Vietnamese scientists will conduct human tests of a new vaccine against the deadly bird flu virus that has claimed 13 lives in recent weeks, state media reported on Friday.

The tests would follow successful results from initial tests on chicken and mice, which produced antibodies, the Tuoi Tre newspaper quoted the National Institute for Hygiene and Epidemiology as saying.

Doctor Hoang Thuy Nguyen, head of the group searching for a vaccine against the H5N1 virus that has killed 45 people altogether since arriving in Asia in late 2003, told Reuters early this month monkeys had also been tested.

On Friday, state newspapers said those results would be available in 10 days, Friday’s state media said.

Vietnam said this week it may slaughter poultry in its big cities in another tough action in the war against the avian virus that has spread to more than half its 64 provinces and cities since re-emerging in December.

However, the virus had caused no new poultry infections in poultry in nine of the affected provinces over the last three weeks, officials said.

They also noted that no new human infection had been reported in the past week and all bird flu patients had been discharged.

In early February, Chinese researchers said they had developed a bird flu vaccine for poultry and mammals that could fend off the deadly virus and help stop its spread, Chinese state media reported.

On Friday, an international team of doctors said the bird flu virus can produce a deadly encephalitis, diarrhoea and other symptoms that do not like the classic respiratory disease.

What the doctors fear most is that the virus could mingle with either human or pig influenza viruses, for instance by infecting a person who also had human flu, and acquire the ability to pass easily between people.

Such a new strain could kill tens of millions of people.