Emergence of African swine fever in Taiwan: epidemiology and control strategies

African swine fever (ASF) is a rapidly fatal infection in pigs caused by ASF virus (ASFV). ASFV was first identified in sub-Saharan Africa in the 1900s, spread to Europe in the 1950s, and finally to China, the world’s largest pork-producer, in 2018. Although no definite previous outbreak had been confirmed in Taiwan, ASFV DNA had been detected from a pig carcass washed ashore and smuggled pork-products from Southeast Asia in 2021. On 10 October 2025, suspicious pig deaths were observed in a pig farm in the Wuqi District in Taichung, Taiwan, and subsequently confirmed to be due to ASFV. A total of 117 pigs in the index farm had died and all the remaining 195 pigs in the farm culled. A nationwide ban on pig transport and slaughtering and use of food-waste for pig farming was implemented. Sequence analysis revealed that the ASFV strain was a genotype I/II recombinant, sharing >99.9% nucleotide identity with China/Vietnam strains. It was suspected that the source of the outbreak was from inadequately sterilized food-waste for pig-feeding. So far, all samples from other pig farms in the nationwide surveillance were ASFV-negative. Currently, no specific antiviral agent or vaccine is available for ASF infections. Prevention and control require a multifaceted approach combining biosecurity, surveillance, rapid molecular diagnosis, culling, and international cooperation. At the moment, the outbreak was likely limited to a single farm and was apparently eradicated. Continued surveillance and other control measures remain essential to protect our pig populations and minimize economic losses.