South Korean authorities have culled some 201,000 birds in the southwestern region of the country to contain the spread of highly pathogenic avian influenza that broke out on its poultry farms.

The Animal and Plant Quarantine Agency of South Korea has slaughtered some 201,000 birds between Nov. 18 and Dec. 22, after the H5N6 strain was found in four different farms in Jeongeup, Gochang and Yeongam, reported the South Korean agency Yonhap.

South Korea has already tightened its control over the southwest region's farms in early December as they are the country's biggest producer of poultry products.

The APQA already culled another 76,000 birds in early December at five farms in the area after detecting another breakout.

The South Korean Minister of Agriculture, Food and Rural Affairs, Kim Yung-rok, has called for measures to disinfect every farm to stop the spread of the virus.

Highly pathogenic avian influenzas, commonly known as bird flu are viruses that cause serious illness in birds and result in high mortality rates, according to the World Health Organization.

In 2016, South Korea culled over 30 million birds to contain the worst outbreak of bird flu in the country's history.