Clinical symptoms of African swine fever in domestic pig farms in the Republic of Korea, 2019.

This study describes the clinical characteristics of the African swine fever (ASF) outbreaks in 14 domestic pig farms in the Republic of Korea. ASF outbreak was identified by farmers' notifications in 11 farms and by active surveillance in the remaining three. At the time of notification, farmers reported sudden death, abortion and anorexia in sows. Death was the primary symptom identified by farmers in fattener pigs. The number of animals exhibiting clinical symptoms did not exceed four heads at notification, and the number of asymptomatic virus positives was four heads per farm on average. As ASF virus was detected only in the same pig house (in a pen for fattener pigs) in each of 14 ASF outbreak farms, there has been no evidence of house-to-house viral spread within any of the ASF outbreak farms. This in turn supports our hypothesis that infection was successfully detected during its initial phase.