HANOI, Aug 24 (Reuters) - Bird flu has spread to two more provinces in Vietnam, killing hundreds of chickens and ducks, the Agriculture Ministry said on Friday.

The outbreak of H5N1 in the northern province of Thai Nguyen and Dong Thap to the south brought to four the number of provinces on the government"e;s current bird flu watchlist.

Vietnam has 64 provinces.

A total of 150 ducks and 35 chickens fell sick on Wednesday in Thai Nguyen, 80 km (50 miles) north of Hanoi, and tests have confirmed they had the H5N1 virus, the ministry"e;s Animal Health Department said in a report.

The virus also struck a farm in the southern Mekong delta province of Dong Thap where 250 chickens were found dead on Sunday, it said.

Bird flu has infected seven people in Vietnam so far this year, four of whom have died, bringing the death toll since late 2003 to 46, the government said.

Globally, the H5N1 virus has killed 195 people out of 322 known cases, according to a tally of the World Health Organisation. Hundreds of millions of birds have died or been slaughtered.