Hong Kong has reported its first case of the deadly new H7N9 bird flu strain, in what public health experts say is a worrying sign that the virus could be spreading from mainland China.
The government said a 36-year-old Indonesian maid had fallen ill after returning from a trip to the Chinese city of Shenzhen last month, where she was believed to have come into contact with live poultry.
Hong Kong officials have now issued a “serious” influenza pandemic response warning, raising the level from “alert”, and contacted the World Health Organisation (WHO).
Health Secretary Ko Wing-man said the maid had a history of travelling across the border to the mainland city to buy, slaughter and eat chickens. She is under close surveillance in hospital and was described as being in a critical condition.
Mr Ko said authorities had quarantined the family for whom she worked. There have been fears in the past that the H7N9 strain could transmit from human-to-human, and some people with whom the maid has had contact since returning to Hong Kong were reported to be suffering respiratory problems.
Dr Benjamin Cowling, a professor of public health at the University of Hong Kong, told the Wall Street Journal Live that the news was deeply concerning.
“We now know for sure the virus hasn’t gone anyway and there are concerns it could come back in larger numbers this winter,” he said.
The WHO said there have been 139 confirmed cases of people falling ill as a result of H7N9, with 45 of those victims dying as a result.
Comparing the strain with the more common H5N1 variety, Dr Cowling said: “The concern is that unlike H5N1, H7N9 is not highly pathogenic in chickens.
“With the former, if there is a case then the chickens die or there is clearly something wrong, but that is not the case with H7N9 – there is no way of telling whether the chickens are affected or not.”
H7N9 was first identified in April, when a series of deaths prompted officials to shut down meat markets and slaughter poultry in several mainland Chinese cities.
Those measures seemed to have slowed the spread of the disease, but the latest outbreak has led scientists to fear the virus will re-emerge in the winter, when influenza is most active.
Mr Ko said the Hong Kong government would step up its flu pandemic preparedness plan. Infectious diseases are a particular concern in the city, where the 2003 outbreak of Severe Acute Respiratory Syndrome, or Sars, killed about 299 people. Nearly 500 more deaths were reported in other countries.