Bird flu was found in a 4-year-old Beijing boy who has no symptoms of the infection, health authorities said, suggesting more people may be catching the H7N9 influenza virus than reported.
The first asymptomatic H7N9 case was discovered by health- care workers searching for possible cases, the Beijing Municipal Health Bureau said in a statement on its website today. The boy’s parents are poultry and fish sellers, and their neighbors across the street had bought chicken sold by the family of a 7- year-old girl whose H7N9 infection was reported two days ago.
The boy is under medical observation. The case suggests some H7N9 infections may be going unrecorded because of a lack of obvious symptoms. Almost all of the 64 people diagnosed with the virus so far have been extremely unwell, with complications extending to brain damage, multi-organ failure and muscle breakdown.
“With asymptomatic cases around, I think everything changes,” said Ian Mackay, an associate professor of clinical virology at the University of Queensland in Brisbane, in a telephone interview today.
“There has been a spike in pneumonia cases that have drawn the health officials’ attention, but the virus may have been going around as a normal cold.”
The boy’s infection was picked up as part of contact tracing -- a process whereby relatives, neighbors and others known to have been in contact with a confirmed case are screened for the virus. The boy was one of 24 people tested in connection with the 7-year-old girl’s infection.
Sick or Not?
“It’s great that the authorities are showing some evidence of prospective screening of contacts, not just asking people if they are sick or not,” Mackay said.
“It’s essential that lab testing of contacts is carried out as soon as possible to give us some information about the denominator: how many cases are positive for this virus, whether they’re symptomatic or not.”