The central Chinese city of Wuhan, where the first known COVID-19 cases were reported, may not be the place that the virus SARS-CoV-2 jumped to humans, Liang Wannian, leader of the Chinese side of the China-World Health Organization (WHO) joint team on origin tracing in Wuhan, told the South China Morning Post (SCMP) in an interview.

The next step in tracing the novel coronavirus' origins should target countries where the virus was found in animal, environmental and human samples before the Wuhan outbreak in 2019, as well as countries that export cold-chain products to the Chinese city's Huanan seafood market, the SCMP reported on Wednesday, citing Liang, also head of the expert group on the COVID-19 outbreak response and disposal at China's National Health Commission.

"We recommend that (the) WHO conduct a review and analysis of earlier suspected cases, earlier evidence found in animal and environmental studies that were published, to determine the scientific validity and reliability of the available evidence," said Liang.

Studies in multiple countries have suggested that the novel coronavirus could have been circulating outside China months before it was formally identified in Wuhan.

Blood samples taken in the northern region of Lombardy of Italy showed the presence of antibodies against the SARS-CoV-2 virus as early as in September 2019. An analysis of sewage water samples from November 2019 in Florianopolis, Brazil was found to contain traces of the novel coronavirus. Blood samples collected in the U.S. by the American Red Cross from December 13, 2019 to January 17, 2020 found SARS-CoV-2 antibodies.

Read more: Coronavirus found in multiple countries months earlier than in Wuhan: studies

Liang said the focus of the second-phase origin tracing work should be based on "publicly available research evidence."

As the China-WHO joint study concluded that the most likely pathway of the virus transmission was from an animal to an intermediary host and then humans, Liang said the studies should be conducted "in all countries where horseshoe bats and pangolins are distributed, particularly in areas where sampling is under-tested."

He called for an international cooperation mechanism to study and test wildlife species that carried diversified coronaviruses, including horseshoe bats, pangolins, civets, minks, ferrets and raccoons, with the focus on interviews and serological tests.

Liang also suggested the WHO reconsider the chain of transmission and transmission methods of SARS-CoV-2 "in the light of the latest research findings and keep abreast of the times," as the virus could be transmitted from humans or animals to objects and objects back to humans, which "updated our understanding of the transmission of respiratory infectious diseases," the SCMP reported.

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Liang reiterated in the interview that China was "fully capable" of doing its own research in origin tracing. He said China had already carried out studies to find out animal hosts before the WHO's field trip to China, but "all samples taken on farms that supplied Huanan seafood market came back negative. Antibody and coronavirus tests on livestock and wildlife animals collected between 2018 and last year also came back negative."

For the composition of the experts for the next phase of the study, Liang suggested the same experts who took part in the first study should also be involved to "ensure professionalism and continuity" and the host country should be able to decide who joins the team.

"In order to fully respect the national sovereignty of the next country conducting the new coronavirus tracing study, the final composition of the expert group should be mutually agreed between the host country and the WHO, with the leader of the expert group being a technical expert or official of the WHO Secretariat and an expert recommended by the host country," he said.

The effective working mechanisms and methods applied during the China-WHO joint study could be used in other countries in the next-phase study, which Liang said should be done in a way that ensured "maximum scientific accuracy, validity, legitimacy and fairness."