Another victim of bird flu outbreak.
Tests for the boy, whose sister also died from bird flu, came back positive from a WHO-sanctioned laboratory in Hong Kong, Nyoman Kandun said.
Both died on May 23 in the city of Bandung, becoming the seventh case of family members, or clusters, hit by the disease in Indonesia, he said.
The laboratory also confirmed that a 14-year-old girl from Solok, West Sumatra, had been hit by the virus, Kandun said. Indonesia's total number of confirmed cases now is 50, of which 37 were fatal, he said.
Worldwide, bird flu has now killed at least 125 people since it began ravaging Asian poultry stocks in late 2003.
Kandun said all of the victims in the seven clusters were blood relatives, not spouses or in-laws, supporting an unproved theory that some people may have a genetic susceptibility to bird flu.
The two most recent siblings had a history of contact with dead birds, Kandun said.
A day after they died, animal health officials in the province found four chickens with the virus and culled up to 500 poultry within one kilometre of the victims' house.
Neighbours also reported that a number of chickens had suddenly died days before the victims were hospitalised.
Experts are puzzled why six of seven Indonesians from a family in a Sumatra village died from the H5N1 virus. An eighth was buried before tests were done.
There were no links to sick birds.