Delegates attend the 73rd World Health Assembly via video link in Beijing, capital of China, May 18, 2020.Photo:Xinhua

WHO's admission that Wuhan may not be the origin of COVID-19 may put to rest conspiracy theories that have put the central Chinese city and China in a bad light over the virus' origin, Chinese epidemiologists said. They urged for more research on transmission channels and virus host which are vital for epidemiologic studies. 

China's door is wide open for more WHO epidemiologic studies, while other countries should follow if the onus falls on them, Chinese experts said. They believe countries like the US, which tops the world in number of confirmed COVID-19 cases, and certain European countries, where the virus was identified as early as last year, should also undergo a thorough investigation on the virus origin for a clearer picture.

First alarm



Wuhan may not be the origin of the novel coronavirus, senior WHO official Mike Ryan said on Monday, announcing extensive studies to track down the animal species that transmitted the virus to humans.

"The fact that the fire alarm was triggered doesn't necessarily mean that was where the disease crossed from animals to humans," Ryan said at a press conference in Geneva.

His comments came as the organization's team to China concluded its weeks-long mission, which was to lay the groundwork for further joint efforts at identifying the origin of the coronavirus.

China's National Health Commission said on Tuesday that Chinese experts had kept in close contact with the two WHO experts, who stayed in China from July 11 to August 2, about possible transmission channels, and to identify the source of COVID-19, and the host of the virus. 

Mounting facts and scientific evidence are emerging to support the hypothesis that the coronavirus did not originate in Wuhan, Zeng Guang, chief epidemiologist of the Chinese Center for Disease Control and Prevention, told the Global Times, citing a sample of the virus found in Barcelona waste water collected as early as March 2019, and virus spotted in a sewer in Brazil in November last year.

The fact that the outbreak was first reported in Wuhan, not those countries may have  something to do with the transmission medium or host of the virus, said Yang Zhanqiu, deputy director of the pathogen biology department at Wuhan University.

Zeng and Yang believe that the virus must have jumped from wild animals to human beings. Yang said they must identify the animal host, and under what conditions it was passed on.   

Chinese virologist Shi Zhengli, who is also director of Wuhan Institute of Virology wrote to Science magazine on July 15 that based on research done by her team and international scientists, the coronavirus likely originated from bats, and evolved through one or several hosts, and eventually jumped to humans. 

But it is still unclear how the virus got to humans, Shi noted. 

Ever since the outbreak was first reported in the Huanan wet market in Wuhan, rumors and speculations have been circulating that the market, which was shut down in January, was where the virus had originated from. 

However, Shi said that she and other experts has tested samples collected from the market, and only found the virus on environmental samples, such as doorknobs, floor and sewage. No virus was found on animals, which made Shi conclude that maybe the market was only where many COVID-19 patients were found in the early stage.

Almost a third of early stage COVID-19 patients had no direct contact with the wet market, said Wang Guangfa, a leading Chinese respiratory expert at Peking University First Hospital in Beijing, and also a member of the first batch of national medical experts dispatched to Wuhan in early January, told the Global Times. 

A doctor who works at Wuhan University's Zhongnan Hospital, who declined to identify himself, told the Global Times that they received patients with symptoms of unknown pneumonia, but had no direct contact with Huanan market in late December. But since both the hospital and Wuhan authorities was new to the virus then, and lacked clinical experience on the new virus, they only screened and rounded up those linked to the market.

Only after the coronavirus test kits were widely used did doctors conclude that those patients suffered from suspected COVID-19 symptoms, Wang said. 

As knowledge of the coronavirus began to grow, many foreign experts also tend to believe the Huanan wet market may not be the origin of the virus. Robert Garry, a professor at the Tulane University School of Medicine, told ABC News in March that "Our analyses, and others too, point to an earlier origin than that." "There were definitely cases there, but that wasn't the origin of the virus."

The Huanan Seafood Market in Wuhan, capital of Central China's Hubei Province. Photos: CNS photo

Further identification work

WHO director general Tedros Adhanom Ghebreyesus said on Monday said that epidemiological studies will begin in Wuhan to identify the potential source of early infections.

Wang Wenbing, a spokesperson of China's Ministry of Foreign Affairs, said on Tuesday that China and the WHO are maintaining communication on the next step of the research plan on coronavirus traceability. 

Yang said that as the viral contagion has been wiped out in Wuhan for nearly two months, and most environmental samples are already gone, the WHO team may focus on finding the patient zero, and patients who showed symptoms at an early stage or who traveled  to other countries about the time of the outbreak.

The virologist also said finding the possible host and research on wild animals to identify the transmission channels are also important. 

Wuhan has conducted an epidemical study in mid-April following the lifting of the citywide lockdown. The study included samples from 11,000 residents who had received nucleic acid and serum tests.

The results of the study have yet to be published. An official surnamed Wang from Wuhan's health commission told the Global Times that the study also helps in virus tracing work. 

Zeng believes that to get a clearer picture of virus tracing, the WHO should also conduct similar epidemiological studies in other countries, such as the US and certain European countries. 

The WHO should have a top-level design to identify the source of the coronavirus. First, all evidence on virus origin must be collected globally, and then be ordered according to when they happened, after which teams must be sent to those countries for scientific identification and research, Zeng said. 

China is cooperating with WHO on identifying the origin of the coronavirus, and hopes other countries will do the same when the onus falls on them, the epidemiologist said.