An outbreak of bird flu was confirmed at a commercial poultry farm in Maryland at the weekend, prompting officials to order the slaughter of around 328,000 birds in a bid to contain the disease.

State agriculture officials said a Maryland farm with around 118,000 chickens was found to be infected. The officials ordered the slaughter of those birds, as well as 210,000 other birds at another poultry farm which is situated about a mile away from the infected farm, reported the Associated Press.

A quarantine was set up covering eight farms within a two-mile radius, while tests are to be carried out on 79 poultry farms within a six-mile radius of the infected farm.

Officials have not found a connection between the infected Maryland farm and the nearest infected farm in Delaware, 45 miles away, but have not ruled out a link between the cases.

The Maryland outbreak is believed to be the H7 strain, which is not believed to be harmful to humans. A similar strain was recently found in Delaware.