Vietnamese state media has reported the country's first death from the deadly bird flu virus strain H5N1 since November 2005. Vietnam made the announcement on Saturday.

The 20-year-old man from northern Vietnam died of the H5N1 strain on Sunday, June 10, at the capital's National Contagious and Tropical Diseases Hospital, the Bangkok Post reported Sunday.

Four others are reportedly infected with the virus. Two have recovered and two are being treated. The latest death brings the total number of Vietnamese deaths from avian flu to 43. Worldwide deaths are at 191, according to the World Health Organization (which has not yet reviewed this latest case).

"This is not going to go away," warned Dida Connor, the WHO's Vietnam communications officer. "There is a sense of complacency which is potentially catastrophic if it was to increase."

It is likely that ducks and other waterfowl are responsible for this last outbreak, according to experts. Ducks can transmit the disease while showing little symptoms and are not as controllable to humans as flocks of birds used for commercial purposes, such as chickens.