The story of a traveling British businessman who appears to have passed the coronavirus to Britons in at least three countries has prompted concerns over a "super-spreader" who could play an outsize role in transmitting the infection.
A British national may have unwittingly spread the pneumonia-like virus to at least 11 people in the course of his travels from Singapore to France to Switzerland to England, according to public health authorities and accounts in the British media. Infected Britons in England, France and Spain probably caught the virus from him.
On Tuesday, the businessman was identified as Steve Walsh, a project management lead for Servomex, a gas analytics company. He attended a sales conference from January 18 to 22 at the Grand Hyatt hotel in Singapore, which is where he is thought to have contracted the virus.
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In a statement to The Washington Post sent via his employer, Walsh spoke of the other infected people.
"I would like to thank the NHS for their help and care - whilst I have fully recovered, my thoughts are with others who have contracted coronavirus," Walsh said, referring to Britain's National Health Service. He said that as soon as he discovered he had been exposed to a confirmed case, he contacted health authorities.
"I was advised to attend an isolated room at hospital, despite showing no symptoms, and subsequently self-isolated at home as instructed. When the diagnosis was confirmed I was sent to an isolation unit in hospital, where I remain, and, as a precaution, my family was also asked to isolate themselves," he said.
In a separate statement, Servomex said: "We are very pleased that Steve Walsh has made a full recovery. We continue to provide support to him and his family.
The company added: "We are working with Public Health authorities to ensure the welfare of our staff and communities and wish anyone with the virus a quick and full recovery."
As of Tuesday, China reported more than 1,000 deaths and 41,000 cases of the novel coronavirus, as the epidemic continued to worsen. Eight cases have been confirmed in Britain.
The coronavirus can spread quickly among humans, usually through close person-to-person contact and respiratory droplets. Authorities in Britain and beyond are scrambling to trace the businessman's tracks from the time he caught the virus to when he tested positive in Britain several days later. From Singapore, he reportedly stopped at a French ski resort, boarded a flight, dropped by a pub in his hometown and may have gone to a medical clinic. Authorities are getting in touch with those who may have come into close contact with him.
Researchers say that the incubation period for the virus can last up to 14 days.
After leaving Singapore, Walsh visited a chalet in Les Contamines-Montjoie, a ski resort in the French Alps. According to the French Health Ministry, five British citizens, including a 9-year-old, also stayed at the chalet and tested positive for the virus. The Guardian reported that French authorities shut two schools that the 9-year-old visited. Six other British nationals have been hospitalized for observation.
On Sunday, French health officials announced two new cases linked to the ski resort. "We learned that there were two other cases linked to this cluster, two adults - one who was diagnosed in the United Kingdom and the other who was diagnosed in Mallorca - linked to a stay in the apartment in Les Contamines-Montjoie," Jerome Salomon, a senior health official, said in a televised statement, Reuters reported.
On Monday, British officials announced that four more people in Britain tested positive for the coronavirus. Chris Whitty, chief medical officer for England, said that the "new cases are all known contacts of a previously confirmed U.K. case, and the virus was passed on in France."
After spending time at the chalet in the Alps, Walsh traveled to Geneva, where he caught a flight to London's Gatwick Airport on January 28. Nearly 200 people were on board the plane.
EasyJet, a discount airline, said that 183 passengers and six crew members were on the flight and that health authorities have contacted the passengers who were seated near the businessman.
"Although the risk to others on board the flight is very low, crew who operated the flight have been advised to monitor their health for a 14 day period since the flight in line with Public Health England advice," the airline said in a statement. "The original flight was 13 days ago and none are displaying any symptoms."
Walsh is from Hove, a town that neighbors Brighton. Together, the two places are known as Brighton and Hove.
On Monday, the BBC reported that a doctor's clinic in Brighton has been temporarily closed after one of its staff members tested positive for the coronavirus.
As of Monday afternoon, authorities in Britain had carried out 1,114 tests for the virus. Eight came back positive.
Adam Kucharski, an epidemiologist at the London School of Hygiene and Tropical Medicine, said it was "reassuring from a control point of view that these cases are linked." In Britain at the moment, he said, "we are not seeing five, 10 cases appearing that we've got no idea where they have come from."
On average, he said, those who are infected might pass the virus along to two people. Because the coronavirus is spread via droplets that do not travel far, it would not be unusual for someone infected traveling by plane not to pass it to many - or any - other passengers.