HANOI, Dec 3 (Reuters) - Fresh bird flu outbreaks have killed more chickens and ducks in Vietnam′s two northern provinces and birds were dying in a third area, the Agriculture Ministry said.

Six outbreaks killed 317 ducks and 37 chickens in the port city of Haiphong and Thanh Hoa province on Thursday, prompting workers to slaughter more than 20,400 birds there, the ministry′s Animal Health Department said in a report seen on Saturday.

In Quang Ninh province 78 ducks and chickens were found dead of unknown reasons on Thursday and some 2,000 birds were culled immediately while bird flu tests were under way, said the deparment′s report on its Web site, www.mard.gov.vn.

Bird flu has killed or resulted in the slaughter of 1.94 million poultry since the virus returned in early October and has now spread to 17 of Vietnam′s 64 provinces, most in the north as winter arrives.

The H5N1 virus which thrives best in cooler temperature has infected 133 people in Asia since late 2003 and killed 68 of them. Vietnam alone has recorded 93 human infections, 42 of them fatal.

Haiphong is home to the country′s latest confirmed bird flu victim, a 15-year-old boy who eventually recovered from the virus after undergoing treatment for a week in November.