China is investigating the possibility of human-to-human transmission of a new strain of bird flu that has killed 17 people and is examining “family clusters” of people infected with the virus, a top health official was quoted as saying yesterday.
Authorities have slaughtered thousands of birds and closed some live poultry markets to slow the rate of human infection. But many aspects of this new variety of bird flu remain a mystery, particularly whether the H7N9 strain is being transmitted between people.
China has warned that the number of infections, 82 so far, could rise. Most of the cases and 11 of the deaths have been in the commercial capital Shanghai.
Feng Zijian, director of the health emergency centre at the Chinese Centre for Disease Control and Prevention, told reporters that “we are paying close attention to these cases of family clusters”.
“(We) are still analysing in-depth to see which has the greatest possibility - did it occur first from avian-to-human transmission, and then a human-to-human infection, whether they had a common history of exposure, were exposed to infected objects or whether it was caused by the environment,” Feng said.
His comments were reported in a statement posted on the website of the National Health and Family Planning Commission.
One of the families that China is studying is made up of two brothers and their father who died of the virus, Feng said.
“This family cluster case still doesn’t change our understanding of the characteristics of the disease in general – that it is transmitted from birds to people and there’s no evidence of human-to-human transmission,” he added.
Efforts to determine the nature of the H7N9 virus are also hampered by a lack of accurate information from the victims on whether they have had contact with poultry.
The World Health Organisation (WHO) said on Wednesday that a number of people who have tested positive for the new strain appear to have had no contact with poultry.
The WHO had previously reported two suspected “family clusters”, but the first turned out to be a false alarm and the second was inconclusive.