A World Health Organization team has visited the seafood market linked to the earliest Covid-19 cases in Wuhan on the third day of field work in a long-awaited mission to China to investigate the origins of the pandemic. A procession of vehicles carrying the team, made up of 14 scientists and WHO officials, was seen entering the barricaded Huanan Wholesale Seafood Market in midafternoon on Sunday. The WHO last week confirmed that the market would be among the sites visited by the group, which is on a month-long mission to investigate how the coronavirus infected humans and began spreading in Wuhan, where it was first identified in late 2019. Formerly a bustling shopping destination with hundreds of stalls, Huanan market was closed on January 1 last year after it was linked to a number of the earliest cases identified by doctors. It has not reopened and its precise role in the outbreak remains unclear. What if Covid-19 vaccines aren’t enough for herd immunity? The market, which sold wild animals in addition to seafood and produce, was originally considered a likely place for the new virus to have crossed over into humans. Scientists believe the virus came from an animal, probably a bat, before crossing over to humans either directly or via another animal. Medical reports have since shown that several of the earliest known cases had no apparent ties to the market. In May, Gao Fu, head of the Chinese Centre for Disease Control, said it appeared that the market was not where the virus originated and animal samples collected from the market that January were free from the virus. Over 300 samples taken from frozen animal carcasses at the market have been tested for the virus and were negative, according to a document published on the WHO website. But China has not publicly said whether any live wild animals were tested, and few further details of research into the market have been released. The international team, which is working with Chinese scientists, will review research related to markets as part of their mission, the WHO has said. Access to data, on animal studies and the earliest patients, is considered critical to its success. WHO director general Tedros Adhanom Ghebreyesus tweeted last week that he had asked Ma Xiaowei, the head of China’s National Health Commission, to ensure the international scientists “get the support, access and data needed” to “engage fully with their Chinese counterparts” in a Wednesday call. WHO team visits hospital that treated first Covid-19 cases in China’s Wuhan WHO team member Peter Daszak wrote on Twitter that the trip to Huanan market and another wholesale market visited earlier in the day were “very informative & critical for our joint teams to understand the epidemiology of COVID as it started to spread at the end of 2019”. “As you walk around Huanan market you feel the sense of historical importance of this place & a sympathy for the vendors & community who lost their livelihoods due to COVID,” said Daszak, a disease ecologist and president of US-based EcoHealth Alliance. As you walk around Huanan market you feel the sense of historical importance of this place & a sympathy for the vendors & community who lost their livelihoods due to COVID — Peter Daszak (@PeterDaszak) January 31, 2021 Some Chinese scientists have suggested that the virus could have been imported into Wuhan and the market via contaminated frozen seafood products, a controversial theory which the international community remains sceptical about. Chinese experts have linked several subsequent outbreaks over the past year to contamination from imported products, but the WHO says there is no evidence that people can become infected from food or food packaging. Sunday’s activities followed trips to two local hospitals that treated some of the first cases as well as a visit to an exhibition commemorating Wuhan’s efforts to battle the outbreak. The team ended a 14-day mandatory quarantine on Thursday – a period the scientists used to talk to their Chinese counterparts online. ‘Data doesn’t lie’: WHO team to start Wuhan investigation into Covid-19 origins The WHO has not released a full itinerary for the mission, but said on Thursday that field visits would include the Wuhan Institute of Virology, the Huanan market, and the Wuhan Centre for Disease Control laboratory. An intense spotlight has been trained on the international mission, as the origins of the virus have become highly politicised over the past year. In particular, the issue became part of the blame game between the United States and China. The US government, under the former president Donald Trump, suggested the virus could have come from a laboratory leak at the Wuhan Institute of Virology , which has conducted research into bat coronaviruses. China has vehemently denounced the claims, which scientists largely believe are unlikely. Beijing has repeatedly argued that the virus may not have emerged in China and said the search for the origins may need to take place in a number of countries. The WHO has said it is too soon to come to conclusions, but maintained that Wuhan is the logical place to begin the investigation. “All hypotheses are on the table as the team follows the science in their work to understand the origins of the COVID-19 virus,” the WHO said last week.