Written By: Longjam Dineshwori | Updated : February 10, 2021 8:18 PM IST
Researchers point the origin of Covid-19 to a "natural reservoir" in bats.
The novel coronavirus, which causes Covid-19, was first detected in China's Wuhan city in 2019. Since then several theories have surfaced regarding the origin of the virus. One is that the virus was 'intentionally' released from a laboratory in China. However, the World Health Organization (WHO) expert team who is investigating the origin of SARS-CoV-2 in Wuhan has dismissed this theory. The experts believe that the virus "most likely" crossed over to humans from an intermediary species. Peter Ben Embarek, WHO scientist for food safety and zoonosis, and team leader of the mission, told a press conference on Tuesday that work to identify the origins of Covid-19 points to a "natural reservoir" in bats, but it was unlikely that this happened in Wuhan.
Meanwhile, a study report published in Nature Communications has indicated that coronaviruses related to Sars-CoV-2, which is responsible for the ongoing pandemic, may be circulating in bats across many parts of Asia, including Japan, China and Thailand.
The study led by Lin-Fa Wang of the University of Singapore discovered a close relative of Sars-CoV-2 in horseshoe bats kept at a wildlife sanctuary in eastern Thailand. The isolated virus, named RacCS203, and SARS-CoV-2 exhibit 91.5 per cent similarity in their genomes, the researchers wrote in their report.
RacCS203 is also closely related to another coronavirus - called RmYN02 that is found in bats in Yunnan, China, and which shows 93.6% similarity to the genome of the Covid-19 virus.
Additionally, the researchers observed that antibodies in the bats and in a trafficked pangolin in southern Thailand were able to neutralise the pandemic virus. This further strengthens the evidence that SARS-CoV-2-related coronaviruses are circulating in Southeast Asia.
While the WHO investigators believe that the novel coronavirus mostly likely originated in animals before spreading to humans, they are not sure yet as to how this happened.
Embarek, who revealed the findings of their one-month long visit to Wuhan during a press conference on Tuesday, said that more work is needed to identify the source of the virus.
The WHO expert team includes experts from 10 countries. They arrived in China on January 14 to investigate the origin of SARS-CoV-2 and visited the Huanan Seafood Market, where Covid-19 cases first emerged in late 2019.
The experts didn't find any indication that the novel coronavirus was circulating in Wuhan even before the first official cases were recorded there in December 2019.
Liang Wannian, an expert with China's Health Commission, told BBC that Covid-19 could have been present in other regions before it was detected in Wuhan.
The WHO team also suggests the possibility of "cold chain" transmission through the trade of frozen food products. And therefore, the focus needs to shift to those supply chains to the Huanan Seafood Market, Dr Peter Daszak, a member of the WHO team, told BBC.
There are three reasons why need to understand the origin of the Covid-19 virus, according to Embarek.
The international investigative team includes epidemiologists, animal and human disease experts, veterinarians, medical doctors, virologists, as well as five WHO experts from the Food and Agriculture Organization and two representatives from the World Organisation for Animal Health (OIE).
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