In Southeast Asia, health officials are warning an outbreak of the highly contagious pig disease known as African swine fever is spreading and on track to become what some epidemiologists are calling the “biggest animal disease outbreak” ever recorded. Swine fever, which causes internal bleeding in pigs and spreads rapidly in dense factory farms, has appeared in China, Vietnam, Mongolia and Cambodia, with reports of a new outbreak in North Korea. Health officials estimate China may be gearing up to slaughter up to 200 million pigs ahead of schedule in an effort to quarantine the outbreak.