"Laboratory results from the National Institute of Public Health showed on Saturday that the girl was positive for H5N1 virus," the statement said on Saturday midnight.
"Currently, the patient is in severe condition and is receiving intensive care from a team of doctors," Xinhua news agency reported, citing the statement.
The patient, who lives in Chantrea district's Chamkar Leav village, has the symptoms of fever, cough, sore throat, and dyspnea,
"According to queries, about four days before the girl fell ill, a total of nine chickens and ducks in the village and at her house had died. The patient's family cooked them for food, and the girl had direct contact with the dead poultry," the statement said.
Health authorities are looking into the source of the infection and are examining any suspected cases or people who have been in contact with the victim in order to prevent an outbreak in the community.
Among the nine human cases of H5N1 bird flu so far this year were eight children, one of whom died, and an adult. All patients reportedly had a history of exposure to sick or dead poultry prior to their illness.
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, particularly children, urging people not to eat ill or dead poultry.
From 2003 to date, there were 71 cases of human infection with H5N1 influenza, including 42 deaths in the Southeast Asian country, according to the ministry.