PHNOM PENH, Feb. 12 (Xinhua) -- A 16-year-old boy from northeastern Cambodia's Kratie province has been confirmed for H5N1 human avian influenza, bringing the number of the cases to four so far this year, the Ministry of Health said in a statement on Monday.
"Laboratory results from the National Institute of Public Health showed on Sunday that the boy was positive for H5N1 virus," the ministry said.
"The patient has no symptom of respiratory illness and is the brother of a nine-year-old boy, who died of the virus on Feb. 8," the ministry added.
A team of health experts is looking into the source of the infection and is examining any suspected cases.
H5N1 influenza is a flu that normally spreads between sick poultry, but it can sometimes spread from poultry to humans, and its symptoms include fever, cough, runny nose, and severe respiratory illness.
The ministry said bird flu still poses threat to people's health, especially children, calling on people not to eat ill or dead poultry.
From 2003 to date, there were 66 cases of human infection with H5N1 influenza, including 42 deaths in the Southeast Asian country, according to the ministry. ■