PHNOM PENH: Cambodia has reported three new human cases of bird flu, two of them fatal, in the first three weeks of this year.

The cases are among the first reported in 2013 for the virulent H5N1 virus, which the World Health Organization says has killed 360 other people worldwide since surfacing in 2003.

WHO and Cambodia's health ministry announced Friday that a 15-year-old girl in a village in southeastern Takeo province and a 35-year-old man in central Kampong Speu province died after being hospitalized with H5N1, better known as bird flu. An 8-month-old boy in the capital, Phnom Penh, was treated and survived.

The disease remains hard for people to catch, but experts fear it could mutate into a more deadly form that spreads easily from person to person.