Cambodia's Health Ministry and the World Health Organization announced Friday that the girl had a history of contact with poultry in her village in southeastern Takeo province, where there was evidence of recent deaths among poultry.
Only one of Cambodia's six victims this year of the virus, also called avian influenza, or H5N1, has survived the disease. The country reported three cases in 2012, all fatal.
WHO statistics issued Feb. 1 show Cambodia as the only country so far reporting human cases of the disease in 2013.
The U.N. agency says bird flu has killed 365 other people worldwide since surfacing in 2003. Most human cases have been linked to contact with infected poultry.