It might look as though the Communist Party is in complete control of mainland China, but there’s a new threat to social stability: African swine fever is devastating the pig population. With pork prices skyrocketing and the virus spreading across the globe, the specter of a crippling pork shortage looms. That has Beijing worried. Pork makes up about 60% of Chinese meat consumption, which accounts for nearly half the world’s pork market. Shortages and price spikes, combined with dissatisfaction over slowing economic growth and increasing repression, could produce political unrest. That’s the last thing Beijing wants.

Food riots have been a cause of major political crises in the past. They’ve even sparked revolution, as in France in 1789 and Russia in 1917. While the modern global agricultural system is more resilient than in past centuries and the modern diet often more varied, China remains vulnerable to an exogenous shock to food prices. It’s hard to know the real feelings of China’s heavily oppressed populace, but there are signs that they are beginning to blame the government for slow action, much as they did after the 2002-2003 SARS epidemic. The prices for other protein, such as beef, are also rising, while pig farmers are angry at government delay in compensating them for their losses.

The virus isn’t new. The first cases of African swine fever appeared in the early 20th century, with major outbreaks over the decades. It is a hemorrhagic viral disease spread by infected meal or meat or contact with an infected pig. There is no vaccine, and infected pigs don’t recover.

Around half of China’s pig population—estimated at 300 million before the pandemic—have died or been culled since the first outbreak in August 2018. The real death count may be higher, given Beijing’s record of sloppy accounting and fear of releasing bad news. The virus has spread to Vietnam, Laos, South Korea, the Philippines, East Timor and eight European nations. The pandemic shows no signs of slowing, and U.S. hog farmers fear that it could jump to American shores. That would make for a global catastrophe.

The destruction of so many hogs has driven Chinese pork prices up by more than half and they’re expected to hit record levels—70% above what they were last year—by the end of 2019. That’s more than enough to worry the government. In response, Beijing has begun purchasing more pork from abroad, including 146,000 metric tons of U.S. pork between mid-February and May this year. This early intervention has kept the situation manageable, and China still has pork stocks on which it can draw. Substitution of chicken and beef will further ease the food-supply strain—something Beijing is encouraging.