The Chinese Ministry of Health confirmed yesterday that a 29-year-old woman in Shanghai has died from bird flu.

The victim, identified only by her surname, Li, was a migrant worker. The ministry did not identify her hometown.

Li began running a fever and experiencing pneumonia symptoms on March 13 and died on Tuesday.

The Shanghai Municipal Center for Disease Control and Prevention said Li tested positive for the virulent H5N1 strain of the disease. The municipal health department reported on Thursday that woman was a suspected bird flu victim.

Also on Thursday, the national CDC re-tested Li's samples, which were also positive.

People who had come in close contact with Li were put under medical observation by city health authorities. As of last night, no abnormal symptoms had been reported.

Authorities said there are no reports of bird flu among poultry in the city and they have not been able to determine how the woman became infected with the disease.

Shanghai's health authorities have intensified surveillance and preventive measures in the wake of the woman's death.

The city's 160 medical departments with fever outpatient service have stepped up patient screening.

All hospitals were ordered to isolate suspicious human cases, strengthen disinfection and provide medical workers with training on the fatal disease.

In addition, controls have been tightened in animal and poultry trading, including increased sterilization of markets.

Booklets on bird flu prevention have been sent to communities to raise public awareness about the disease.

"There's no need to panic, but it's necessary to pay close attention to personal hygiene and avoid contact with sick or dead poultry," said Zhang Yongxin, a professor at Huashan Hospital.

Experts have been worrying that the bird flu virus could mutate into a form that could spread easily among people, causing a global pandemic.

China has agreed to share virus samples from bird flu outbreaks in poultry with the WHO to help develop treatment drugs and vaccines, according to WHO officials.

The first batch of 20 samples should arrive at WHO overseas laboratories within weeks, said Julie Hall, coordinator of Epidemic Alert and Response in WHO's Beijing office.

Shanghai last had an outbreak of avian flu among poultry in 2004.

The new death brought China's total number of human cases of bird flu to 16. Eleven people have died.

Globally, 185 human cases of bird flu involving 104 deaths had been reported to the WHO as of yesterday.