Vietnam is testing samples from two more suspected bird flu cases, one of whom has died, as the country grapples to control a strain of the illness that has killed dozens and ravaged the region’s poultry industry.

An 18-year-old woman from Hau Giang province in the Mekong Delta died on Monday, said hospital official Le Van Dieu in southern Can Tho city. The woman displayed high fever and coughing, symptoms similar to those caused by bird flu.

If confirmed, this would take the death toll to 24 since outbreaks of the H5N1 strain were first reported in December 2003 in the Mekong delta and would be the fourth person to die from the illness in less than two weeks.

A 16-year-old girl who battled bird flu for more than a fortnight, died on Saturday.

State media said on Tuesday the latest victim had eaten sick chickens in December, after which she became ill.

“We are having her samples tested,” Dieu told Reuters, referring to the woman hospitalised in Can Tho city.

Officials at Ho Chi Minh City’s Pasteur Institute, which was conducting the tests on the woman’s samples, could not be reached for comment.

The three deaths since December 30 were from southern Vietnam.

The H5N1 virus also killed 12 people in Thailand last year but no new cases have been reported there since November.

The Nguoi Lao Dong (Labourer) newspaper said doctors in Ho Chi Minh City were testing samples from a second person, a 15-year-old girl, whose elder sister was confirmed by health officials on Monday to have been infected by the H5N1 virus.

The World Health Organization has warned Vietnam it may face new bird flu cases this month as poultry is moved around the country ahead of the mid-February Lunar New Year celebrations.

The virus becomes more active when temperatures cool, the WHO said.

Market inspectors have tightened quarantine checks on poultry at the city and all markets in Ho Chi Minh City, Vietnam’s largest population centre with nearly 10 million people, and the capital Hanoi to the north.

In the past six weeks, more than 108,000 poultry had been either slaughtered or had died of bird flu in Vietnam, mostly in the south, the Agriculture Ministry said. Last year, the epidemic wiped out 17 percent of Vietnam’s poultry stock of 250 million.