It has been three weeks since the first outbreak of bird flu in Korea and five new suspected cases have been reported since the start of the Lunar New Year holiday.
The Agriculture Ministry said Monday there is a high chance that three duck farms in central North Chungcheong Province have been contaminated.
However, it confirmed that one chicken farm in southwestern North Jeolla Province and another in South Gyeongsang Province that were suspected of being affected are free of the disease.
The highly pathogenic H5N8 strain was confirmed in migratory ducks in South Jeolla Province on Monday after fowl were found dead there a week ago. Forty farms have been contaminated so far, and at least 2.6 million ducks and chickens have been culled at 115 farms.