China said on Friday it had identified a European strain of coronavirus as having sparked the recent Beijing outbreak, while the World Health Organization said only that it had been imported from outside the city and needed further investigation.China has released genome sequencing data from samples taken in Beijing, which officials there said identified a European strain based on preliminary studies.
Some 183 people have been infected in the resurgence that began eight days ago linked to Beijing’s sprawling wholesale food centre of Xinfadi.
“Strains and viruses move around the world”, WHO’s top emergencies expert Mike Ryan told a Geneva news conference.
“So I think it’s not indicating that Europe is the origin of the disease at all. What it is saying most likely is the disease was most probably imported from outside Beijing at some point.”
It was critical to establish when the virus arrived in Beijing, how many people were infected along the way, and what factors amplified its spread, Ryan said. But it was “reassuring” that the virus appeared to be of human origin and had not jumped the species barrier again, he added.
China had come under pressure to make the data public sooner rather than later as COVID-19 cases mount in the capital.
The U.S. administration has blamed the Chinese government for moving too slowly to contain the initial outbreak.China says it wasted no time in releasing information including the genome sequence of the first outbreak in Wuhan.
The latest genome sequencing was published late on Thursday, and had also been shared with the WHO and the Global Influenza Data Initiative (GISAID), said the Chinese Center for Disease Control and Prevention (CDC).
Virus genome sequencing is a vital and rapidly-developing tool in the diagnosis of COVID-19 and in understanding the spread and control of the new coronavirus.
Details published on China’s National Microbiology Data Center website revealed the Beijing genome data was based on three samples – two human and one environmental – collected on June 11. That was the same day the Chinese capital reported its first new local COVID-19 infection in months.
“According to preliminary genomic and epidemiological study results, the virus is from Europe, but it is different from the virus currently spreading in Europe,” CDC official Zhang Yong was cited as saying in an article published on Friday by the Central Commission for Discipline Inspection on its website.
“It’s older than the virus currently spreading in Europe.”
Wu Zunyou, the CDC’s chief epidemiology expert, had told state media this week the Beijing strain was similar to Europe’s, although not necessarily directly transmitted from European countries. Wu did not elaborate on those comments made before the genome data release.
The strains found in the United States and Russia were mostly from Europe, he added.
The first cluster of coronavirus infections was traced to the Huanan seafood market in Wuhan in December. It has since infected almost 8.5 million people globally.
On the origins of the strain that hit Beijing, Wu said it did not originate from the Chinese capital.
“It must be some people or goods outside of the city that carried it into the (Xinfadi) market,” Wu said in a state television interview aired on Friday.
“It’s unclear who, or what kind of goods, had brought the virus into Beijing.”