Pakistan International Airlines (PIA) on Thursday announced that — as a precautionary measure — prospective passengers on its flights will be pre-screened for coronavirus at the Beijing Airport.

The respiratory virus has claimed 17 lives since emerging from a seafood and animal market in Wuhan, infected hundreds of other people nationwide and been detected as far away as the United States.

Animals are suspected to be the primary source of the coronavirus outbreak, with Chinese health officials saying the virus originated from the market where wild animals were illegally sold. Studies published this week suggest that the virus may have originated in bats or snakes.

The coronavirus has caused alarm because of its similarity to SARS (Severe Acute Respiratory Syndrome), which killed nearly 650 people across mainland China and Hong Kong in 2002-2003. Like SARS, it can be passed among people through the respiratory tract. The first case of the new virus was confirmed on December 31, 2019.

According to a PIA spokesperson, necessary instructions regarding the screening of passengers have been passed to the the national carrier's station management and operating crew in China.

Meanwhile, the airline officials have contacted the Ministry of National Health Services in Pakistan to also take necessary screening measures upon arrival of flights from Beijing.

Thermal scanners have been installed at four major airports within Pakistan as well. The scanners — installed at airports in Karachi, Lahore, Islamabad and Peshawar — are intended to scan passengers arriving at international terminals.

Passengers are facing similar screening measures at airports around the world.

The National Disaster Management Authority (NDMA) also tweeted on the matter and said that the authority's chairman is vigilant about the spread of coronavirus across Asia.

"NDMA in collaboration with Army Medical Corps, Ministry of Health & relevant stakeholders initiated precautionary measures to keep Pakistan safe from the threat," the tweet further said.

Factbox

Here is what we know so far about the outbreak of the virus:

• Chinese state television reported on Thursday there were 634 cases in China. Authorities have confirmed 17 deaths.
• The previously unknown strain is believed to have emerged late last year from illegally traded wildlife at an animal market in Wuhan.
• Thailand has reported four cases, and South Korea, Japan, Taiwan and the United States one each. Patients in these cases were either residents of Wuhan or recent visitors to the city.
• Singapore confirmed its first case on Thursday - a Chinese resident of Wuhan; an Indian nurse working in Saudi Arabia was confirmed infected; two Chinese citizens in Vietnam have tested positive.
• Symptoms include fever, cough and difficulty breathing.
• China says the virus is mutating. It says there is evidence of respiratory transmission.
• 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 on lockdown, with urban transport shut and outgoing flights suspended.
• Nearby Huanggang, a city of 7 million people, is suspending public transport and closing 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.
• Airports around the world have stepped up screening of passengers.
• The World Health Organisation was to decide on Thursday whether to declare the outbreak a global health emergency, which would step up the international response.
• World shares fell on Thursday, led by the biggest decline in Chinese stocks in more than eight months, as concern mounted about the spread of the virus.

Indian nurse in Saudi Arabia 'found infected'

An Indian nurse working in Saudi Arabia has tested positive for the coronavirus, the Indian foreign ministry said on Thursday.

Indian media reports said that the nurse may have contracted the virus while caring for a colleague from the Philippines who had tested positive.

“About 100 Indian nurses... working at Al-Hayat hospital have been tested and none except one nurse was found infected by Corona virus,” said minister of state for foreign affairs, V. Muraleedharan.

“Affected nurse is being treated at Aseer National Hospital and is recovering well,” he tweeted.

Muraleedharan confirmed to AFP that it was the same respiratory virus that has claimed 17 lives since emerging in Wuhan, infecting more than 570 people nationwide.

The 17 people who died in China were aged between 48 and 89, and had pre-existing health conditions, Chinese health authorities said on Thursday.

The virus has since been detected in Japan, Hong Kong, Macau, South Korea, Taiwan, Thailand, Vietnam, Singapore and the United States.

Meanwhile, the Saudi Centre For Disease Prevention And Control tweeted on Thursday that there were “no cases of the novel coronavirus(2019-nCoV) in Saudi Arabia so far.”

Saudi Arabia has started screening passengers arriving from China and has taken other preventive measures following the outbreak of the new coronavirus in China, the kingdom's health ministry had said on Wednesday.

China locks down two cities to curb virus outbreak

China locked down two major cities in a province at the centre of a deadly virus outbreak on Thursday, banning planes and trains from leaving in an unprecedented move aimed at containing the disease.

Residents in Wuhan, a major port city in central Hubei province with a population of 11 million people, were told Thursday not to leave "without a special reason", and the order was backed by a transport shutdown.

Trains and planes out of Wuhan were indefinitely suspended, tollways on roads out of the city were closed, leading to fear and panic for those who were trapped.

Hours later, authorities in neighbouring Huanggang announced that public transport and train services would be suspended at midnight, while people were told to not leave the city of 7.5 million.

All of Huanggang's cinemas, internet cafes, and the central market will close.

A third city, 1.1 million-population Ezhou, announced the train station had been temporarily closed earlier in the day.

WHO holds off decision on declaring a global health emergency

The World Health Organisation on Wednesday delayed a decision on whether to declare a global health emergency — a rare instrument used only for the worst outbreaks.

The emergency committee was supposed to meet again on Thursday, after its chair, Didier Houssin, said the experts were split over declaring a public health emergency.

WHO chief Tedros Adhanom Ghebreyesus said "more information" was needed but he also praised China's "very, very strong measures" that will help control the epidemic and "minimise the chances of this outbreak spreading internationally".

The WHO has confirmed that the virus can be passed between people, at least those in close contact. Chinese health officials warned it could mutate and spread further.

"There are many unknowns to address in this event including clinical severity and the true extent and nature of disease transmission," said Michael Ryan, head of the WHO's health emergencies programme.

The WHO chief, however, indicated the situation was not escalating out of control, saying there was "stability" for the moment. He also praised China's openness about the outbreak as "commendable".

Chinese authorities on Thursday reported dozens of new infections, bringing the confirmed total to 571. About 5,000 people remain under medical observation.

But scientists at the Imperial College in London estimate that 4,000 people have been infected in Wuhan.

Countries have intensified efforts to stop the spread of the pathogen — known by its technical name 2019 Novel Coronavirus (2019-nCoV).