Seoul, South Korea (CNN) -- South Korean officials confirmed seven additional cases of foot-and-mouth disease Sunday despite nationwide quarantine efforts, the Yonhap News Agency reported.
Dairy, beef and pig farms were among the locations where investigators detected the disease Sunday.
The government ordered the slaughter of more than 120 animals at those farms to stop the outbreak's spread, according to Yonhap.
Foot-and-mouth disease is a highly communicable disease that affects cattle, swine, sheep, goats, deer and other animals, according to the U.S. Department of Agriculture. It is characterized by a fever and blister-like lesions and erosions on the animal.
Investigators detected the latest outbreak of foot-and-mouth disease in the country on November 28 on a pig farm in the southern city of Andong. The disease has since spread to areas around Seoul in the northern part of the country.
More than 662,647 livestock have been ordered culled -- or slaughtered -- so far across the country, Yonhap said, and at least 81 cases have been confirmed.
The toll of affected livestock is at the country's highest level since 2002, when 160,000 were slaughtered, the Ministry for Food, Agriculture and Fisheries confirmed. Livestock markets have been closed across the country while the government oversees animal vaccinations.
The ministers of public administration and agriculture issued a statement last week saying it was safe to continue eating meat, noting that foot-and-mouth disease does not spread to humans.
CNN's Jiyeon Lee contributed to this report.