The coronavirus may have been lying dormant across the world until emerging under favourable environmental conditions, rather than originating in China, an expert has claimed.
Dr Tom Jefferson, from the Centre for Evidence-Based Medicine (CEBM) at Oxford University, has pointed to a string of recent discoveries of the virus’s presence around the world before it emerged in Asia as growing evidence of its true origin as a global organism that was waiting for favourable conditions to finally emerge.
Traces of COVID-19 have been found in sewage samples from Spain, Italy and Brazil which pre-date its discovery in China. A preprint study, which has not been peer reviewed, claims to have found the presence of SARS-CoV-2 genomes in a Barcelona sewage sample from 12 March 2019.
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In an interview with The Daily Telegraph, Dr Jefferson has called for an investigation into how and why the virus seems to thrive in environments such as food factories and meatpacking plants.
Along with CEBM director Professor Carl Heneghan, Dr Jefferson believes this could potentially uncover new transmission routes, such as through the sewerage system or shared lavatory facilities.
He told the paper: “Strange things like this happened with Spanish Flu. In 1918, around 30 per cent of the population of Western Samoa died of Spanish Flu and they hadn’t had any communication with the outside world.” [It is however believed that the Spanish Flu arrived at the island nation in the cargo ship Talune in 1918]
“The explanation could only be that these agents don’t come or go anywhere. They are always here and something ignites them, maybe human density or environmental conditions, and this is what we should look for,” said Jefferson.
“There is quite a lot of evidence of huge amounts of the virus in sewage all over the place, and an increasing amount of evidence there is faecal transmission.
“There is a high concentration where sewage is 4°C, which is the ideal temperature for it to be stabled and presumably activated. And meatpacking plants are often at 4°C.
“These outbreaks need to be investigated properly.”
Reader Q&A: Why don’t viruses like the flu die off when no one is ill?
Asked by: Andrew Cirel, via email
Strictly speaking, viruses can’t ‘die off’ as they’re just inanimate strips of genetic material plus other molecules. But the reason that they keep coming back is because they’re always infecting someone somewhere; it’s just that at certain times of the year, they’re less able to infect enough people to trigger a full-blown epidemic.
Many viruses flare up during the winter because people spend more time indoors in poorly-ventilated spaces, breathing in virus-laden air and touching contaminated surfaces. The shorter days also lead to lower levels of vitamin D, and this weakens our disease-fighting immune system. Experiments also suggest that the flu virus in particular remains infectious for longer in low temperatures.
But even when conditions aren’t ideal, viruses will find enough people to infect to ensure their survival, until they can come roaring back in an epidemic.