A woman in southern Vietnam has died after contracting the bird flu virus, health authorities said Thursday, in the country's second human death from the virulent disease in less than a month.

Concerns about avian influenza have risen in the region with China, Cambodia and Indonesia all reporting deaths from the H5N1 virus this year.

Vietnam has culled thousands of birds in affected areas in a bid to contain bird flu outbreaks.

The 26-year-old woman from Soc Trang province in the Mekong delta died on January 28. Tests on the victim after she died confirmed she had contracted the H5N1 virus, the Hanoi-based Preventive Healthcare department said.

"The victim culled and ate sick chicken. There had also been sick and dead poultry around her residence," it said in a report.

On January 11, a duck farmer from the southern Mekong delta province of Hau Giang died from bird flu -- Vietnam's first human death from the disease since April 2010.

According to the World Health Organisation, Vietnam has recorded one of the highest numbers of fatalities from bird flu in southeast Asia, with at least 59 deaths since 2003.

The avian influenza virus has killed more than 330 people around the world, and scientists fear it could mutate into a form readily transmissible between humans, with the potential to cause millions of deaths.

Highlighting those fears, the WHO said last month it was "deeply concerned" about research into whether H5N1 could be made more transmissible between humans after mutant strains were produced in labs.

Two separate research teams -- one in the Netherlands and the other in the United States -- separately found ways to alter the virus so it could pass easily between mammals.