Written By: Longjam Dineshwori | Updated : November 8, 2020 1:07 PM IST
Preliminary findings of studies indicate that this mink-associated variant has moderately decreased sensitivity to neutralizing antibodies.
Denmark has ordered the slaughter of all the estimated 15-17 million minks in the country after discovering new coronavirus cases linked to mink farms. The country's health authorities have warned that a mutation of the virus had jumped from minks to humans and infected 12 people.
According to the Danish health authorities, the new strain, known as "Cluster 5", is not inhibited by antibodies to the same degree as the normal virus. This they fear could threaten the efficacy of vaccines that are being developed across the globe.
Since June 2020, as many as 214 human cases of COVID-19 have been identified in Denmark with SARS-CoV-2 variants associated with farmed minks, including 12 cases with a unique variant.
The World Health Organization (WHO) also warned that this new variant had a combination of mutations, or changes that have not been previously observed. In addition, the implications of the identified changes in this variant are not yet well understood, the UN health agency added.
The WHO also cited preliminary findings of studies that indicated this mink-associated variant has "moderately decreased sensitivity to neutralizing antibodies." It called for further studies to verify the preliminary findings and "to understand any potential implications of this finding in terms of diagnostics, therapeutics and vaccines in development".
Besides Denmark, five other countries have discovered SARS-CoV-2 in minks, according to WHO. These include the United States, Italy, the Netherlands, Spain and Sweden.
Following these reports, Britain has banned entry to all non-resident foreigners coming from Denmark.
Although coronavirus is believed to be ancestrally linked to bats, the origin and intermediate host(s) of SARS-CoV-2 (the novel coronavirus responsible of the ongoing pandemic) have not yet been identified, according to WHO. Below are some of the theories of SARS-CoV-2 origins:
A paper published in July 2020, concluded that SARS-CoV-2 came from a virus with relatively generalist properties circulating in horseshoe bats for several decades.
The generalist property of the virus means an intermediate host is not required for any evolutionary change, explained the authors from the Glasgow Centre for Virus Research, Scotland, UK, suggesting direct bat human transmission.
However, the fact that SARS-CoV-2 was first detected in Wuhan, China, where the horseshoe bat is not found, hints at the presence of an intermediary host.
As the virus has been around for decades it may have emerged in another host, which only facilitated transmission, the researchers noted.
Some experts have theorized that pangolins could be the missing intermediate species that facilitate transmission to humans.
Pangolins, sometimes called scaly anteaters, are believed to be the most trafficked mammal in the world. Its protective scales are in high demand in Asia for use in traditional Chinese medicine while its meat is considered a delicacy in some countries.
This is one theory that has been dismissed by scientists worldwide, including David Robertson, head of bioinformatics at the Medical Research Council University of Glasgow Centre for Virus Research, Scotland, UK.
During the earliest days of the pandemic, speculations started doing the rounds that the new virus had been deliberately released from the Wuhan Institute of Virology.
Refuting this theory, Robertson argued that if the virus had been human made, that would show in its genome.
"SARS-CoV-2 is like nothing we have seen before. It really is highly unlikely that someone created it; it is not put together from pieces we know about," added Robertson, who is also the co-author of the paper published in the Lancet.
However, the exact origin of the novel coronavirus still remains a mystery.
