JAKARTA, Indonesia (AP) — A 4-year-old Indonesian boy has died from bird flu, bringing the death toll to 160 in the country hardest-hit by the deadly virus, a health official said Tuesday.

While the H5N1 bird flu virus has killed relatively few people, scientists have been closely monitoring it for its potential to mutate and affect humans worldwide.

The boy died Dec. 6 in Tangerang city, just west of Jakarta, the capital, said Health Ministry official Rita Kusriastuti. He developed symptoms of a cold and fever on Nov. 30 and was treated at a public health center before being hospitalized the same day he died.

Kusriastuti said the boy, from the West Java district of Bogor, was believed to have been infected with the H5N1 virus after having direct contact with dead fowl around his house.

Bird flu has killed at least 360 people worldwide since 2003. It remains hard for people to catch, but experts fear it could mutate into a more deadly form that spreads easily from person-to-person. So far, most human cases have been linked to contact with infected poultry.

Last week, Kusriastuti said a form of the H5N1 virus not previously detected in Indonesia had killed hundreds of thousands of ducks on the main island of Java. The type of virus has been found circulating in a number of other countries and does not indicate any change that makes humans more susceptible.

The new form of the virus is believed to have entered Indonesia through imported ducks, but Kusriastuti said it's also possible it may have evolved on its own from existing strains.

Bird flu remains entrenched in Indonesia and elsewhere. It typically flares up during the winter months in affected countries with increases in poultry outbreaks and human cases.