As bizarre as this may sound, one major reason the disease disseminated as rapidly as it did is because of the Chinese government’s measures to combat pollution.

In 2015, in order to prevent water from being contaminated by animal feces and other waste, the authorities began to heavily regulate — and in some places, ban — livestock breeding in certain water-rich areas in the south. Yet instead of giving industrial pig farmers enough time to upgrade their facilities in compliance with new waste-disposal standards, local governments quickly dismantled pig farms, leading to a major cutback in production in the south.

But pork is China’s favorite meat, and so, fearful of a shortage, in April 2016 the central government mapped out a strategy called “nanzhu beiyang”: “raising pigs in the North for consumption in the South.” Much of the production became concentrated in northern China, and the livestock was then transported long-distance to the south.

Of the 689 million pigs that China produced for slaughter in 2017, 102 million were taken across provinces, according to the agriculture ministry — a practice that posed a major biosecurity risk as soon as the first outbreak of swine fever was identified in Liaoning, in the northeast. (The disease is extremely contagious, and though it doesn’t harm humans, they can spread it.) In fact, some 45 percent of the 87 outbreaks reported by mid-December 2018 involved long-distance transport. Call this problem No. 1.

At that point, the spread of the disease could still have been prevented with accurate and timely reporting. This, presumably, is the reason that China’s Law on Animal Epidemic Prevention prohibits “cover-up, misreporting, late reporting and underreporting” of any animal diseases. Other government regulations stipulate that once an infected pig is identified on a farm, the farm’s entire stock must be culled.

Enter problem No. 2: The central fiscal authorities were called on to cover only part of the compensation to farmers, leaving local governments to shoulder the rest. But by the end of June 2019, China’s local authorities had amassed a total debt of at least 21 trillion yuan (more than $3 trillion), according to the Ministry of Finance — about 23 percent of China’s gross domestic product in 2018. And so even as the authorities in Beijing instructed local governments “to resolutely defend and prevent further spread and dissemination of the disease,” those local governments — given the financial burden they would have to bear to cover any culling of stock — had an incentive to not report the disease.

In Shandong Province, even though there were suspected outbreaks immediately after August 2018 and pig inventories soon dropped significantly, only one outbreak at one farm (involving 17 sick animals) had been reported by February 2019. While some farmers were saying that swine fever was spreading like fire in Zhaoqing, Guangdong Province, the local authorities did not officially disclose the problem. And when they did respond to farmers’ requests for compensation, the authorities provided amounts that were often much lower than what the central government had stipulated.