Image: Pirbright Institute
In 2018, China reported an outbreak of the Georgia 2007 strain in Shenyang, a city in the country’s northeast. From there, it swept through the world’s largest congregations of pigs and among countless small farms, killing hundreds of thousands of animals across China. By the end of October 2019, nearly 200 million animals had been culled in a desperate effort to stop the virus, but ASFV continued to spread, popping up in Mongolia, Vietnam, Cambodia, Laos, Myanmar, South Korea, and the Philippines. In October, Mark Shipp, the president of the World Council of Delegates of the World Organization for Animal Health, told reporters that around a quarter of the global pig population could die due to the disease.
Unrelated to the East Asian epidemic, new outbreaks have also been reported in Eastern Europe. There, low levels of the virus have been circulating in wild boar and domestic pig populations for more than a decade since it arrived from its native Africa, where it often leaps from wild pigs to domestic animals. The rapid spread of ASFV across Eastern Europe and Asia alarmed officials in Asia, Western Europe, and North America, concerned that the virus could slip into their countries via contaminated pork products or animal feed imported from infected countries. Seemingly overnight, finding a vaccine for ASFV—a virus that had long stood at the periphery of the scientific community’s attention—became a global research priority.