Coronavirus pandemic: Where did COVID-19 originate? New evidence suggests it may not be Wuhan's wet market
While there is enough evidence to prove that the virus jumped from animals -- bats to an intermediary animal and then to humans -- scientists do not know where the virus took hold
As the world tries to put every resource into containing the outbreak, one question continues to puzzle scientists: Where did the new coronavirus come from?
New evidence suggests that humans may not have picked up the virus from Wuhan's infamous wet market. The latest study of the first 366 children who caught the infection in early January found no connection to the market.
While there is enough evidence to prove that the virus jumped from animals -- bats to an intermediary animal and then to humans -- scientists do not know where the virus took hold.
“If you don’t understand where it came from, then it’s hard to make policies, procedures, to prevent it from happening again,” Krutika Kuppalli, an infectious disease physician and Emerging Leader in Biosecurity fellow at the Johns Hopkins University Center for Health Security, told Vox.
China alerted the World Health Organization (WHO) of a pneumonia-like illness circulating in Wuhan. It did not take long for scientists from China to release the genetic information of the virus.
Since then, researchers have been racing against time to develop a vaccine. The US initiated its first clinical trial on March 16 -- researchers accomplished this in a little over three months. There are more vaccine trials in the pipeline all of which will take at least a year before it is made available.
Why the virus may not have come from the wet market?
To understand that, scientists play detective as they try to identify the first few COVID-19 patients. This is proving to be a challenge given that the virus moved discreetly.
The first clue stemmed from a study that looked at the first 41 hospitalized patients in Wuhan. Something stood out in the data: 13 of the first 41 patients had nothing to do with the Hunan market.
“That’s a big number, 13, with no link,” Daniel Lucey, an infectious disease specialist at Georgetown University, told Science.
The study suggests that the virus may have been circulating quietly in November. And then suddenly the virus infected a bunch of people with links to the Huanan Seafood Wholesale Market was discovered in late December. “The virus came into that marketplace before it came out of that marketplace,” Lucey explains.
This is not the only study. According to researchers from Xishuangbanna Tropical Botanical Garden under the Chinese Academy of Sciences and the Chinese Institute for Brain Research, the virus was brought into the market from elsewhere. The market, in turn, may have helped the virus spread and circulate efficiently.
“The crowded market then boosted SARS-CoV-2 (the new coronavirus) circulation and spread it to the whole city in early December 2019,” the authors wrote in their study.
They arrived at this finding after looking at the genetic information of 93 viral samples provided by 12 countries. By scanning the genes, the team hoped to retrace the steps of the virus.
From the data, they found that the virus may have been moving among people in late November or early December. "The genomic evidence did not support the Huanan market as the birthplace of SARS-CoV-2," the authors wrote.
They added that figuring out whether the Huanan market is the only birthplace of SARS-CoV-2 is important to find its source and determine the intermediate animal. This, according to them, can help experts control the epidemic and prevent it from spreading again.
Even a study of children -- a total of 366 hospitalized -- who caught the infection in early January, makes the case against the Huanan market being the source of the outbreak. Neither the children nor the parents had any connection with the market.
What is more, one patient was not from Wuhan. "It is worth mentioning that we unexpectedly found a case of Covid-19 in one patient (Patient 3) who resided outside Wuhan; this patient had illness onset on January 2, 2020," the authors wrote in their study. The child hailed from the Yangxin area of Huangshi and had not traveled outside the city in the month before the child caught the illness, they added.
Finding a child who developed the disease outside of Wuhan in the early days of the outbreak suggests, "it didn’t just start in a fish market," Dr. Matthew B. Frieman, from the University of Maryland School of Medicine, tweeted.