Having squashed their first outbreak, tensions are rising in Beijing as new cases of Covid-19 started to emerge last week. Reports indicated that traces of SARS-CoV-2 had been found on a chopping board used for salmon in a wholesale market, sparking fears that the popular seafood could be the source of the fresh cases. Suppliers scrambled to halt trade in the fish with reserves being dumped and the ensuing panic triggering widespread restaurant cancellations. Chinese officials have since stated that the source of the SARS-CoV-2 infections is either contaminated imported meat or fish or from an infected market worker, but it did little to settle consumers' fears who continue to avoid the once-popular seafood.
The capital has reported 79 new cases of Covid-19 since last Thursday, according to a report on NPR, which has put the city back under lockdown in an attempt to stem a possible second wave of the outbreak. All of the cases were tied to the Xinfadi wholesale food market, which provides 1,500 tons of seafood to restaurateurs every day, as well as other meats and produce. The chairman of the market announced the discovery and the market was sealed off on Saturday.
An initial test of 517 workers from the market revealed 45 positive results for Covid-19. Authorities then went on to test a further 5,803 people from the Xinfadi on Saturday, all of which tested negative, and took 2,383 samples from surfaces within the market. They have requested that any visitors to the market present themselves for testing in an attempt to trace if any further asymptomatic cases, of which there have so far been 48, have yet to be traced.
An epidemiologist for China's Center for Disease Control and Prevention (CDC) told Chinese media that of the samples taken from market surfaces, investigations revealed that the SARS-CoV-2 variants were more similar to the strains widespread in Europe than the variant most reported in China, implying it had traveled to Beijing from elsewhere though not necessarily Europe. Wu Zunyou, also an epidemiologist with China's CDC, said in a statement that the Covid cases linked to the market were most likely transmitted from seafood and meat products that were contaminated after being handled by infected people elsewhere, but it hasn't yet been ruled out that the infection could have come in via one of the market workers who then handled the contaminated items.
There is currently no evidence to support the idea that living salmon can transmit Covid-19, meaning SARS-CoV-2 would have needed to survive long enough on the contaminated salmon in order to spread in the same way pathogens on contaminated surfaces such as door handles do. Food authorities have, however, previously stated that food is not a likely source of Covid as even if it were contaminated, the virus should be inactivated through thorough cooking, disinfection, or preparation.