International airports are stepping up screening for passengers exhibiting symptoms possibly connected with the previously unknown corona virus that has infected nearly 200 people in China and caused two deaths there. Three major US airports – San Francisco International Airport (SFO), Los Angeles International Airport (LAX) and John F Kennedy International Airport in New York (JFK) — have announced they will screen travelers arriving from Wuhan. Passengers will be examined for symptoms of the pneumonia-like virus, the Centers for Disease Control and Prevention (CDC) said, with an additional 100 health workers deployed at the airports. Singapore and Thailand also have been screening air passengers from Wuhan. Investigations into this novel corona virus are ongoing and we are monitoring and responding to this evolving the situation, said Martin Cetron, the head of the CDC’s Division of Global Migration and Quarantine. Corona viruses were first identified in the 1960s, but we don’t know where they come from. They get their name from their crown-like shape. Sometimes, but not often, a corona virus can infect both animals and humans. A novel (new) corona virus is causing an outbreak in Wuhan City, Hubei Province, China. Cases have been exported to Thailand and Japan. No cases have been identified in the United States. Chinese health authorities have reported that patients have experienced fever, cough, difficulty breathing and pneumonia. CDC is responding to this emerging public health issue. Most corona viruses spread the same way other cold-causing viruses do, through infected people coughing and sneezing, by touching an infected person’s hands or face, or by touching things such as door knobs that infected people have touched. Almost everyone gets a corona virus infection at least once in their life, most likely as a young child. In the United States, corona viruses are more common in the fall and winter, but anyone can come down with a corona virus infection at any time. The number of people infected with a new virus in China tripled over the weekend, with the outbreak spreading from Wuhan to other major cities. There are now more than 200 cases, mostly in Wuhan, though the respiratory illness has also been detected in Beijing, Shanghai and Shenzhen. The WHO says entry screening offers little benefit while requiring considerable resources. It suggests anyone with respiratory illness should seek medical attention and share travel history with their health care provider. Number of cases in an outbreak of a new strain of corona virus in China is likely to have been grossly underestimated, according to a new study, which warns that human-to-human transmission of the mysterious virus may be possible. Authorities in China’s Wuhan city have confirmed 200 cases of the 2019 novel corona virus, which is in the same family as the deadly severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS), but so far appears to be less lethal. Two people have died, Wuhan authorities say. But a study, by Imperial College London, suggests that an estimated 1,723 people were likely to have been infected by January 12. Officials in China have linked the viral infections to a Wuhan seafood and wildlife market, which has been closed since January 1 to prevent further spread of the illness. Members of staff of the Wuhan Hygiene Emergency Response Team conduct searches on the closed Huanan Seafood Wholesale Market in Wuhan. Three travelers, two now in Thailand and one in Japan, who visited Wuhan but not the market have been infected with the virus, suggesting human-to-human transmission maybe possible and raising concerns about the virus’s further spread. South Korea, meanwhile, confirmed its first case on Monday. Officials there said a traveler arriving at Seoul’s Airport, who had been to Wuhan last week, tested positive for the virus and had been treated at a local hospital. This brings the number of countries with confirmed cases to four. The number in the study is only an estimate and is based on several assumptions, including the number of cases that have been exported to Thailand and Japan, the number of people using Wuhan International Airport and the time it has taken for the infection to incubate. Imperial College London’s Neil Ferguson, a disease outbreak scientist, said that many aspects of the Wuhan corona virus was “highly uncertain.” Viral samples have been taken from patients and analysed in the laboratory. Officials in China and the World Health Organisation has concluded that the infection is a Corona virus. China’s new SARS-like virus has spread to Japan but we still know very little about it. However, the detection of four cases outside China is worrying. We calculate, based on flight and population data, that there is only a one in 574 chance that a person infected in Wuhan would travel overseas before seeking medical care. This implies there might have been over 2,000 cases in Wuhan so far. There are many unknowns, meaning the uncertainty range around this estimate goes from 200 cases to over 4,000. But the magnitude of these numbers suggests that substantial human-to-human transmission cannot be ruled out. Heightened surveillance, prompt information sharing, and enhanced preparedness are recommended. While the new virus has not shown death rates like MERS and SARS, which infected more than 8,000 people and killed 774 in a pandemic that ripped through Asia in 2002 and 2003, so little is known about it that health authorities are calling for vigilance. Only two patients in the US have ever tested positive for MERS-CoV infection, both in May 2014. CDC continues to closely monitor the situation. Much remains to be understood about the new corona virus, which was first identified in China earlier this month. Not enough is known about 2019-nCoV to draw definitive conclusions about how it is transmitted, clinical features of the disease, or the extent to which it has spread. The source also remains unknown,” the World Health Organisation said. WHO announced Monday that it was convening an emergency meeting on Wednesday, Jan22, “to ascertain whether the outbreak constitutes a public health emergency of international concern, and what recommendations should be made to manage it.” The writer is a retired doctor of the Sindh Health Department