Monday, March 23, 2020

China's Bat Woman

Really interesting article:BEIJING—The mysterious patient samples arrived at Wuhan Institute of Virology at 7 P.M. on December 30, 2019. Moments later, Shi Zhengli’s cell phone rang. It was her boss, the institute’s director. The Wuhan Center for Disease Control and Prevention had detected a novel coronavirus in two hospital patients with atypical pneumonia, and it wanted Shi’s renowned laboratory to investigate. If the finding was confirmed, the new pathogen could pose a serious public health threat—because it belonged to the same family of bat-borne viruses as the one that caused severe acute respiratory syndrome (SARS), a disease that plagued 8,100 people and killed nearly 800 of them between 2002 and 2003. “Drop whatever you are doing and deal with it now,” she recalls the director saying.

Shi—a virologist who is often called China’s “bat woman” by her colleagues because of her virus-hunting expeditions in bat caves over the past 16 years—walked out of the conference she was attending in Shanghai and hopped on the next train back to Wuhan. “I wondered if [the municipal health authority] got it wrong,” she says. “I had never expected this kind of thing to happen in Wuhan, in central China.” Her studies had shown that the southern, subtropical areas of Guangdong, Guangxi and Yunnan have the greatest risk of coronaviruses jumping to humans from animals—particularly bats, a known reservoir for many viruses. If coronaviruses were the culprit, she remembers thinking, “could they have come from our lab?”

...In many bat dwellings Shi has sampled, including Shitou Cave, “constant mixing of different viruses creates a great opportunity for dangerous new pathogens to emerge,” says Ralph Baric, a virologist at the University of North Carolina at Chapel Hill. And in the vicinity of such viral melting pots, Shi says, “you don’t need to be a wildlife trader to be infected.”

...On the train back to Wuhan on December 30 last year, Shi and her colleagues discussed ways to immediately start testing the patient samples. In the following weeks—the most intense and the most stressful time of her life—China’s bat woman felt she was fighting a battle in her worst nightmare, even though it was one she had been preparing for over the past 16 years. Using a technique called polymerase chain reaction, which can detect a virus by amplifying its genetic material, the first round of tests showed that samples from five of seven patients contained genetic sequences known to be present in all coronaviruses.

...By January 7 the Wuhan team determined that the new virus had indeed caused the disease those patients suffered—a conclusion based on results from polymerase chain reaction analysis, full genome sequencing, antibody tests of blood samples and the virus’s ability to infect human lung cells in a petri dish. The genomic sequence of the virus—now officially called SARS-CoV-2 because it is related to the SARS pathogen—was 96 percent identical to that of a coronavirus the researchers had identified in horseshoe bats in Yunnan, they reported in a paper published last month in Nature. “It’s crystal clear that bats, once again, are the natural reservoir,” says Daszak, who was not involved in the study.
In 2004, an international team of scientists takes blood and swab samples from bats at night in order to discover potential bat-borne pathogens.

...Many scientists say the world should move beyond merely responding to deadly pathogens when they arise. “The best way forward is prevention,” Daszak says. Because 70 percent of animal-borne emerging infectious diseases come from wild creatures, “where we should start is to find all those viruses in wildlife globally and develop better diagnostic tests,” he adds. Doing so would essentially mean rolling out what researchers such as Daszak and Shi have been doing on a much bigger scale.

Such efforts should focus on high-risk viral groups in certain mammals prone to coronavirus infections, such as bats, rodents, badgers, civets, pangolins, and nonhuman primates, Daszak says. He adds that developing countries in the tropics, where wildlife diversity is greatest, should be the front line of this battle against viruses.

...Back in Wuhan, China’s bat woman has decided to retire from the front line of virus-hunting expeditions. “But the mission must go on,” says Shi, who will continue to lead research programs. “What we have uncovered is just the tip of an iceberg.” Daszak’s team has estimated that there are as many as 5,000 coronavirus strains waiting to be discovered in bats globally. Shi is planning a national project to systematically sample viruses in bat caves—with much greater scope and intensity than her team’s previous attempts.

“Bat-borne coronaviruses will cause more outbreaks,” she says with a tone of brooding certainty. “We must find them before they find us.”

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