Local tests have shown a 35-year-old man has died in Indonesia of the H5N1 strain of bird flu but the results have to be confirmed by a laboratory in Hong Kong, the Health Ministry said on Monday.

The ministry’s director general of disease control, I. Nyoman Kandun, said it was unclear if the man had contact with dead chickens. He died a few days ago, he said.

“We have sent the sample to Hong Kong for confirmation,” Kandun told Reuters by telephone. “We have not yet determined how he got the disease.”

Indonesia has had seven deaths from bird flu confirmed by the World Health Organization-affiliated laboratory. There have been four positive cases where patients survived.

The highly pathogenic H5N1 strain is endemic in poultry in parts of Asia, where it has killed more than 60 people.

Experts fear H5N1 could mutate into a form that passes easily among people, just like human influenza. If it does, millions could die because they would have no immunity.

Most human bird flu cases in Asia have been blamed on direct or indirect contact with infected chickens.