‘Covid-19 may have lain dormant around world’
The coronavirus may have lain dormant across the world and emerged when environmental conditions were right for it to thrive, rather than starting in China, an Oxford University expert believes.
Centre for Evidence-Based Medicine at Oxford senior associate tutor Dr Tom Jefferson says there is growing evidence that the virus was elsewhere before it emerged in Asia.
Last week, Spanish virologists announced that they had found traces of Covid-19 in samples of waste water collected in March last year, nine months before the disease was seen in China.
Italian scientists have also found evidence of the virus in sewage samples in Milan and Turin, from mid-December, many weeks before the first case was detected, while experts have found traces in Brazil from November.
Jefferson believes many viruses lie dormant throughout the globe and emerge when conditions are favourable. It also means they can vanish as quickly as they arrive.
“Where did SARS-1 go? It’s just disappeared,” he said.
“We need to start researching the ecology of the virus, understanding how it originates and mutates.
“There was a case in the Falkland Islands in early February. Now, where did that come from?
“There was a cruise ship that went from South Georgia to Buenos Aires and the passengers were screened and then on day eight ... they got the first case.
“Was it in prepared food that was defrosted and activated?”
Strange things like this happened with Spanish flu.
In 1918, about 30% of the population of Western Samoa died of Spanish flu and they hadn’t had any communication with the outside world.
“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.”
Jefferson believes the virus may be transmitted through the sewerage system or shared toilet facilities, not just through droplets expelled by talking, coughing and sneezing.
He and Centre for EvidenceBased Medicine director professor Carl Heneghan have called for an in-depth investigation similar to that carried out by John Snow in 1854, which showed cholera was spreading in London from an infected well in Soho.
Exploring why so many outbreaks occur at food factories and meatpacking plants could uncover major new transmission routes, they believe.
It may be shared toilets coupled with cool conditions that allow the virus to thrive.
“We’re doing a living review, extracting environmental conditions, the ecology of these viruses which has been grossly understudied,” Jefferson said.
“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.