The devastating outbreak of the disease that has led to millions of pig deaths in East Asia has intensified efforts to develop a vaccine quickly, but the virus presents several challenges that are yet to be overcome.
African swine fever, a fatal disease of pigs, has been around for decades. Believed to have originated in sub-Saharan Africa, it’s made several visits to other continents, with outbreaks surfacing in Russia, Brazil, and various parts of Europe—where it still maintains a stronghold in wild boar populations.
But it only escalated to what Dirk Pfeiffer calls “the biggest animal disease outbreak ever” when it reached China last August, spreading like wildfire across the world’s largest pig congregations. “There’s so many pigs in China, it was just a matter of time,” says Pfeiffer, a veterinary epidemiologist at the City University of Hong Kong and the UK’s Royal Veterinary College.