The deadly pig virus that spread from Africa across Europe and Asia will mean there isn’t enough pork in the whole world to make up for the millions of animals China is slaughtering to try to halt the contagion. But stopping African swine fever isn’t so easy.

The virus that causes the hemorrhagic disease is highly virulent and tenacious, and spreads in multiple ways. There’s no safe and effective vaccine to prevent infection, nor anything to treat it. The widespread presence in China means it’s now being amplified across a country with 440 million pigs—half the planet’s total—with vast trading networks, permeable land borders and farms with little or no ability to stop animal diseases.