“It is important to understand where this virus came from so we can understand how it can stop future outbreaks,” said Anne Rimoin, an infectious disease epidemiologist at UCLA.
“It̵7;s not about pointing fingers – it’s just understanding, so we know how to do better in the future,” Rimoin said.
As a result, on January 14, 2021, the World Health Organization sent a group of 17 international experts to Wuhan to work with Chinese scientists in an in-depth investigation of the origin of the virus.
Scientists have long said that SARS-COV-2 is of animal origin, meaning it tends to jump from animal to human when humans come into contact with animals infected with the virus. Such contact could include handling infected animals, eating or preparing animal markets, according to Rimoin.
However, experts don’t know exactly how the virus got into people, and reaching a solid conclusion on the origin of SARS-CoV-2 could take years. They do not yet know where or when the virus entered humans, and studies suggest that it may exist elsewhere in the world – possibly spreading low before the outbreak in Wuhan, China.
“You’re trying to recreate the event from the last year and a half with incomplete sampling and data,” Dr. W. Ian Lipkin, director of the Columbia University Center for Infection and Immunology, told ABC News. Used to know what happened before “
If earlier infectious disease investigations had any clue, the virus’s origins could be shrouded in mystery. The best comparison is the 2003 SARS outbreak, which was caused by the novel coronavirus (COVID-19) virus, its close cousin, and finally traced back to a single population of horseshoe bats.
But the search took more than five years. “I think they were quite lucky,” said Vincent Racaniello, a professor of microbiology and immunology at Columbia University’s College of Physicians and Surgeons, of the SARS investigation. The coming of the Ebola outbreak after looking for years, ”he added. “It’s not easy.”
The WHO-China joint report marks the first step in what is likely to be investigated for years, released last week. But the report remains mired in the conflict. Following the release, the United States and 13 other countries raised concerns about the report in a joint statement, citing international investigations. “Significantly lag and lack of access to complete and original information and examples”
But many experts said the report, although incomplete. But this is an important first step.
The researchers explored four main theories about virus transmission to humans, ranking them in order of likelihood. “Very promising” to “extremely unlikely”
Intermediate host theory: The theory suggests that the virus is transmitted from primitive pets to intermediate hosts such as mink, pangolin, rabbit, dog, raccoon, domestic cat, musk or ferret, and then infect humans directly through direct contact with the animal. Second.
Conclusion of the WHO-China investigation: “Very likely”
Animal Leak Theory: Animal distribution theory suggests that SARS-COVI-2 is transmitted directly from animals, likely bats, to humans. This transmission can occur through farming, hunting, or other close contact between humans and animals.
Conclusion of the WHO-China investigation: “It is possible”
Frozen food chain theory: The “cold-chain” theory suggests that animal-to-human transmission of SARS-CoV-2 can occur from contaminated frozen food. Frozen food products contaminated with animal waste containing SARS-CoV-2 can transfer the virus to humans without direct contact between humans and animals.
Conclusion of the WHO-China investigation: “It is possible”
Controversial laboratory leak theory reveals that ‘Extremely unlikely’
As part of the investigation, scientists have returned to the Huanan seafood market involving a group of first known cases in Wuhan. They also visited the Hubei Province Integrated Chinese and Western Medicine Hospital, where some of the first COVID-19 patients were treated and looked at virus sequencing data. The virus sequencing shows that different SARS-CoV-2 subspecies are spreading in Wuhan in December 2020.
“That once again shows that the virus could spread longer than most people know,” said Dominik Weyer, an epidemiologist and member of the WHO investigative team.
Virus ratings also show that the Huanan market is unlikely to be the primary source of the outbreak. Although many cases in the early stages are linked to the market. But there have also been cases involving other markets or none at all, the WHO-China report found.
“The market is definitely an amplifier. But it might not be the real source of the outbreak, ”Dwyer said.
Previous genome sequencing has shown that viruses are of natural origin, and the WHO-China team has rated the laboratory’s leak theory as “It is extremely unlikely.”
But WHO director-general Dr Tedros Adhanom Ghebreyesus said he doesn’t think the team’s theoretical assessments are comprehensive enough.
Further data and studies are needed to reach more definitive conclusions, Tedros said at a press conference on the report’s findings, noting that he was ready to deploy additional missions in conjunction with specialized experts to do so.
“Science cannot distinguish such things,” said Peter Daszak, zoologist and member of the WHO investigative team of the laboratory’s leak theory. “You can only show really positive results, you can’t prove negative. But what we’ve found is that escaping from the lab is extremely unlikely. “
The report found that the most likely pathway was the first theory that the virus was passed from bats to intermediate animals and then to humans.According to Daszak, the next steps for investigation could include going back to the case. First of the virus Abnormal investigations of market suppliers for antibodies And inspections of locations where animal concentrations are known to be at risk of SARS-COV-2.
Rimoin hopes that outbreaks will show that disease surveillance is the key to preventing future outbreaks, not just responding to them. As population growth and climate change drive more humans into animal habitats. “We’ll see more viruses from animals to humans, and we’ll see more incidents of disease,” Rimoin said.
“An infection anywhere can be an infection anywhere,” she said.
ABC News’ Sasha Pezenik, Sony Salzman and Eric Silberman contributed to this report.
Eric Silberman, MD, physician of internal medicine at Northwestern Memorial Hospital, is a supporter of the ABC News medical unit.