JAKARTA (Reuters) - A 3-year-old Indonesian boy from SouthJakarta has died from bird flu, taking the country's death tollfrom the virus to 105, a health ministry official said onMonday.

Nyoman Kandun, director general of communicable diseasecontrol at the ministry, said the boy died on Friday and twotests had confirmed he contracted the H5N1 virus.

"Most people in his neighborhood keep chicken in theirbackyard, so it was very likely that the boy had contact withchicken," Kandun told Reuters.

Indonesia has a poultry population of 1.2 billion a year,including 285 million chickens kept by families in theirbackyards.

Contact with sick fowl is the most common way ofcontracting bird flu, endemic in bird populations in most ofIndonesia.

There has been a sudden spike in bird flu cases inIndonesia since the start of the year. Some experts say theflare-up is caused by factors such as damp weather and poorsanitation during the rainy season.

Indonesia has the highest number of bird flu deaths in theworld.

Although bird flu remains an animal disease, experts fearthe H5N1 virus could mutate into a form easily passed fromhuman to human. Millions of people could die because they wouldhave no immunity to the new strain.

(Reporting by Mita Valina Liem; Editing by Sugita Katyal)