HANOI -- A 23-year-old woman has been infected with bird flu in Vietnam, the second human case confirmed since the beginning of the year in the country, a health official said Sunday.

"The patient test result was positive to H5N1," said Nguyen Quoc Hung, deputy director of northern Quang Ninh provincial hospital, referring to the deadly strain of avian flu.

The woman has been under treatment for five days at the hospital, where another doctor said on condition of anonymity that her health was "not very good", without further elaborating.

According to health officials, the woman, who fell ill on January 28, had eaten chicken. Sick and dead poultry has been discovered in her neighborhood.

The first human H5N1 case this year in communist Vietnam was an eight-year-old girl from northern Thanh Hoa province who has now recovered.

Her 13-year-old sister died in the hospital earlier but was not tested for H5N1 before the burial, health officials said.

The country has recorded 52 human deaths from bird flu, the second highest toll after Indonesia, where the virus has killed 115 people.