The World Health Organization (WHO) has declared a global health emergency over a new coronavirus that has killed at least 2,592 people following an outbreak in the central Chinese city of Wuhan.

A total of 77,150 cases of infection have been reported in mainland China, most of them in Hubei province, of which Wuhan is the capital.

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Deaths have also been confirmed in a number of Asia-Pacific nations, as well as Italy and Iran.

Here is what you need to know:

What is coronavirus?
According to the WHO, coronaviruses are a family of viruses that cause illnesses ranging from the common cold to more severe diseases such as severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS).

These viruses were originally transmitted between animals and people. SARS, for instance, was transmitted from civet cats to humans while MERS moved to humans from a type of camel.

Several known coronaviruses are circulating in animals that have not yet infected humans.

The name coronavirus comes from the Latin word corona, meaning crown or halo. Under an electron microscope, the image of the virus looks like a solar corona.

The novel coronavirus, identified by Chinese authorities on January 7 and since named COVID-19, is a new strain that had not been previously identified in humans. Little is known about it, although human-to-human transmission has been confirmed.

What are the symptoms?
According to the WHO, signs of infection include fever, cough, shortness of breath and breathing difficulties.

In more severe cases, it can lead to pneumonia, multiple organ failure and even death.

Current estimates of the incubation period – the amount of time between infection and the onset of symptoms – range from one to 14 days. Most infected people show symptoms within five to six days.

However, infected patients can also be asymptomatic, meaning they do not display any symptoms despite having the virus in their systems.

Read more on what the coronavirus does to your body if you catch it here.

Coronavirus
How deadly is it?
With more than 2,592 recorded deaths, the number of fatalities from this new coronavirus has surpassed the toll of the 2002-2003 SARS outbreak, which also originated in China.

SARS killed about 9 percent of those it infected – nearly 800 people worldwide and more than 300 in China alone. MERS, which did not spread as widely, was more deadly, killing one-third of those it infected.

While the new coronavirus is more widespread in China than SARS in terms of case numbers, the mortality rate remains considerably lower at approximately 2 percent, according to the WHO.

Where have cases been reported?
Most cases and deaths have been reported in China – the vast majority in Hubei province.

Deaths have also been confirmed in Hong Kong, the Philippines, Japan, France, Taiwan, South Korea, Italy and Iran.

The virus has spread to many countries in the Asia-Pacific region as well as in Europe, North America, the Middle East and Africa. The majority of cases outside China are among people who recently travelled to the country, however instances of human-to-human transmission have been recorded in several countries and questions have been raised about cases with no apparent link to China.

Read more about which countries have confirmed cases here.

What is being done to stop it from spreading?
Scientists around the globe are racing to develop a vaccine but have warned that one is unlikely to be available for mass distribution before 2021.

Meanwhile, Chinese authorities have effectively sealed off Wuhan and placed restrictions on travel to and from several other cities, affecting some 60 million people.

Many international airlines have cancelled flights to China. Some countries have banned Chinese nationals from entering their territories and several more have evacuated their citizens from Wuhan.

Where did the virus originate?
Chinese health authorities are still trying to determine the origin of the virus, which they say likely came from a seafood market in Wuhan where wildlife was also traded illegally.

On February 7, Chinese researchers said the virus could have spread from an infected animal species to humans through illegally-trafficked pangolins, which are prized in Asia for food and medicine.

Scientists have pointed to either bats or snakes as the source of the virus.

CARD: Coronavirus timeline
Is this a global emergency?
The outbreak now constitutes a global health emergency, the WHO said on January 30.

The decision to sound the top-level alarm was made after the first cases of human-to-human transmission outside China were confirmed.

The international health alert is a call to countries around the world to coordinate their response under the guidance of the United Nations health agency.

There have been five global health emergencies since 2005 when the declaration was formalised: swine flu in 2009, polio in 2014, Ebola in 2014, Zika in 2016 and Ebola again in 2019.