HANOI, Aug 7 (Reuters) - Bird flu has killed a teenager in northern Vietnam, the second death from the poultry virus within a week, state-run Vietnam Television (VTV) quoted Health Ministry officials as saying on Tuesday.

The 15-year-old victim died last Saturday while on the way to a Hanoi hospital from the northern province of Thanh Hoa, a VTV news bulletin quoted health officials as saying without giving the name or gender of the deceased.

Laboratory tests in Vietnam have confirmed the patient had contracted the H5N1 virus, bringing to seven the number of human infections so far this year and the Southeast Asian country"e;s fourth death from bird flu in 2007.

The teenager developed a fever and received preliminary treatment in Thanh Hoa province before being rushed to Hanoi.

The World Health Organisation (WHO) has not confirmed the latest infection from bird flu, which killed a 22-year-old pregnant woman from northern Vietnam on July 27.

The poultry virus has killed 46 of the 100 confirmed cases in Vietnam since late 2003, including the latest death.

Globally, the H5N1 virus has killed 192 people out of 319 known cases, according to a WHO tally. Hundreds of millions of birds have died or been slaughtered.

The H5N1 virus remains mainly a virus of birds, but experts fear it could mutate into a form easily transmitted from person to person and sweep the world, killing millions.