A fresh case of the highly infectious bird flu H5N1 virus has been discovered at a duck breeding farm in Cheonan, located in central Korea 57 miles south of Seoul.

The South Korean Ministry of Agriculture and Forestry said Thursday that this is so far the seventh dangerous bird flu outbreak confirmed in the country since Nov. 25 of last year. The case was first reported on Tuesday when 31 ducks died and was confirmed Thursday as "highly pathogenic" bird flu.

As a precautionary measure, quarantine officials will immediately begin culling over 55,000 poultry within a 2-mile radius.

The six previous outbreaks were confirmed to be the H5N1 virus. The first outbreak in three years was reported last year on a poultry farm in Iksan.

South Korea killed over 5 million birds in 2003 and 2004 to curb the spread of the disease. More than 160 million people worldwide have died of bird flu since 2003.

In recent months South Korea culled more than 2 million birds.

No South Korean has been reported to be infected.