Search For SARS-CoV-2 Origin Continues
The first human cases of COVID-19 disease were initially reported by local officials in Wuhan City, China, in December 2019, said the World Health Organization (WHO).
While some of the earliest known human cases had a link to a wholesale food market in Wuhan, others did not, said the WHO in Situation Report #94, published on April 23, 2020.
Environmental samples taken from this market in December 2019 tested positive for the SARS-CoV-2 coronavirus, further suggesting that the market in Wuhan City was the source of this outbreak.
Or played a role in the initial amplification of the outbreak.
The full genetic sequence of SARS-CoV-2 from the early human cases in China and the sequences of other viruses isolated from all over the world show that SARS-CoV-2 has an ecological origin in bat populations.
The available evidence to date suggests that this coronavirus has a natural animal, zoonotic source, and is not a manipulated or constructed virus, says the WHO.
Since there is usually limited close contact between humans and bats, it is more likely that transmission of the virus to humans happened through another animal species, one that is more likely to be handled by humans.
Many researchers have been able to look at the genomic features of SARS-CoV-2 and have found that evidence does not support the claim that SARS-CoV-2 is a laboratory construct.
If it were a constructed virus, its genomic sequence would show a mix of known elements.
However, the WHO says ‘this is not the case.’
Another coronavirus, SARS-CoV-1, the cause of the Severe Acute Respiratory Syndrome (SARS) outbreak in 2003, was also closely related to other coronaviruses isolated from bats.
These close genetic relations of SARS-CoV-1, SARS-CoV-2, and other coronaviruses suggest that they all have their ecological origin in bat populations.
Many of these coronaviruses can also infect several animal species.
For example, SARS-CoV-1 infected civet cats and then humans, while the virus causing the Middle East Respiratory Syndrome (MERS-CoV) is found in dromedary camels, and has continued to infect humans since 2012.
All the published genetic sequences of SARS-CoV-2 isolated from human cases are very similar.
This suggests that the start of the outbreak resulted from a single point introduction in the human population.
According to the WHO, a number of investigations to better understand the source of the outbreak in China are currently underway, or planned, including investigations of human cases with symptom onset in late 2019.
Results from these studies are essential to preventing further zoonotic introductions of coronaviruses into the human population.
The WHO continues to collaborate with animal and human health experts, Member States, and other partners to identify research priorities for the control of COVID-19, including the eventual identification of the source of the virus in China.
SARS-CoV-2 pandemic news published by Precision Vaccinations.