Chinese researchers involved in identifying the pathogen that causes
COVID-19 as the disease first began its rapid spread said they stress
both speed and prudence in their work in order to provide quick and
accurate information to aid the global fight against the virus. After COVID-19 hit Wuhan, Hubei province, in late December 2019, they
managed to isolate the virus on Jan 7, 2020 after about a week's work,
breaking the record for the shortest time to get a grip on an emerging
contagious illness, said Wu Zunyou, chief epidemiologist at the Chinese
Center for Disease Control and Prevention. Two days later, China shared its initial progress in determining the
pathogen that caused the viral outbreak with the World Health
Organization. Then on Jan 12, Chinese researchers from three
institutions uploaded genome sequences of five viral strains to
GISAID-the global initiative on sharing all influenza data-an
international genomic database. "Lack of understanding about the pathogen is analogous to missing
enemies on the battlefield," said Wu Guizhen, the chief expert on
biosafety at the China CDC. She added that swift identification of the
pathogen won precious time for global scientists to develop testing kits
and vaccines, screen for effective treatment and trace the origin of
the virus. Zhou Peng, a researcher at the Chinese Academy of Sciences' Wuhan
Institute of Virology, said technological advances have markedly
shortened how long it takes scientists to sequence the genome of a viral
sample. By comparison, the full genome sequence of the virus that caused the
severe acute respiratory syndrome outbreak in 2003 was released by
Canadian scientists six months after the first case was detected. "Currently, a genome sequence can be obtained within 24 hours at the
fastest. But when faced with an emerging new virus, it will certainly
take longer to verify results and analyze which pathogen causes the
disease," he said. Among the first group of novel coronavirus genome sequences released
publicly, three were mapped out by the emergency technical center under
the China CDC's National Institute for Viral Disease Control and
Prevention in Beijing. Tan Wenjie, head of the center, said it took less than two days for
laboratory workers to obtain the genetic makeup of the four viral
samples from Wuhan that arrived on Jan 2. To ensure the accuracy of the results, Tan said three generations of
genome sequencing techniques were deployed to verify the results, and
multiple units at the China CDC, including its P3-level biosafety
laboratory and the China National Influenza Center, were mobilized to
expedite the procedure. The fast-paced search for the pathogen also played out at the Chinese
Academy of Medical Sciences' Institute of Pathogen Biology in Beijing,
which contributed to sharing one genome sequence on Jan 12. Ren Lili, a researcher at the institute, said the first hurdle in
putting together a complete genome sequence was the low viral load in
the samples available. "Compared with the huge quantities of human genome and microbiome in
viral samples, the virus genome only takes up a very small proportion,"
she said. "It is thus challenging to minimize effects from other genomes
when handling clinical samples." A microbiome is a collection of the
genetic material of all microbes in a human body. In addition to laying out the genome sequence of the virus, Ren said
it is crucial to parsing the genomic information to extrapolate whether
it is a new or known pathogen that causes the patient to get sick, which
requires extensive knowledge and a profound understanding of virology. "Within 50 hours of receiving the sample, we had sequenced the virus'
genome, verified our findings and compared it with known coronaviruses
to point out differences," she said. The National Health Commission said it had commissioned a handful of
high-level laboratories in the country to isolate the virus and identify
genome sequences independently and simultaneously. Wu Zunyou, from the China CDC, said during a previous interview that
the top health authority was not assured until results from all
laboratories had unanimously suggested that a novel coronavirus was the
pathogen. "High-level experts were also convened together again to
verify the results and confirm the conclusion," he added. "In terms of sequencing the virus," Ren said, "speed is not the sole
purpose. It is equally important, if not more so, to ensure that the
information and data that we produce is of high quality."
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