(Reuters) - An outbreak of a new coronavirus that began in the central Chinese city of Wuhan has killed 25 people and infected more than 800 globally.
The virus has caused alarm because it is still too early to know just how dangerous it is and how easily it spreads between people. And because it is new, humans have not been able to build any immunity to it.
Here is what we know so far:
**There were 830 confirmed cases and 25 people had died in China, the National Health Commission said.
**The previously unknown strain is believed to have emerged late last year from illegally traded wildlife at an animal market in Wuhan.
**Thailand has four cases, Singapore three, Japan, Vietnam and South Korea with two apiece, and Taiwan and the United States one each.
**The World Health Organization said that while the outbreak was an emergency for China, it was not yet a global health emergency.
**Symptoms include fever, cough and difficulty breathing.
**China says the virus is mutating and can be transmitted through human contact.
**Those most affected are older people and those with underlying health conditions.
**Three research teams are to start work on developing potential vaccines, the Coalition for Epidemic Preparedness Innovations said. The plan is to have at least one potential vaccine in clinical trials by June.
**Preliminary research suggests the virus was passed to humans from snakes, but Chinese government medical adviser Zhong Nanshan has also identified badgers and rats as possible sources.
**Wuhan, a city of 11 million people, is under severe travel restrictions, with urban transport shut and outgoing flights suspended.
**Nearby Huanggang, a city of 7 million people, is suspending public transport and closing public venues, including movie theatres and internet cafes.
**Beijing closed tourist access to the Forbidden City and cancelled large gatherings, including two Lunar New Year temple fairs.
**Walt Disney Co's Shanghai Disney Resort will be closed from Saturday to help prevent the spread of a flu-like virus.
**Airports around the world have stepped up screening of passengers who have travelled to China.
**China's central bank said on Friday it would temporarily raise the upper limit on small bank batch payments to 500 million yuan ($72.42 million) from Friday until Jan. 30, to ease fund transfers amid the outbreak.
**Asian shares held their ground on Friday after the WHO did not declare a global emergency.
**Some experts believe the new virus is not as dangerous as the 2002-03 Severe Acute Respiratory Syndrome (SARS) that killed nearly 800 people, and Middle East Respiratory Syndrome (MERS), which has killed more than 700 people since 2012.
(Writing by Se Young Lee in Beijing; Editing by Stephen Coates)