A new coronavirus, designated 2019-nCoV, was identified in Wuhan, the capital of China's Hubei, after people developed pneumonia without a clear cause, and for which existing treatments were not effective. The virus has shown evidence of human-to-human transmission, with the number of cases quickly climbing into the thousands by late January 2020 and several countries across Europe, North America and especially the Asia-Pacific reporting cases. Its incubation period (time from exposure to onset of symptoms) ranges from 2 to 14 days, but there is evidence that it may be contagious during this period and possibly also for several days after recovery. Symptoms include fever, coughing and breathing difficulties, and it can be fatal.
As of 3 February 2020, approximately 17,486 cases have been confirmed, including in every province-level division of China. The first confirmed death occurred on 9 January and since then, as of 3 February 2020, 362 deaths have been confirmed. A larger number of people may have been infected, but not detected (especially mild cases). The first local transmission of the virus outside China occurred in Vietnam from a father to his son, whereas the first local transmission not involving family occurred in Germany, on 22 January, when a German man contracted the disease from a Chinese business visitor at a meeting near Munich.The first death outside China was reported in the Philippines, where a 44-year-old Chinese male citizen confirmed to have contracted the coronavirus, Streptococcus pneumoniae and influenza B died on 1 February. In response, Chinese cities with a combined population of over 57 million people, comprising Wuhan and 15 other cities in the surrounding Hubei province, were placed on full or partial lockdown, involving the termination of all urban public transport and outward transport by train, air and long-distance buses. Many New Year events and tourist attractions have been closed to prevent mass gatherings, including the Forbidden City in Beijing and traditional temple fairs. Hong Kong also raised its infectious disease response level to the highest level and declared an emergency, closing its schools until March and cancelling its New Year celebrations. A number of countries have issued warnings against travel to Wuhan and Hubei. Travellers who have visited Mainland China have been asked to monitor their health for at least two weeks and contact their healthcare provider to report any symptoms of the virus. Anyone who suspects that they are carrying the virus is advised to wear a protective mask and seek medical advice by calling a doctor rather than directly visiting a clinic in person. The travel sector has been providing refunds and no-fee cancellations for reservations in China or by people from China. Airports and train stations have implemented temperature checks, health declarations and information signage in an attempt to identify carriers of the virus. The outbreak has been declared a Public Health Emergency of International Concern (PHEIC) by the World Health Organization (WHO), explaining that its decision was based on the possible effects that the pathogen could have if it spreads to countries with weaker healthcare infrastructures. The declaration makes it the sixth time that the measure has been invoked since the H1N1 pandemic in 2009.History
Wuhan is the capital of Hubei and is the seventh-largest city in China, with a population of more than 11 million people. It has been a major transport hub of the country throughout the ages, long known as the "Nine Provinces' Thoroughfare" (九省通衢), and the Wuhan Railway Hub is one of the four most important railway hubs in China. It is approximately 1,100 km (700 mi) south of Beijing, 800 km (500 mi) west of Shanghai, and 970 km (600 mi) north of Hong Kong. Direct flights from Wuhan connect it to major international cities in Europe and North America. In Wuhan, during December 2019, a cluster of cases displaying the symptoms of a "pneumonia of unknown cause" was linked to Huanan Seafood Wholesale Market, which had a thousand stalls selling fish, chickens, pheasants, bats, marmots, venomous snakes, spotted deer, and other wild animals (ye wei, bushmeat). The immediate hypothesis was that this was a novel coronavirus from an animal source (a zoonosis). Coronaviruses mainly circulate among other animals but have been known to evolve and infect humans as in the cases of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) together with four further coronaviruses that cause mild respiratory symptoms similar to the common cold. All coronaviruses known to infect humans have been shown to spread between people. Transmission of coronaviruses is primarily thought to occur among close contacts via respiratory droplets generated by sneezing and coughing.
Epidemiology
Chinese scientists were able to quickly isolate a strain of the coronavirus and publish the genetic sequence so that laboratories across the world could independently develop PCR tests to detect infection by the virus. The WHO had praised the Chinese for their swift efforts. 2019-nCoV's genome sequence is 75- to 80-percent identical to SARS-CoV, and more than 85-percent similar to several bat coronaviruses. Of the first 41 confirmed cases, two-thirds were found to have a link with the Huanan Seafood Wholesale Market, which also sold live animals. Of the first 41 confirmed 2019-nCoV cases, the earliest reported symptoms occurred 1 December 2019, in a person who did not have any exposure to the market or to the remaining 40 affected people. As the number of cases have increased, the significance of the market lessened. On 17 January, an Imperial College group in the United Kingdom published a report that there had been 1,723 cases (95% confidence interval, 427–4,471) with onset of symptoms by 12 January. This was based on the pattern of the initial spread to Thailand and Japan. They also concluded that "self-sustaining human-to-human transmission should not be ruled out", which has since been confirmed. As further cases came to light, they later recalculated that "4,000 cases of 2019-nCoV in Wuhan City had onset of symptoms by 18 January 2020". A Hong Kong University group has reached a similar conclusion as the earlier study, with additional detail on transport within China. On 20 January, China reported a sharp rise in cases with nearly 140 new patients, including two people in Beijing and one in Shenzhen.[64] On 25 January, the number of laboratory-confirmed cases stood at 2,062, including 2,016 in Mainland China, seven in Thailand, six in Hong Kong, five in Macau, five in Australia, four in Malaysia, four in Singapore, three in France, three in Japan, three in South Korea, three in Taiwan, three in the United States, two in Vietnam, one in Nepal, and one in Sweden.
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