New virus close to SARS virus scrutinized by world authorities - France 24

Paris (AFP)

What is the new virus detected in China? Can it cause an epidemic comparable to that of SARS? These questions agitate the world scientific community when three patients died of respiratory problems and cases appear in other countries of Asia.

- What virus, what effects?

Never observed before, this virus belongs to the vast family of coronaviruses. It is the "seventh coronavirus capable of giving clinical manifestations in humans", explains to AFP Arnaud Fontanet, head of the unit for epidemiology of emerging diseases at the Institut Pasteur in Paris.

Its origin seems to be in a market in Wuhan, a Chinese city of 11 million inhabitants, closed on January 1. "We assume that the source was animals sold in this market and that there was passage in humans," says Professor Fontanet.

From a genetic point of view, there is "80% similarities" between the two viruses, notes Professor Fontanet, and both cause pneumonia (respiratory diseases).

So far, three patients have died, all in China. The first two were 61 and 69 years old, the age of the third was not specified.

- What transmission from human to human?

This is the central question, on which we still lack certainty.

Since the first cases, the Chinese health authorities judge the risk of a transmission of the virus between humans "low", even if it is "not excluded".

They are based on the fact that the tests did not show contamination of the entourage or the caregivers of the first cases, with the exception of a woman whose husband worked on the famous market, while she -Even assure that I have never been there.

But the situation has changed in recent days. Limited to around 40 before the weekend, the number of known cases is now officially estimated at 205, including 201 in China (198 in Wuhan, two in Beijing and one in Shenzhen). The other cases have been identified in Japan (1), Thailand (2) and South Korea (1), in patients who had all previously stayed in Wuhan.

And scientists believe that number is largely underestimated: researchers at Imperial College London estimate that more than 1,700 cases have been estimated to have occurred in Wuhan since January 12, based on statistical projections.

"Uncertainties remain, but it is clear that there is some degree of human-to-human transmission of the virus," said Dr. Jeremy Farrar of the British research foundation Wellcome.

"It is possible that some patients may have little or no symptoms, which would mask the real number of people infected and therefore the extent of transmission between humans," he said.

- Will the epidemic spread?

"Taking into account travel habits around the world, new cases in other countries (than China) are probable," warns the WHO, a few days before the big crossovers of the Chinese New Year.

"It is very difficult to predict the extent of the epidemic at this stage, but it is clear that it is spreading. We are all much more concerned than a few days ago," admits Dr. Mike Turner, from Wellcome.

This is why several countries, including the United States, have set up a surveillance system at airports to filter travelers from Wuhan and isolate them if they have respiratory symptoms.

Furthermore, to contain the epidemic, it is necessary to find its source, that is to say the animals which are the reservoirs of the virus.

This could help find out if there are fireplaces in markets other than the first, and take further action.

In the case of SARS, "it was by prohibiting the consumption of civets (a mammal whose meat is appreciated in China, note) and by closing livestock farms that we could have prevented any reintroduction" of the virus, recalls Professor Fontanet.

- A danger comparable to Sras?

"The gravity seems weaker than the SARS", judges Professor Fontanet.

But theoretically, that could change. "We don't really have an argument to say that this virus will mutate, but that's what happened with SARS", whose virus had evolved after its appearance to become "more transmissible and more virulent" , according to the French specialist, even if it remains for the moment "purely speculative".

- A reaction to the pitch?

"We have learned the lessons of SARS: we are better armed, more responsive," said Professor Fontanet.

According to him, the Chinese health authorities accomplished "a tour de force" by locating that an "abnormal problem was in progress" at the time of the first diagnoses in mid-December, then by making the connection between these patients and the market.

In addition, China "quickly realized and shared with the rest of the world the genetic sequence of this new coronavirus," added Professor Adam Kamradt-Scott, of the University of Sydney. This made it possible to set up a specific test to identify cases.

"Compared to SARS, one of the first differences is the transparency (of China) vis-à-vis the WHO", concludes Professor Fontanet, since in 2002-2003, "history had been hidden "for several months.

© 2020 AFP