Vietnam yesterday reported two more bird-flu deaths, bringing the human toll to nine in three weeks and further raising the threat of the disease emerging as the next global pandemic, officials said.
The string of deaths -- which include five this week alone -- has prompted the UN-affiliated World Health Organization (WHO) to ring alarm bells about the high fatality rate -- more than 70 percent of those infected have died. It has also warned that there's a lack of field research to answer critical questions about how it's transmitted, especially since no vaccine or effective treatment exists.
The WHO and other health experts fear that avian influenza could evolve into the next global pandemic if the virus mutates and widespread human-to-human transmission occurs. There is, however, no evidence of that yet.
A 35-year-old woman from the southern Mekong Delta province of Dong Thap became the latest victim to die on Friday, a day after being admitted to the Hospital for Tropical Diseases in Ho Chi Minh City, said Nguyen Ngoc An, director of Dong Thap's Preventive Medicine Center.
She tested positive for the H5N1 strain of bird flu after developing a high fever a week after slaughtering a duck, An said. None of her relatives who ate the bird showed any sign of the disease, An said, adding that the woman did not eat the poultry.
An said authorities suspected the woman might also have been infected by stork droppings in her lotus pond where she often worked.
A 17-year-old boy from southern Bac Lieu province, who died on Jan. 15, also tested positive for bird flu, a local health official said on condition of anonymity. The boy slaughtered a chicken before showing bird-flu symptoms, officials said.
The WHO is also investigating a case involving two brothers in the north who tested positive for the H5N1 bird flu strain, said Hans Troedsson, WHO representative in Hanoi. The older brother has died and the younger brother remains hospitalized in Hanoi.
The case has raised new fears of human-to-human transmission, but the WHO says on its Web site that isolated instances of transmission among humans can be expected and would not raise the threat of a pandemic. Vietnamese officials have also said the two brothers may have been infected after the family ate duck blood pudding that had not been boiled.
The WHO has warned that the outbreak is gaining momentum as Vietnam's busy Lunar New Year approaches next month.
About 410,000 birds have died or been slaughtered in Vietnam this year, with about half of those deaths occurring this week, according to government figures.
Thailand also reported its first poultry outbreak in two months, after chickens tested positive for H5N1.
WHO officials have warned that surveillance must remain high.