China has put millions of people in three cities on lockdown in an effort to contain a coronavirus outbreak that has killed 17 people and infected more than 630.
Health officials fear the number of infected will rise rapidly as hundreds of millions of Chinese people travel within China and abroad during the week-long Lunar New Year holidays, which begin on Saturday.
Airports worldwide have been screening passengers arriving from China. Thailand has confirmed four cases, while the United States, Singapore, Japan, South Korea and Taiwan have reported one each.
Sharing the full story, not just the headlines
The previously unknown virus strain is believed to have emerged late last year from illegally traded wildlife at an animal market in the central city of Wuhan.
The coronavirus family includes the common cold as well as viruses behind more serious illnesses, such as the Sars outbreak which killed around 800 people during in 2002-2003.
Medical staff transfer patients to Jin Yintan hospital in Wuhan. China has confirmed that the deadly Wuhan coronavirus virus can be transmitted between humans, with medical workers currently among the infected
Getty
Officials say the number of confirmed cases of the new and mysterious virus has risen sharply above 200
EPA
Passengers scanned by thermal imaging for body temperature as they go through health measures and procedures after they landed at Rome’s Fiumicino airport on a southern airlines flight from Wuhan
Aeroporto Di Roma/AFP via Getty
The new coronavirus appears to have its origins in a seafood market in the central Chinese city of Wuhan, a popular transport hub
AFP via Getty
Members of the Italian Red Cross putting on protective gear, getting ready to give health checks to passengers that landed at Rome’s Fiumicino airport on a southern airlines flight from Wuhan
Aeroporto Di Roma/AFP via Getty
A member of the Hong Kong government’s Civil Aid Service gestures at the entrance to the Lady MacLehose Holiday Village which is being used as one of two quarantine centres for people who have been in close proximity with suspected cases of a SARS-type virus. Hong Kong will turn two holiday camps, including a former military barracks, into quarantine zones for people who may have come into contact with carriers of the Wuhan virus, officials announced
AFP via Getty Images
Medical staff wearing protective suits at the Zhongnan hospital in Wuhan
STR/AFP via Getty
A Malaysia Health official checks passengers going through a thermal scanner upon their arrival at the Kuala Lumpur International Airport
EPA
China banned trains and planes from leaving the major city at the centre of a virus outbreak on January 23, seeking to seal off its 11 million people to contain the contagious disease that has claimed lives and spread to other countries
AFP via Getty
A passenger walks past a quarantine control station at Narita airport, Japan
EPA
Patients queue up to seek treatment in Wuhan Tongji Hospital Fever Clinic, in Wuhan
EPA
Quarantine workers spray disinfectant at Incheon International Airport, South Korea
EPA
A member of staff checks the temperature of a guest entering the casino of the New Orient Landmark hotel in Macau, after it reported its first case of the new SARS-like virus
AFP via Getty
Little is known about the new disease which, if confirmed, would be only the seventh coronavirus known to science that can infect humans
Getty
Members of the Three Gorges Medical Laboratory offering free masks to the public in Yichang, China
AFP via Getty
Gabriel Leung, right, chair professor of public health medicine at the Faculty of Medicine at the University of Hong Kong, speaks about the extent of the Wuhan coronavirus outbreak in China
AFP via Getty
Members of staff of the Wuhan Hygiene Emergency Response Team conducting searches on the closed Huanan Seafood Wholesale Market
AFP via Getty
The virus causes symptoms of viral pneumonia, and has already led to several deaths
EPA
A screen shows cancelled flights at Tianhe airport in Wuhan
AFP via Getty
Medical staff transfer patients to Jinyintan hospital
EPA
Health officials hand out information about the current coronavirus at Kuala Lumpur International Airport
AP
A store owner argues with security guards as he attempts to enter the closed Huanan wholesale seafood market
AFP via Getty
Workers producing facemasks at a factory in Handan, China’s northern Hebei province
AFP via Getty
Medical staff and security personnel stop patients’ family members from being too close to the Jinyintan hospital
Reuters
maya-goodfellowAn airport staff member uses a temperature gun to check people leaving Wuhan Tianhe International Airport
AP
A rescue worker walks past a notice about new coronavirus that has broken out in China
Reuters
Health officials wear face masks at an inspection site at the Kuala Lumpur International Airport in Sepang
AP
Medical staff members carry a patient into the Jinyintan hospital
AFP via Getty
A staff member checks body temperature of a child after a train from Wuhan arrived at Hangzhou Railway Station in Hangzhou
AFP via Getty Images
A quarantine station measures passenger body temperatures at Narita Airport
JIJI PRESS/AFP via Getty
Passengers walk past a notice displayed near a quarantine control station at Narita airport
EPA
Passengers walk past a poster alerting on coronavirus screening ahead upon their arrival at the Kuala Lumpur International Airport
EPA
An employee sprays disinfectant on a train, as a precaution against coronavirus, at Suseo Station in Seoul
EPA
Kazakh sanitary-epidemiological service worker uses a thermal scanner to detect travellers from China who may have symptoms possibly connected with the previously unknown coronavirus, at Almaty International Airport, Kazakhstan
Reuters
Pharmacist Liu Zhuzhen stands near a sign reading “face masks are sold out” at her pharmacy in Shanghai
AP
The Wuhan Medical Treatment Center,
EPA
A worker in a protective suit at the closed seafood market in Wuhan
Reuters
Passengers wear protective face masks at the departure hall of a high speed train station in Hong Kong
AP
A notice for passengers from Wuhan
Getty
A man wears a mask while riding on mobike past the closed Huanan Seafood Wholesale Market
Getty
Passengers walk past a thermal scanner upon their arrival at Narita airport
Getty
Medical staff transfer patients to Jinyintan hospital
EPA
Passengers wearing masks enter the Beijing West Railway Station
Reuters
Passengers wear protective face masks as they ride the subway in Hong Kong
AP
Medical staff transfer patients to Jin Yintan hospital in Wuhan. China has confirmed that the deadly Wuhan coronavirus virus can be transmitted between humans, with medical workers currently among the infected
Getty
Officials say the number of confirmed cases of the new and mysterious virus has risen sharply above 200
EPA
Passengers scanned by thermal imaging for body temperature as they go through health measures and procedures after they landed at Rome’s Fiumicino airport on a southern airlines flight from Wuhan
Aeroporto Di Roma/AFP via Getty
The new coronavirus appears to have its origins in a seafood market in the central Chinese city of Wuhan, a popular transport hub
AFP via Getty
Members of the Italian Red Cross putting on protective gear, getting ready to give health checks to passengers that landed at Rome’s Fiumicino airport on a southern airlines flight from Wuhan
Aeroporto Di Roma/AFP via Getty
A member of the Hong Kong government’s Civil Aid Service gestures at the entrance to the Lady MacLehose Holiday Village which is being used as one of two quarantine centres for people who have been in close proximity with suspected cases of a SARS-type virus. Hong Kong will turn two holiday camps, including a former military barracks, into quarantine zones for people who may have come into contact with carriers of the Wuhan virus, officials announced
AFP via Getty Images
Medical staff wearing protective suits at the Zhongnan hospital in Wuhan
STR/AFP via Getty
A Malaysia Health official checks passengers going through a thermal scanner upon their arrival at the Kuala Lumpur International Airport
EPA
China banned trains and planes from leaving the major city at the centre of a virus outbreak on January 23, seeking to seal off its 11 million people to contain the contagious disease that has claimed lives and spread to other countries
AFP via Getty
A passenger walks past a quarantine control station at Narita airport, Japan
EPA
Patients queue up to seek treatment in Wuhan Tongji Hospital Fever Clinic, in Wuhan
EPA
Quarantine workers spray disinfectant at Incheon International Airport, South Korea
EPA
A member of staff checks the temperature of a guest entering the casino of the New Orient Landmark hotel in Macau, after it reported its first case of the new SARS-like virus
AFP via Getty
Little is known about the new disease which, if confirmed, would be only the seventh coronavirus known to science that can infect humans
Getty
Members of the Three Gorges Medical Laboratory offering free masks to the public in Yichang, China
AFP via Getty
Gabriel Leung, right, chair professor of public health medicine at the Faculty of Medicine at the University of Hong Kong, speaks about the extent of the Wuhan coronavirus outbreak in China
AFP via Getty
Members of staff of the Wuhan Hygiene Emergency Response Team conducting searches on the closed Huanan Seafood Wholesale Market
AFP via Getty
The virus causes symptoms of viral pneumonia, and has already led to several deaths
EPA
A screen shows cancelled flights at Tianhe airport in Wuhan
AFP via Getty
Medical staff transfer patients to Jinyintan hospital
EPA
Health officials hand out information about the current coronavirus at Kuala Lumpur International Airport
AP
A store owner argues with security guards as he attempts to enter the closed Huanan wholesale seafood market
AFP via Getty
Workers producing facemasks at a factory in Handan, China’s northern Hebei province
AFP via Getty
Medical staff and security personnel stop patients’ family members from being too close to the Jinyintan hospital
Reuters
maya-goodfellowAn airport staff member uses a temperature gun to check people leaving Wuhan Tianhe International Airport
AP
A rescue worker walks past a notice about new coronavirus that has broken out in China
Reuters
Health officials wear face masks at an inspection site at the Kuala Lumpur International Airport in Sepang
AP
Medical staff members carry a patient into the Jinyintan hospital
AFP via Getty
A staff member checks body temperature of a child after a train from Wuhan arrived at Hangzhou Railway Station in Hangzhou
AFP via Getty Images
A quarantine station measures passenger body temperatures at Narita Airport
JIJI PRESS/AFP via Getty
Passengers walk past a notice displayed near a quarantine control station at Narita airport
EPA
Passengers walk past a poster alerting on coronavirus screening ahead upon their arrival at the Kuala Lumpur International Airport
EPA
An employee sprays disinfectant on a train, as a precaution against coronavirus, at Suseo Station in Seoul
EPA
Kazakh sanitary-epidemiological service worker uses a thermal scanner to detect travellers from China who may have symptoms possibly connected with the previously unknown coronavirus, at Almaty International Airport, Kazakhstan
Reuters
Pharmacist Liu Zhuzhen stands near a sign reading “face masks are sold out” at her pharmacy in Shanghai
AP
The Wuhan Medical Treatment Center,
EPA
A worker in a protective suit at the closed seafood market in Wuhan
Reuters
Passengers wear protective face masks at the departure hall of a high speed train station in Hong Kong
AP
A notice for passengers from Wuhan
Getty
A man wears a mask while riding on mobike past the closed Huanan Seafood Wholesale Market
Getty
Passengers walk past a thermal scanner upon their arrival at Narita airport
Getty
Medical staff transfer patients to Jinyintan hospital
EPA
Passengers wearing masks enter the Beijing West Railway Station
Reuters
Passengers wear protective face masks as they ride the subway in Hong Kong
AP
Here are some of the key features of coronaviruses:
They get their name from their appearance under a microscope, which reveals them to be spherical and covered with crown-like spikes.
The strain found in China has been dubbed a novel coronavirus, meaning it has not been previously identified.
Those infected with cornavirus have shown a wide range of symptoms, including fever, coughing, shortness of breath and breathing difficulties.
Severe cases have caused pneumonia, severe acute respiratory syndrome, kidney failure and death.
Screening in Chinese city of Wuhan at centre of coronavirus
Coronaviruses are transmitted between animals and humans, and can evolve into strains not previously identified in humans.
Preliminary research has suggested the Wuhan coronavirus may have made the jump to humans from snakes, but Chinese government medical experts have also suggested badgers and rats as possible sources.
Like other coronaviruses, it is being transmitted from person to person via droplets when an infected person coughs or sneezes.
It can also spread via contaminated surfaces, such as door handles or railings.
Like the viruses that cause Sars and Mers, the current virus is an RNA virus — meaning it has RNA rather than DNA as its genetic material — which allows it to blend with its host’s DNA and also means it can mutate rapidly.
Trump says US has coronavirus ‘completely under control’
Testing for the virus involves the use of a real-time polymerase chain reaction (RT-PCR), which identifies the viral RNA in a sample.
These could come from a throat swab, a cough sample, or a blood sample if the patient is very ill.
There is currently no vaccine for the virus.
The World Health Organisation (WHO) will decide on Thursday whether to declare the outbreak a global health emergency, which would ratchet up the international response.
Additional reporting by agencies