South Korea's Agriculture Ministry confirmed the country's fourth case of African swine fever on Tuesday at a farm in Paju, near the inter-Korean border. <br /> This comes a day after the third case was confirmed in Gimpo, the first case south of the Hangang River.<br />The government is ramping up efforts to prevent any further spread, including culling pigs within a three kilometer radius of the affected farms.<br />Local authorities are also inspecting waterways that connect to North Korea.<br />Starting next month, South Korea's Rural Development Administration will work with Vietnam to discover the route of the spread as preliminary research toward a vaccine.<br />African swine fever currently has no vaccine, and is fatal to pigs, but harmless to humans. <br />
