Indonesian heath officials have just confirmed on Saturday that a 31-year-old man from Sumatra Island who died last week was infected with bird flu, raising the toll in the worst-hit nation to 91.

Deaths from the H5N1 virus have been steadily rising in archipelagic Indonesia where the virus is now endemic across 31 of its 33 provinces. The latest casualty was the second this month.

Two tests for the H5N1 virus must be returned positive before someone is confirmed as dying of avian flu here.

Nurdin, from the ministry's bird flu information centre, said that the latest victim died Tuesday in Pekanbaru shortly after arriving at its main hospital. He had fallen sick on October 31 and been admitted to a local hospital three days later.

Nurdin added that it was unclear whether the man had come into contact with poultry, the usual method of transmission of the disease to humans. Many Indonesians keep chickens or ducks in their backyards.

Azizman Daad from the state general hospital in the province told AFP that animal health teams from the Agriculture Ministry visited the area this week but didn't find any sick or dead chickens.

However, he said that an eight month baby living less than one kilometer away was suspected of bird flu and was now under treatment in the hospital, after the inspectors found bird nests.