PARIS - After Thailand detected its second case of a mysterious SARS-linked virus this week following confirmed cases in China and Japan, here are a few key points about coronavirus.
What is coronavirus?
The UN's health agency says that the outbreak of the disease in the Chinese city of Wuhan is a never-before-seen strain belonging to a broad family of viruses ranging from the common cold to more serious illnesses such as SARS.
According to Arnaud Fontanet, head of Paris' Institut Paster department of epidemiology, the new strain is the seventh known type of coronavirus that humans can contract.
"We think that the source may have been animals sold at market and from there it passed to the human population," he told AFP.
There is so far no indication of human-to-human transmission of the virus.
The outbreak has caused alarm because of the link with SARS (Severe Acute Respiratory Syndrome), which killed 349 people in mainland China and another 299 in Hong Kong in 2002-2003.
Fontanet said the current virus strain was 80 percent genetically identical to SARS.
At least 40 cases have been reported in Wuhan this year, and the outbreak has already claimed two lives.
Time to panic?
Fontanet said that the coronavirus appears to be "weaker" than SARS in its current form, but cautioned that it could mutate into a more virulent strain.
"We don't have evidence that says this virus is going to mutate, but that's what happened with SARS," he said.
"The virus has only been circulating a short time, so it's too early to say."
As for person-to-person transmission -- a key hallmark of pandemics -- it may also be too early to tell.
Investigations carried out into the 700 or so people in Wuhan who came into contact with quarantined cases showed no one had passed on the virus, with the possible exception of one woman who claims she never went to the seafood market where the outbreak is thought to have started.
Authorities have pronounced the risk of human transmission "weak" but not impossible.
Fontanet said the fact that the virus had spread beyond China was "starting to make us fear that interhuman transmission is possible."
WHO has not recommended any specific measures for travelers or restrictions on trade with China but believes that new coronavirus cases in other countries are likely.
The best way of containing any disease outbreak is to rapidly confirm the source, according to Raina MacIntyre, from the University of New South Wales in Sydney.
"Tests are being done on animals in the Wuhan region and they should provide some insight," she said.
Experts said authorities must be vigilant and monitor travelers coming to and from Wuhan for signs of breathing problems.
Fontanet said health workers in China had responded admirably by rapidly carrying out testing among patients and linking the cases to the market in question.
"We've learned some lessons from SARS. We're better armed and more reactive," he said.
Adam Kamradt-Scott, an expert in the spread and control of infectious diseases the University of Sydney, said China had "has been quick to share the genome sequencing of this novel coronavirus.
"This has enabled the identification of this new case in Japan," he said.
Fontanet said that such transparency was different to the start of the SARS epidemic, when China "hid the story for two or three months" at the start of the outbreak.