A novel coronavirus outbreak that originated in Wuhan, China, has killed at least 2,700 people and infected more than 80,000 others.
The Huanan Seafood Wholesale Market in Wuhan may have been the starting point of this outbreak. It was shuttered January 1.
At many wet markets, meat, poultry, and seafood are sold alongside live animals for consumption.
On February 24, China's top legislature banned the buying, selling, and eating of wildlife.
The novel coronavirus and the SARS outbreak of 2003 have two things in common: Both are from the coronavirus family, and both most likely started in wet markets.
At such markets, outdoor stalls are squeezed together to form narrow lanes, where locals and visitors shop for cuts of meat and ripe produce. A stall selling caged chickens may abut a butcher counter, where meat is chopped as nearby dogs watch hungrily. Some vendors hock hares, while seafood stalls display glistening fish and shrimp.
Wet markets put people and live and dead animals — dogs, chickens, pigs, snakes, civets, and more — in constant close contact. That makes it easy for zoonotic diseases to jump from animals to humans.
"Poorly regulated, live-animal markets mixed with illegal wildlife trade offer a unique opportunity for viruses to spill over from wildlife hosts into the human population," the Wildlife Conservation Society said in a statement.
In the case of SARS and the new coronavirus disease, called COVID-19, bats were the original hosts. The bats then infected other animals, which transmitted the disease to humans. The coronavirus has now killed at least 2,700 people and infected more than 80,000 others. (For the latest totals, see Business Insider's live updates here.)
The market where the current outbreak may have started, the Huanan Seafood Wholesale Market in Wuhan, was shuttered January 1. Wuhan authorities banned the trade of live animals at all wet markets there soon after, and China announced a temporary national ban on the buying, selling, and transportation of wild animals in markets, restaurants, and online marketplaces across the country as well.
On Monday, that ban became permanent. Farms that breed and transport wildlife to wet markets were also quarantined and shut down.
Here's what Chinese wet markets looked like before these new policies went into effect.
The Huanan Seafood Wholesale Market in Wuhan closed January 1 after it was found to be the most likely starting point for the outbreak of the new coronavirus.
NOEL CELIS/AFP via Getty Images
A 61-year-old man was the first person to die from the virus. According to Bloomberg, he was a regular shopper at the Huanan wet market, which sold more than seafood.
Reports indicate that before the Huanan market closed, vendors there sold seafood, meat, and live animals, including chickens, donkeys, sheep, pigs, foxes, badgers, bamboo rats, hedgehogs, and snakes.
Teh Eng Koon/AFP via Getty
Wet markets like Huanan are common in China. They're called wet markets because vendors often slaughter animals in front of customers.
"That means there's a lot of skinning of dead animals in front of shoppers and, as a result, aerosolizing of all sorts of things," Emily Landon, an infectious-disease specialist at University of Chicago Medicine, wrote in an article.
A January report challenged the idea that virus emerged in the Huanan wet market, however.
Robert Ng/South China Morning Post/Getty
Chinese scientists found that the first reported case of the Wuhan coronavirus from December had no link to the wet market, according to Science, which cited a report published in the medical journal The Lancet.
What's more, 13 of 41 coronavirus cases had no link to the Huanan marketplace, the researchers said. More research is needed to pinpoint the outbreak's starting point with certainty.
Wuhan authorities banned the trade of live animals at wet markets in the city on January 22.
David Wong/South China Morning Post/Getty
Much of China's wildlife trade was already illegal: China's Wildlife Protection Law bans the hunting and selling of endangered species but doesn't apply to all wild animals. But the practice persisted because of lax enforcement and legal loopholes, such as inconsistencies in species' names and online sales of exotic wildlife as pets.
Before the new ban was instated, the Chinese Communist Party announced plans to crack down on illegal wildlife markets and trade across the country, recognizing "shortcomings" in its response to the outbreak.
Some experts have applauded the permanent ban. "The government has signaled that it wants to take immediate action to prevent any future outbreaks of diseases that spread from animals to humans," Li Zhang, a conservation biologist at Beijing Normal University, told Nature.
Li added that wildlife trade and consumption was both a direct threat to animals and a major public-health risk.
Since the outbreak began, Chinese authorities have shut down 20,000 farms raising peacocks, civet cats, porcupines, ostriches, and wild geese, The Guardian reported.
The permanent ban applies to wildlife already protected by law, other terrestrial animals of "important ecological, scientific and social value," and terrestrial wild animals in breeding farms, according to China's People's Daily. It does not affect the sale or consumption of aquatic animals, livestock, or poultry.
"There has been a growing concern among people over the consumption of wild animals and the hidden dangers it brings to public health security since the novel coronavirus disease (COVID-19) outbreak," Zhang Tiewei, a spokesman for China's top legislature, told Reuters on Monday.
Teh Eng Koon/AFP/Getty
Zhang added that the decision came at a "critical moment for the epidemic prevention and control."
The close proximity of shoppers to stall vendors and live and dead animals in wet markets has made them breeding grounds for zoonotic diseases in the past.
Felix Wong/South China Morning Post/Getty
Three-quarters of new or emerging infectious diseases in people come from animals, according to the Centers for Disease Control and Prevention.
SARS originated in wet markets in the province of Guangdong. It killed 774 people across 29 countries from 2002 to 2003.
In the case of SARS, humans caught the virus from weasel-like mammals called masked palm civets.
Dustin Shum/South China Morning Post via Getty
But the civets weren't the original hosts of the disease.
Researchers figured out that SARS originally came from a population of bats in China's Yunnan province.
"Coronaviruses like SARS circulate in bats, and every so often they get introduced into the human population," Vincent Munster, a virologist at the Rocky Mountain Laboratories, told Business Insider.
Bats can pass along viruses in their poop: If they drop feces onto a piece of fruit that a civet then eats, the civet can become a disease carrier.
Bats and birds are considered reservoir species for viruses with pandemic potential, according to Bart Haagmans, a virologist at the Erasmus Medical Center in Rotterdam, Netherlands.
Ronny Adolof Buol / AFP/ Getty
"Because these viruses have not been circulating in humans before, specific immunity to these viruses is absent in humans," Haagmans told Business Insider.
Experts think the new coronavirus also originated in bats, but they haven't confirmed the intermediary animal species that passed it to people.
"There's an indication that it's a bat virus, spread in association with wet markets," Munster said.
When researchers compared the genetic code of the new coronavirus with other coronaviruses, they found it to be most similar to bat coronavirus samples. One study found that the new coronavirus shares 96% of its genetic code with coronaviruses circulating in Chinese bat populations.
The most likely intermediary-species candidates are pigs, civets, and pangolins.
A group of researchers from South China Agricultural University found that samples of coronaviruses taken from wild pangolins and those from infected coronavirus patients were 99% identical. But this research has yet to be published or confirmed by other experts.
The pangolin is an endangered mammal that resembles a scaly anteater. The trade and consumption of pangolins is illegal under China's Wildlife Protection Law, but they are still known to be roasted and eaten in China, Vietnam, and parts of West Africa. Pangolin scales have also been used in traditional Chinese medicine.
A group of scientists who edit the Journal of Medical Virology initially suggested the culprit could be the Chinese cobra, but many other scientists say that's highly improbable.
Cui Jie, a virologist who was on a team that identified SARS-related viruses in bats in 2017, told Nature that this coronavirus strain was clearly a "mammalian virus."
"They have no evidence snakes can be infected by this new coronavirus and serve as a host for it," Paulo Eduardo Brandão, a virologist at the University of São Paulo who is investigating whether coronaviruses can infect snakes, told Nature.
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According to the World Health Organization, people caught those bird flus via direct contact with infected poultry in China. The diseases killed 1,000 people globally.
K. Y. Cheng/South China Morning Post/Getty
These pandemics "are more likely to originate in the Far East because of the close contact with live animals [and] the density of the population," Hyzler added. His firm offers risk-management solutions for global travelers.
Since December 31, more than 80,400 COVID-19 cases have been reported across 38 countries, including the US. Symptoms include sore throats, headaches, and fevers, as well as pneumonialike breathing difficulties.
Aria Bendix contributed reporting to this story.
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