The latest infection was at Dinajpur town, 410 km (250miles) from the capital, said Salehuddin Khan, director of thegovernment's livestock department.
Bird flu was first reported near the capital in March lastyear and has since spread mainly to northern districts, forcingauthorities to kill more than 300,000 chickens.
Since March, 69 farms in 20 districts have been infectedwith the H5N1 virus.
There are around 150,000 poultry farms in Bangladesh, withan annual turnover of $750 million, officials said.
About 4 million Bangladeshis are directly or indirectlyassociated with poultry farming, but so far there have been nocases of human infection in the densely populated country,government and health officials say.
Experts fear the bird flu virus might mutate or combinewith the highly contagious seasonal influenza virus and spark apandemic that could kill millions of people.
Bird flu has killed more than 210 people in 12 countriessince 2003, the World Health Organization says.
(Reporting by Ruma Paul; Editing by David Fogarty)