Blood samples from two Indonesians hospitalised in Jakarta will be tested for the bird flu virus even though initial results showed both have typhoid, health officials said on Monday.

The two men, including a news photographer who had recently photographed chicken farms, are under close observation following the recent deaths of three members of a family from the virus, officials said. The samples would be sent to Hong Kong, they said.

Both men have been treated at a hospital in North Jakarta and are suffering from high fever and flu symptoms.

“The temporary diagnosis is typhoid. We have sent specimens to the WHO this morning for further tests,” said Evi Zelvino, a spokeswoman at the Jakarta health agency, referring to the World Health Organisation.

The WHO’s spokeswoman in Indonesia, Sari Setiogi, said they planned to send the samples to a laboratory in Hong Kong for testing and results should be known in 7-10 days.

Health experts are still puzzled how the country’s first victims - a father and his two young daughters - contracted the H5N1 virus this month in the world’s fourth-most populous country.

Avian influenza, which arrived in Asia in late 2003, has so far killed more than 50 people in the region including Vietnam, Thailand and Cambodia.

Zelvino also said an investigation would be carried out on a Malaysian national who died earlier this month. Doctors have said the Malaysian died from typhoid, although local media have speculated about the cause of his death.

In a sprawling archipelago dotted with small farms, and where even many urban families keep chickens, pinpointing the source of the bird flu virus is difficult.

On Sunday, officials slaughtered a number of pigs and fowl infected by bird flu near where the three victims of the virus lived, but the cull was lower than initially planned partly to protect the local economy.

In Indonesia, the virus has spread to 21 provinces out of 33 over the past two years, killing more than 9.5 million fowl.