Health officials have revealed that three members of the same family were among the 41 people that contracted the newly identified coronavirus in the central China city of Wuhan, adding that they have neither confirmed nor ruled out the possibility of human-to-human transmission.
The three men – a father, his son and a cousin – lived together and ran a seafood stall at the Huanan Seafood Wholesale Market, which is widely thought to have been where the pneumonia outbreak started, Wuhan officials told visiting health experts from Hong Kong.
In an update released early on Wednesday, the officials said also that a husband and wife were among those affected. But while the husband worked at the seafood market as a trader, his wife said she had never even visited it.
Dr Chuang Shuk-kwan, one of the Hong Kong experts, said she was told there was no definitive evidence of human-to-human transmission and that no health care workers had been infected.
While the possibility of “limited” human-to-human transmission could not be ruled out, the risk of sustained human-to-human transmission was low, she said.
“The three men fell ill around the same time. As such, perhaps, they were not classified as human-to-human transmission cases within a family,” Chuang said.
She said the visiting experts had two meetings with local officials but did not visit the market.
According to health professionals, “limited” human-to-human transmission may occur under certain circumstances such as close contact between an infected person and an unprotected carer. However, limited transmission under such restricted circumstances does not mean that the virus spreads easily among humans.
Health authorities in Wuhan became aware of the coronavirus outbreak last month after several people – mostly vendors, suppliers and frequent visitors to the market – fell ill with pneumonia.
One person has since died from the disease.
As well as the infections in Wuhan, 76 suspected cases had been reported in Hong Kong as of Wednesday, of which 66 were later given the all-clear and discharged from hospital.
Meanwhile, a 61-year-old tourist from Wuhan is being treated at a hospital in Nonthaburi, to the north of Bangkok, after testing positive for the new strain on her arrival in Thailand.
The World Health Organisation (WHO) said in a tweet on Wednesday morning that the woman was a frequent visitor to a fresh market in Wuhan, though not specifically the one at the centre of the outbreak.
“The patient reported a history of visiting a local fresh market in Wuhan on a regular basis prior to the onset of illness; however, she did not report visiting the Huanan South China Seafood Market from where most of the novel #coronavirus (2019-nCoV) cases were detected,” it said, using the official name of the newly identified virus.
Professor David Hui Shu-cheong, an expert on respiratory medicine at the Chinese University of Hong Kong, said that on the basis of the woman’s statement, authorities in Wuhan should investigate the market she said she had visited and check any others that sold game meat.
Officials in Wuhan said earlier that several people who had been in close contact with the tourist had been put under medical observation, but none had shown any abnormal symptoms.
“Existing investigation found no clear human-to-human evidence,” the Wuhan Health Commission said in a statement. “The possibility of limited human-to-human transmission cannot be ruled out, but the risk of continued human-to-human transmission is low.”
Despite the absence of clear evidence of human-to-human transmission and lack of infections reported among health care workers, the WHO called for further investigation into possible modes of transmission, because of the dangers of the potential human-to-human spread of respiratory illnesses.
“It can be difficult to determine if they are ill due to exposure to a common source of infection, or because one person passed the illness to the other,” it said in a statement.
Wuhan authorities have collected environment samples from the seafood market, which has been closed since January 1, and found some that tested positive for the coronavirus.
Preliminary investigations in other markets in the city had found no clues to the source of the outbreak, the health commission said.
Chuang said she was told that some of the samples – taken from table tops, the floor and vendors’ gloves, among other places – had tested positive for the coronavirus.
“I understand they have also collected samples from other areas of the market but so far only those collected from the seafood section tested positive.”
Asked if there was any evidence that the virus could have come from an animal, Chuang said: “I understand [local experts] may also have started trying to trace the source of the virus to animals.
“The experts are of the view that the chance of seafood being the source of the virus [found in the environmental samples] is not high. Thus, the direction would be tracing it to some other animal,” she said.
“The Huanan Seafood Wholesale Market mainly sells seafood and poultry. We were also given to understand that animals such as bamboo rats, snakes, badgers and hedgehogs were also available there.”
Most of the people diagnosed were middle-aged or elderly and male, the Wuhan health authority said. Six of the 41 were still being treated as severe cases, while seven had been cured and discharged.
More than 760 people who had been in close contact with those patients had been put under medical investigation, with 187 having been removed from quarantine by Tuesday after showing no symptoms for two weeks, the authorities said.
As a major transport hub with a population of 11 million people, the pneumonia outbreak in Wuhan has raised concerns the disease could spread to other cities during the Lunar New Year travel season, which is now under way.
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This article China coronavirus outbreak: five members of two families among 41 people infected in Wuhan first appeared on South China Morning Post