Here is some of what we know - and don't know - about thevirus:

WHERE DID THE VIRUS COME FROM?

The virus is believed to have originated late last year in afood market in the Chinese city of Wuhan that was illegallyselling wildlife. Health experts think it may have originated inbats and then passed to humans, possibly via another species.

The World Health Organization (WHO) was alerted to severalcases of pneumonia in Wuhan at the end of December. Chineseauthorities confirmed they had identified a new virus a weeklater.

HOW DANGEROUS IS IT?

The new virus, identified by scientists as 2019-nCoV, is acoronavirus, a family of viruses that include the common coldand more serious diseases such as Severe Acute RespiratorySyndrome (SARS).

Coronavirus infections have a wide range of symptoms,including fever, cough, shortness of breath, and breathingdifficulties.

It is unclear how deadly the new virus is. Although severecases can cause pneumonia and death, there may be many cases ofmilder disease going undetected. Many of those who have died hadpre-existing medical conditions or were elderly, those withweakened immune systems.

HOW IS IT TRANSMITTED AND HOW CAN IT BE PREVENTED?

The coronavirus can be transmitted from person toperson, although it is not clear how easily that happens. Mostcases are in people who have been in Wuhan, familymembers of those infected, or medical workers.

Transmission is most likely through close contact with aninfected person via particles in the air from coughing orsneezing, or by someone touching an infected person or objectwith the virus on it and then touching their mouth, nose oreyes.

In order to reduce the likelihood of transmission, the WHOrecommends that people frequently wash their hands, cover theirmouth and nose when sneezing or coughing, and avoid closecontact with those who are sick.

The U.S. Centers for Disease Control and Prevention saysthose who develop symptoms such as coughing and fever who havebeen in China in the last 14 days should call ahead to ahealthcare professional to establish if they need to be tested.

There is no vaccine.

WHERE HAS IT SPREAD?

The vast majority of the almost 10,000 cases identified have been in China, mostly in and around Wuhan. Theother countries with confirmed cases include Australia,Britain, Cambodia, Canada, France, Germany, India, Japan, Malaysia, Nepal, Sri Lanka, Singapore, Thailand, South Korea, the UAE, the United States, and Vietnam.

The WHO is looking closely at cases of person-to-persontransmission outside of Wuhan, which would suggest that it mayhave the potential to spread further. The WHO says there have been at least eight cases of human-to-human transmission in four countries outside China: the United States, Germany, Japan and Vietnam. Thailand has also reported a case of human-to-human transmission.

WHAT ARE AUTHORITIES DOING?

The Chinese government has put Wuhan into virtual quarantine to try to stop the spread of the virus. A number of foreigngovernments, including the United States, have advised against travel to China and have begun flying their citizens out of Wuhan.

The WHO has not recommended curbs on travel or trade with China.

IS THIS LIKE SARS?

The new virus is a strain of coronavirus, like SARS, whichkilled nearly 800 people globally in 2002 and 2003.

Unlike SARS, which also originated in China, it is believedthe new virus can spread during the incubation period of one to14 days, possibly before an infected person is showing symptoms.

The new virus does not appear to be as deadly as SARS, but there have been more cases overall.

(Editing by Robert Birsel)