Bird flu kills woman in VietnamStory Highlights
Test results show she was infected with the H5N1 bird flu virus
Health authorities are not sure how she got infected
Health experts worry the virus could mutate into a form that passes among people
Bird flu killed a school teacher from northern Vietnam in the country's 51st death from the disease, and health officials fretted Tuesday that the virus would spread further.
The woman, 23, was infected in Phu Tho province, some 50 miles northwest of Hanoi. She died in a Hanoi hospital Monday morning, said Nguyen Huy Nga, director of the Health Ministry's Preventive Medicine Department.
Test results showed that she was infected with the H5N1 bird flu virus. It was the country's 51st reported human death from bird flu since the virus began raging through Asian poultry stocks in late 2003.
Nga said outbreaks of the virus in poultry were still being reported.
"The risk of bird flu infection among people remains very high, and we expect more human cases," Nga said.
The woman developed bird flu symptoms on February 14 and died Monday after being treated at the National Tropical Disease Hospital for four days, Nga said.
Nguyen Duc Mao, director of Phu Tho's Preventive Medicine Bureau, said health authorities are still unclear how the woman got infected.
"A few hundred chickens died in the school neighborhood, but they tested negative for the bird flu virus," Mao said. "We still don't know how she was infected."
Bird flu remains hard for people to catch, but health experts worry the virus could mutate into a form that passes easily among humans, sparking a pandemic. So far, most human cases have been linked to contact with infected birds.
At least 232 people have died worldwide from the virus, according to the World Health Organization. Vietnam's latest bird flu death was not included in the WHO's tally
