African Swine Fever in China
Increased ASF Outbreaks Raise Questions About Herd Recovery
Reported outbreaks of ASF in China have risen over the past several months, with new outbreaks reportedly occurring in at least five separate provinces, as shown in Figure 1. Note: This list of outbreaks may be incomplete as it is compiled from both official reports to the World Organization for Animal Health (OIE) and various news reports. Contributing to the rise in outbreaks have been new mutant variants of the virus. Two specific strains that have recently been detected reportedly are less virulent than previous strains, which makes them more difficult to detect and thus easier to spread between pigs because the disease goes undetected, making it even harder to control ASF. This is particularly bad for piglets born with weakened immune systems. The source of these mutations is still in question, but several experts point to the use of unapproved and illegal vaccines in significant portions of the herd as a source.