Coronavirus may be "hitching a ride" around the world with the $1.5trn global food market, according to a leading scientist, leading to outbreaks at wholesale markets and processing plants.
It is "feasible" that the virus can survive on the surface of frozen food or packaging, infecting the worker who first handles the imported foodstuffs, says Dr Dale Fisher, chair of the World Health Organization's Global Outbreak Alert and Response Network.
“It’s hitching a ride on the food, infecting the first person that opens the box,” Dr Fisher told Bloomberg. “It’s not to be confused with supermarket shelves getting infected. It’s really at the marketplace, before there’s been a lot of dilution.”
Speaking to The Telegraph, he stressed that he did not want to start a "food scare". Consumers were not at risk via this route, he said, rather workers at markets and in processing plants.
"There is a lot of circumstantial evidence for this - infections in markets, and China finding the virus on packaging. And in countries which have not had a case for a long time, and the virus reappears, we don't have a good explanation for that at the moment and it's not right to just dismiss all this evidence," he told The Telegraph.
Outbreaks have been traced back to markets in China, Peru, and New Zealand in recent months - often in places where there have been no cases for some time - although there is controversy over whether the virus can actually be transmitted through touch.
The World Health Organization (WHO) says there are still no recorded incidents of surface transmission. However, a number of studies have recently suggested that the virus can survive on surfaces for significant periods of time in laboratory conditions. It does particularly well in the cold, dark conditions that are also critical in the global food distribution industry.
Dr Fisher's team published a study in August which found that coronavirus survived in these conditions on pork, chicken and salmon for up to three weeks in their experiments.
He said transmission in the real world was "freakish", but the study added: "The international food market is massive and even a very unlikely event could be expected to occur from time to time."
Dr Julian Tang, a consultant virologist at the Leicester Royal Infirmary and honorary associate professor at the University of Leicester, who was not involved in the study, said more work needed to be done on the links and it remained a "tricky question".
"Can infection occur by this route? Yes, of course this is possible," he said.
"We’ve said more generally that touching contaminated surfaces then touching really inside your eyes, nose [and] mouth, can cause infection, but we don’t think this is the main way SARS-Cov-2 spreads.
"The frequent hand washing message still applies - and if performed after touching contaminated food or packaging, should reduce this risk."
He said workers should be washing their hands before and after touching meats anyway, for general food hygiene purposes, or wearing gloves. In Asia, workers in warehouses wear masks.
"Controlling the spread of Covid-19 is not just down to one action - a combination of everything is required to deal with this virus: hand-washing, masking, social distancing, reducing contacts, and ventilation, et cetera.
"This angle on the possible transmission of the virus on food and food packaging just highlights and reinforces the need for this combined approach."
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