South Korea confirms 4th swine fever case in a week

South Korea's African swine fever crisis intensified Tuesday with lab tests confirming the country's fourth case in a week from a farm near its border with North Korea. It raised fears officials are losing a battle to halt the spread of the disease that wiped out pig populations across Asia.

More than 15,000 pigs were culled after the country's first two outbreaks were confirmed last week from farms in the border towns of Paju and Yeoncheon, but officials have yet to identify the infection route. The disease may have crossed from North Korea, which reported an outbreak near its border with China in late May.

In a closed-door briefing to lawmakers on Tuesday, South Korean National Intelligence Service Director Suh Hoon said the North continued to see new cases after July despite national efforts to stem the spread of the illness, including culling and disinfection operations and restrictions on distribution of pork products, lawmaker Lee Eun-jae said.

Lee did not mention whether the spy agency described how it obtained the information.

South Korea's Ministry of Agriculture, Food and Rural Affairs confirmed the country's fourth case at another farm in Paju, which raised some 2,300 pigs, after blood tests confirmed that the disease caused three miscarriages in the animals.

The ministry's announcement came hours after the country's third case was confirmed Monday night at a farm in Gimpo, which is on the southern side of the river that separates the border region and the metropolitan area surrounding Seoul, where about half of South Koreans live.

African swine fever is harmless to people, but spreading from farms to densely populated areas will make it harder to contain. The illness is highly contagious and fatal for pigs, with no known cure.

In South Korea, where diets rely heavily on pork, there is concern the outbreak could spread and hurt an industry with 6,300 farms raising more than 11 million pigs.

The disease decimated pig herds in China and other Asian countries before reaching the Koreas.

Officials have said the first three weeks will be crucial in efforts to prevent the outbreak from spreading, considering incubation periods. They strengthened quarantine and prevention measures at border area farms and the facilities that traded with them while tightly restricting the movement of farmers, animals and vehicles.

Since Monday evening, the government has imposed a 48-hour standstill on farms, slaughter houses and feed factories in Gyeonggi province, which governs the three towns where infections were reported, as well as the nearby Gangwon Province and metropolitan city of Incheon. Government workers dressed in lab coats and masks were seen guarding road blocks