Coronavirus: All you need to know about symptoms and risks

The World Health Organization (WHO) has declared a global health emergency over a new coronavirus that has killed at least 361 people in China following an outbreak in the central city of Wuhan, forcing a government lockdown in almost 20 cities that, in effect, has quarantined an estimated 56 million people. More than 17,300 cases have been reported worldwide, most of them in China's Hubei province. A man from Wuhan also died in the Philippines on February 2, becoming the first fatality outside of China. More: Over a thousand 'likely' infected by Wuhan virus in China: Study Asia taking no chances with new China virus as WHO meeting looms China reports first death from mysterious outbreak in Wuhan The infection is now more widespread than the 2002-2003 severe acute respiratory syndrome (SARS) outbreak, which also originated in China, in terms of affected people but not deaths. Here is what you need to know: What is coronavirus? According to the World Health Organization (WHO), coronaviruses are a family of viruses that cause illness ranging from the common cold to more severe diseases such as SARS and Middle East respiratory syndrome (MERS). These viruses were originally transmitted between animals and people. SARS, for instance, was believed to have been transmitted from civet cats to humans while MERS travelled from a type of camel to humans. 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 is reminiscent of a solar corona. A novel coronavirus, identified by Chinese authorities on January 7 and named 2019-nCoV, 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, severe acute respiratory syndrome, kidney failure and even death. The incubation period of the coronavirus remains unknown. Some sources say it could be between 10 and 14 days. Coronavirus How deadly is it? Some experts say it may not be as deadly as other types of coronavirus such as SARS, which killed nearly 800 people worldwide, more than 300 in China alone - during a 2002-03 outbreak that also originated in China. MERS, which did not spread as widely, was more deadly, killing one-third of those it infected. In China, however, the infection is more widespread than SARS in terms of case numbers. Where have cases been reported? Most cases and deaths have been reported in China - the vast majority in Hubei Province. So far, the Philippines is the only country that has reported a fatality from the new virus outside of mainland China. The virus has spread to many Asian countries, as well as Australia, Europe, North America and the Middle East. Nearly all of the dozens of cases outside China are among people who recently travelled there. Read more about which countries have confirmed cases here. What is being done to stop it from spreading? Scientists are working on a vaccine but have warned one is unlikely to be available for mass distribution before 2021. Chinese authorities have effectively sealed off Wuhan, and have placed restrictions on travel to and from several other cities, affecting some 56 million people. The move was meant to "resolutely contain the momentum of the epidemic spreading" and protect lives, the central city's special command centre against the virus said, according to state broadcaster CCTV. Scores of airlines have cancelled flights to China, while some countries have banned Chinese nationals from entering and 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. The WHO also says an animal source appears most likely to be the primary source of the outbreak. On February 2, officials in Hubei said the virus had a 96 percent concordance with an already-known bat-borne coronavirus. Chinese scientists previously mentioned snakes as a possible source. Is this a global emergency? The outbreak constitutes a global health emergency, the WHO has said. 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 on 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. SOURCE: AL JAZEERA AND NEWS AGENCIES