Pangolins carry a 99% identical coronavirus, report Chinese scientists
GUANGZHOU, China––Will the Wuhan coronavirus, newly linked to pangolins, save one of the world’s most endangered animals?
Headlines over the weekend of February 8-9, 2020 amplified global panic that the number of confirmed Wuhan coronavirus deaths had soared beyond the 2003 toll from severe acute respiratory syndrome [SARS], and within another day topped 1,000.
But word came almost simultaneously from the South China Agricultural University in Guangzhou, capital city of Guangdong province, that researchers Shen Yongyi and Xiao Lihua may have positively identified the source of the mysterious coronavirus, known to have been circulating since November 2019 and of increasing concern to health authorities worldwide since mid-January 2020.
“Genetic sequences of viruses”
Revealing their findings at a February 7, 2020 media conference, Shen Yongyi and Xiao Lihua discovered “genetic sequences of viruses isolated from the scaly animals [pangolins] are 99% similar to that of the circulating virus,” reported David Cyranoski for the journal Nature.
“The work is yet to be formally published,” warned Cyranoski, but that development is imminently expected.
“The identity of the animal source of the coronavirus, named nCoV-2019,” Cyranoski explained, has been one of the key questions that researchers have been racing to answer. Coronaviruses are known to circulate in mammals and birds, and scientists have already suggested that nCoV-2019,” like SARS, “originally came from bats, a proposal based on the similarity of its genetic sequence to those of other known coronaviruses.
How did the coronavirus get from bats to humans?
“But the virus was probably transmitted to humans by another animal,” Cyranoski added. “Shen Yongyi and Xiao Lihua have identified the pangolin as the potential source of nCoV-2019 on the basis of a genetic comparison of coronaviruses taken from the animals and from humans infected in the outbreak and other findings.
“Previously, researchers have noted that coronaviruses are a possible cause of death in pangolins,” Cyranoski reported, “and that nCoV-2019 and coronaviruses from pangolins use receptors with similar molecular structures to infect cells.”
University of Sydney evolutionary virologist Edward Holmes and University of Glasgow computational virologist David Robertson told Cyranoski that they believe Shen Yongyi and Xiao Lihua are on the right track.
“Illegal trafficking is widespread”
As Cyranoski mentioned, “Pangolins are protected animals, but illegal trafficking is widespread,” despite penalties of 10 years or more in prison for convicted offenders.
Pangolins are eaten as a delicacy, while pangolin scales are used in traditional remedies for skin diseases, menstrual disorders, and arthritis.
The apparent link between pangolin consumption and the Wuhan coronavirus was reported in Nature only hours before Program for Monitoring Emerging Diseases [ProMED] network rapporteur Kunihiko Iizuka and the Johns Hopkins Center for Systems Science and Engineering on February 11, 2020 updated the coronavirus toll on humans to 42,310 medically confirmed cases worldwide, including 908 deaths, which became 1,016 deaths by the end of the day.
As of February 10, 2020, 96% of the identified cases had come in Hubei province, China, where 871 deaths had occurred.
Fewer than 1% of the identified cases, and far less than 1% of the deaths, had occurred outside of mainland China.
2% known mortality
Though relatively few Wuhan coronavirus cases have been confirmed outside of Hubei province, the length of time the coronavirus spread unnoticed even in the city of Wuhan itself indicates that it rapidly evolved to begin spreading from person to person in a mild enough form that the symptoms were mistaken for a common cold or flu.
By the time the Wuhan coronavirus was recognized as a new disease, most of the 11 million human residents of the city might already have been exposed. Hundreds of thousands of visitors and Wuhan residents with business elsewhere had already had the opportunity, at least, to spread the Wuhan coronavirus worldwide.
Among identified Wuhan coronavirus cases, ProMED reported, the known mortality rate is just 2%; outside of Hubei, it may be as low as two tenths of 1%.
This would make the Wuhan coronavirus much less deadly to most humans than ordinary seasonal influenzas. Most reported fatalities from the Wuhan coronavirus have come among senior citizens and other people with weakened immune systems.
SARS had 10% death rate
The 2003 SARS outbreak, by contrast, included only about 8,000 identified human cases worldwide, including 774 known fatalities, for a death rate approaching 10%.
Comparisons between the 2003 SARS outbreak and the Wuhan coronavirus outbreak are, however, inescapable. As is suspected of the Wuhan coronavirus, SARS occurred first among bats, spreading to civets through the live markets of southern China before crossing over into humans through wildlife consumers.
The Wuhan Municipal Market Supervision & Administration Bureau was already concerned about the expanding traffic in suspected illegally sold wildlife at the Huanan Seafood Wholesale Market as of September 25, 2019, according to Xinhua News, the official Chinese government news service.
Market was already suspect
The marketplace reportedly opened circa 2005, about two years after the SARS outbreak, apparently after public officials let their guard down against a recurrence.
On September 25, 2019, Xinhua News reported, two months before the first Wuhan coronavirus cases are believed to have occurred in humans, agents from the city departments of health, forestry, and police “cooperated to launch a special wildlife market rectification operation,” including “carpet inspections of merchants selling tiger frogs, snakes, hedgehogs, and other animals, examining their licenses to sell wild animals one by one.”
After the Wuhan coronavirus outbreak was recognized, with 41 of the first known cases linked in some manner to the Huanan Seafood Wholesale Market, the market was closed and sterilized. The Chinese central government later, on January 26, 2020, banned any and all commerce in wildlife for human consumption.
Pangolins, however, “were not listed on an inventory of items sold at the market — although the illegality of trading pangolins could explain this omission,” reported Cyranoski for Nature, noting that “Last month, scientists in Beijing claimed that snakes were the source of nCoV-2019, but that theory was dismissed by other researchers.”
Finished Cyranoski, “Arinjay Banerjee, a coronavirus researcher at McMaster University in Hamilton, Canada, says that a crucial detail is where in pangolins the researchers found the virus — for example, whether it was isolated from blood samples or rectal swabs. This will help to determine how it might have been passed to humans and how such transmission could be prevented in the future.”
Asked ProMED animal disease and zoonoses moderator Arnon Shimshony, “Which (domestic/wildlife) animal species are known to have been present in the market?,” at the time the Wuhan coronavirus was identified.
“What was the fate of the animals above? In case killed, details on the mode of disposal and quantitative data are requested. Was sampling of (any of) the market’s animals, in vivo/in vitro, performed?
“In case sampled, which lab tests have been applied? Results, per species, negative included, are requested.
“Were the state and local veterinary services involved throughout the procedures?”
All pangolins are on IUCN “Red List”
Pangolins, the suspected Wuhan coronavirus intermediary species between bats and humans, resemble tree-climbing cousins of the armadillos of the U.S. South, Southwest, and Central and South America, and also resemble South American ant-eaters. All are insectivores.
Yet, despite behavioral and physiological similarities, pangolins appear to be an example of parallel evolution, not actual relatives to either armadillos or ant-eaters.
All eight pangolin species––four indigenous to Asia, four to Africa––were in 2014 added to the International Union for Conservation of Nature “Red List,” meaning “at risk of extinction.”
The Convention on International Trade in Endangered Species (CITES) in 2017 banned international trade in pangolins.
Gaps in Chinese law
The Chinese government has yet to reinforce the CITES ban with new national legislation, but a ban on commerce in pangolin products was among 24 proposals submitted in March 2019 to the 13th National People’s Congress by the Democratic Alliance for the Betterment of Hong Kong, a pro-Beijing and pro-business conservative political party.
The 13th National People’s Congress concluded, however, without any definitive action on behalf of pangolins.
While importing pangolin scales and other pangolin body parts into China is prohibited under CITES, pangolin parts can be legally sold within China if the seller obtains a provincial permit.
From 2008 through 2015, permits were reportedly issued allowing the sale of about 27 metric tons of pangolin scales per year.
Will fear of disease help to reduce demand?
Pangolin conservationists hope that the emerging association of pangolins with the Wuhan coronavirus will suppress demand for pangolin scales and meat, allowing the endangered animals to recover.
Linkage to Severe Acute Respiratory Syndrome (SARS) has not wholly saved civets from cruel exploitation by wildlife consumers in southern China, but is believed to have helped to steeply reduce demand for civets.
Civets, however, unlike pangolins, are commonly raised in captivity, including by producers of so-called kopi luwak, or civet coffee, made from undigested beans collected from civets’ excrement.
Though civets are also poached throughout Southeast Asia, including for illegal export to China, and extirpated from the wild in some regions, civets are not at risk of extinction.
Leading Chinese scientist disappointed
The linkage of bats, civets, and SARS was eventually established by a Chinese Academy of Sciences Institute of Zoology team including Zhang Jinshuo, Ph.D.
“We later published many papers and popular science articles,” Zhang Jinshuo told Xinhua News, “urging everyone to stop eating wild animals and not to have too close contact with wild animals. Only the health of wild animals and the health of ecosystems can [secure] human health.”
Concluded Xinhua News on January 22, 2020, “To his disappointment, 17 years have passed, a new virus has appeared, and the bad habits of eating wild animals have not changed.”