A 9-year-old boy from northwestern Battambang province died of Avian Influenza H5N1 at Sunday night, bringing the death toll to ten and the number of the cases to 16 so far this year, a World Health Organization official confirmed Monday.

"The boy, contracted with H5N1 human avian influenza, passed away late last night in the Jayavarman VII Hospital in Siem Reap province," Sonny Inbaraj Krishnan, media relations officer at the World Health Organization-Cambodia, said Monday.

The boy was admitted to the hospital with fever, cough, vomit, abdominal pain and dyspnea and was confirmed positive for human H5N1 avian influenza on Aug. 9.

"On hospital admission, he was initially in a stable condition. However, his condition deteriorated on Sunday and he passed away last night," he said.

"There were recent deaths among chickens and ducks in the village. The boy carried dead and sick ducks and chickens from a cage for food preparation by his sister before he became sick," he added.

Cambodia sees the worst outbreak of the virus this year since the disease was first identified in 2004. To date, the country has recorded 37 human cases of the virus, killing 29 people.

H5N1 influenza is a flu that normally spreads between sick poultry, but it can sometimes spread from poultry to humans, the World Health Organization said, adding that it is a very serious disease that requires hospitalization.