Date Received: 23-12-2021 / Date Accepted: 05-07-2022
African swine fever (ASF) is a highly contagious disease with a mortality of up to 100%, resulting in high economic losses. In Vietnam, ASF was first reported in February 2019 and quickly spread to all provinces. This study aimed to estimate the basic reproduction number (R0) and developed a dynamic model to explain how ASF spreads in the pig herd during the first epidemic year to suggest vaccine coverage level required to prevent future outbreaks. The outbreak data were collected from 6 large-scale fattening farms within the first wave of ASF outbreaks. Two methods were used to estimate the R0including the Exponential Growth method (EG) and Maximum Likelihood method (ML). The average R0values were estimated at 2.97 (95%CI: 2.44-3.59) and 3.18 (95%CI: 2.52-3.96), respectively. Based on the worst-case scenario, all pigs in a herd would be infected and removed within 50 days. The vaccination rate ranges from 75-94% of pigs in each farm depending on the vaccine effectiveness.
