A variant of AI identified as H5N1 killed six person in Hong Kong in 1997 and the South Korean Authorities have asked for US help to check whether this latest virus is the same strain.
Authorities are now monitoring all duck hatcheries, slaughterhouses, intensifying disinfection measures, restrict transport of birds, investigating migratory birds.
About half of the target 1 M chickens and ducks had been slaughtered and buried after an outbreak of bird flu. The total includes thousands of chickens who died instantly from the disease.