.1.7, or the Alpha version, in December 2020.
The following are the variants of concern and the site where they were discovered:
Alpha (B.1.1.7): The U.K., September 2020
Beta (B.1.351): South Africa, October 2020
Gamma (P.1): Brazil, December 2020
Delta (B.1.617.2): India, October 2020
Omicron (B.1.1.529): Multiple countries, November 2021
Each species is distinguished by its particular set of features. Some kinds are more infectious than others, while others are more toxic. COVID-19 waves have been created in large quantities as a result of these properties.
What components have a function in variations?
Viruses are continually changing. When they reproduce, which occurs regularly, their genetic material is duplicated. When a component of the genetic material is duplicated improperly, a mutation arises.
The genetic material of a coronavirus is ribonucleic acid (RNA). RNA polymerase, an enzyme that routinely makes mistakes, is in charge of replication. The overwhelming majority of mutations result in a virus that cannot replicate or spread among individuals. On the flip side, certain modifications result in a virus that can replicate: a variation.
A viral mutation could afford it a competitive advantage, such as enhanced transmissibility or virulence, for example. If a variation is more transmissible, it has a higher probability of spreading swiftly and outcompeting earlier varieties. The coronavirus strains Alpha, Delta, and Omicron had the same behavior.
Is the epidemic finally coming to an end?
After two years of limitations, many have gotten ill with them, believing that the plague should be gone by now.
"One of my fears is that if we cease testing and sequencing so meticulously, we'll lose our ability to monitor these processes." "As we test less and sequence less, we'll lose our capacity to recognize new changes in real-time," scientists noted.