The results of local laboratory tests on an Indonesian father and his son hospitalized in Jakarta with avian influenza symptoms showed that they were not contracted by the H5N1 virus, a senior official of Indonesian Health Ministry said here on Friday.

Hariadi Wibisono told Xinhua by telephone that the blood samples would still be sent to a laboratory in China's Hong Kong for confirmation.

"The local test result is negative, and the samples are sent to Hong Kong," he said.

The case of the father and son prompted the Indonesian Health Minister Siti Supari Fadillah on Thursday to say that the disease could possibly be spreading from human to human in Indonesia.

But the World Health Organization's Technical Officer Steven Bjorge said that the organization still did not have evidence that the virus was mutating into a form that passed easily among humans.

"Until now we don't have a strong evident on that," he said.

More than five Indonesians have died due to the virus or with bird flu-like symptoms in the last several months.

Source: Xinhua