A ten-year-old boy died of bird flu on Saturday, bringing the death toll of the fatal disease to 13 in Cambodia so far this year, a World Health Organization (WHO) official said.

"We regret to announce that the boy passed away in Kantha Bopha Hospital this morning," said Sonny Inbaraj Krishnan, communication and media relations officer at the WHO office in Cambodia.

Only 11 out of the 24 cases this year survived.

The boy was confirmed positive for human H5N1 avian influenza on Thursday after he was admitted to the Kantha Bopha Hospital in Phnom Penh with fever, cough, sore throat, a distended abdomen and dyspnea.

A joint press statement from the Cambodian Health Ministry and the WHO office said the investigation found that a month before the boy fell ill, about 30 chickens had died suddenly in his village in southern Kampot province and the boy helped carry dead chickens for his brother who was preparing a meal from them.

H5N1 influenza usually spreads among poultry, but it can sometimes spread from poultry to human, according to the WHO.

To date, the country has reported 45 human cases of contracting the deadly virus, killing 32 people.