WHO. Photo: VCG

While the WHO has indicated there may be more than one patient zeroes as coronavirus has been identified in many different countries and said they plan to send experts to China to investigate the virus origin, Chinese experts noted that the virus origin has become a problem requiring global cooperation as multiple theories pointed to the need for global efforts to solve the puzzle.

They also said that as the epidemic in more and more countries has subsided, it is time to call on more epidemic-stricken nations to participate in and face up to the scientific question.

In response to a question about the WHO experts traveling to China soon for work related to COVID-19 origins, Zhao Lijian, a spokesperson of the Chinese Foreign Ministry said on Tuesday that since COVID-19 broke out, China and WHO have been in communication and cooperation on the origin tracing of the virus. While tracing the origin domestically, China has been earnestly implementing WHA resolutions. 

"We are the first to invite WHO experts in for origin-tracing cooperation." Zhao said, adding that "We hope all relevant countries will adopt a positive attitude and cooperate with WHO like China does, making contributions to global origin-tracing and anti-epidemic cooperation." 

The remarks came at a time when more evidence points to the existence of the virus long before the Wuhan outbreak. WHO experts also hinted that there are more than one patient zeroes. 

There may be more than one cases of patient zero in some situations, because there may be more than one species breach. We're increasingly seeing that viruses have been identified in many different countries, Mike Ryan, the WHO's top emergencies expert said at a Monday press briefing.

How does that disease breach that barrier into the human species? It may have been a single event, or been multiple events. Those events may have occurred in one particular time or over a range of different times. If the novel coronavirus exists among animals, it may spread across species multiple times, Ryan said.

In March and summer, the origin tracing of the virus was focused on China, but more and more evidence, plus WHO's latest speculation on patient zero, suggested that more professionals are beginning to realize that Wuhan is the place the disease was first identified, but probably not the place where the virus originated from, Zeng Guang, chief epidemiologist of the Chinese Center for Disease Control and Prevention, told the Global Times on Tuesday. 

China's mechanism of detecting pneumonia for unknown reasons helped Wuhan identify the new infectious disease and virus. But the fact that it can sweep the world in such a short period of time is a strong indication that the novel coronavirus may have existed in multiple places for uncertain periods of time, Zeng said.  

"When and where did the virus start circulating? Tracing the virus cannot answer all questions, but it is very likely that the virus had co-existed in multiple places before being spotted in Wuhan," Zeng noted.

Amid continuous reports of infections related to international cold-chain deliveries, some top Chinese experts have also suggested that the possibility cannot be ruled out that the Wuhan outbreak was also caused by international cold-chain deliveries.

A new study by the National Cancer Institute of Milan recently found the novel coronavirus in blood samples collected in October 2019, and previous research led by the University of Barcelona showed the presence of the virus in samples of sewage in the city in March 2019.

"Those academic studies should be part of seeking virus origins. If we could combine the efforts of scientists across these countries and call on them to participate in the scientific investigation, we might be much closer to the truth on the virus' origin," Wang Guangfa, a respiratory expert at Peking University First Hospital, who had been to Wuhan in the early stage of the outbreak, told the Global Times on Tuesday.

Wang said the WHO-led origin tracing should be done in any country being stricken by the epidemic, including Italy, Spain, other European nations and the US. 

"Our task is to find how the virus jumps to human beings, whether from animals, and to find patient zero," Wang said. 

"Finding where the virus originated from is not political, but a scientific matter. Inviting international experts to China shows China's consistent open altitude in seeking the virus origin. It doesn't imply China is the origin, Wang stressed.

Ryan said it's important for its international team to visit China to look into the origins of the coronavirus, saying the UN health agency has been reassured such a trip will happen as soon as possible, the Associated Press reported.

The Global Times found when the Chinese foreign ministry on July 8 answered questions on inviting experts for origin tracing to China, it also mentioned the importance of conducting similar trips to other countries and regions based on need.

Origin-tracing is a scientific issue that should be studied by scientists through international research and cooperation across the world. It is also the view of WHO that it is an ongoing process probably concerning many countries and localities, the ministry had said.

Since the Wuhan outbreak, China has always been holding a very open altitude on origin tracing, including sharing data with the WHO and other countries. The world should hold such an attitude to help solve mysteries concerning the virus, experts noted.

Chinese academics are open to do research on origin tracing, and China has never been politicizing the issue, Wang pointed out, hoping other media and countries stop throwing mud on China and blame China. "No country can manage alone or stand aloof facing the health crisis, when more evidence is backing the multiple-source theory."