Bird flu is said to be spreading again in Vietnam - from the south to the central and northern parts of the country.

Since the beginning of this year, infected poultry have been found in the capital city of Hanoi. Six people were discovered with the disease, of which four have died, the New Scientist reported.

In the beginning of 2004, Vietnam suffered a massive outbreak of bird flu, which affected 31 people, 21 of whom died. The virus was declared under control in March after nearly one-fifth of its poultry was killed.

The virus re-surfaced in Dec 2004, with outbreaks in the southern Mekong delta.

But since then, there have been reports of infected ducks and chicken in the central province of Quang Nam, and in recent days in the northern province of Ha Nam and Hanoi.