Dominant global viral strain found in Beijing cases
By Leng Shumei Source:Global Times Published: 2020/6/22 21:56:23
The coronavirus mutation discovered to be currently dominating the world has been pinpointed as the cause of the latest COVID-19 outbreak in Beijing, which experts say indicates that the virus was imported from outside China.
The Chinese Center for Disease Control and Prevention (CDC) has released the viral genome sequence from the recent clusters of COVID-19 infections related to Beijing's Xinfadi wholesale market late Thursday, which came from both COVID-19 case samples and environmental samples.
The CDC has submitted the relevant genome sequence to the World Health Organization and the Global Initiative on Sharing All Influenza Data to share the data globally.
Data shows that the virus carries a point mutation in the Spike protein D614G.
According to previous research and media reports, the mutation Spike D614G began spreading in Europe in early February, and increased significantly to 26 percent of the total isolated sequences available in the GenBank. In May, this viral strain had become the most dominant strain spreading around the world, presenting itself in 70 per cent of sequenced samples in the Genbank.
According to a research paper released on the bioRxiv on June 14, the mutation can increase transduction of the virus across a broad range of human cell types, including cells from the lung, liver and colon.
The mutation is also more resistant to proteolytic cleavage during production of the protein in host cells, suggesting that replicated viruses produced in human cells may be more infectious due to a greater proportion of functional (uncleaved) Spike proteins per virion.
The mutation Spike D614G has been discovered in the virus spreading around Europe, Taiwan island and Colombia in South America. But it has not been discovered on the Chinese mainland so far, media reported citing a virologist.
Yang Zhanqiu, deputy director of the Pathogen Biology Department at Wuhan University, told the Global Times on Monday that the results potentially indicate that the virus causing the latest outbreak in Beijing was imported from outside China.
Yang said the fact that cases in Beijing rocketed from zero to more than two hundred in just more than one week indicate that the virus is more contagious than the strain that spread in Wuhan, which Yang deemed maybe a reason for why the epidemic outside China still cannot not be controlled while most parts of China have not witnessed new domestic cases for months.
From June 11-21, Beijing reported 236 COVID-19 cases, all of whom have been hospitalized. Another 22 asymptomatic cases are under medical observation, Beijing health authorities said.
According to the Hubei provincial health authority, COVID-19 cases in Wuhan reached 270 as of January 20, nearly one month after the first COVID-19 cases were reported in the city on December 27.
Concerns mounted if the more contagious strain would increase the difficulty for Beijing authorities to curb the outbreak.
Experts explained that with the path of the virus causing the clustered infections at Xinfadi Market being clear along with the infection source, the outbreak in Beijing can be quickly controlled.
Beijing discovered nine new cases on Sunday, the first time the city's new daily cases fell below single digits since June 12.
Some experts reached by the Global Times estimated that the outbreak could ease within the week due to Beijing's strict measures and city-wide screening.
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