Evaluation of Transmission Parameters of Three Korean African Swine Fever Virus Isolates: A Bayesian ABC‐SMC and Agent‐Based Modeling Approach

African swine fever (ASF) remains a major threat to global pig production. An understanding of within‐pen transmission dynamics is essential for designing effective prevention and control. Three independent direct‐contact (DC) transmission experiments were conducted using Korean ASF virus (ASFV) isolates representing distinct epizootic phases in the Republic of Korea: Korea/Pig/Paju1/2019, Korea/Pig/Yeongwol/2021, and Korea/Pig/Hongcheon/2023. In each experiment, two inoculated donor pigs were cohoused with five DC‐susceptible pigs for up to 18 days postinoculation (dpi). Transmission parameters were estimated using two complementary modeling approaches. First, an approximate Bayesian computation sequential Monte Carlo (ABC‐SMC) framework was applied to a deterministic susceptible–exposed–infectious–removed (SEIR) ordinary differential equation (ODE) model. Second, a stochastic agent‐based model (ABM) was used to validate parameter estimates and quantify within‐pen outbreak probability. All DC pigs in the three experimental groups developed ASFV infection and died within 18 days postexposure. The Bayesian SEIR model estimated transmission coefficients ( β ) of 0.503, 0.435, and 0.308 per susceptible–infectious pair per day for Paju, Yeongwol, and Hongcheon isolates, respectively. Notably, the Korea/Pig/Hongcheon/2023 isolate exhibited a shorter posterior latent period ( ε  = 3.78 days; 95% credible interval [CrI]: 2.78–4.83) than Korea/Pig/Paju1/2019 ( ε  = 7.23 days; 95% CrI: 5.36–9.48) and Korea/Pig/Yeongwol/2021 ( ε  = 6.11 days; 95% CrI: 4.57–7.73). ABM simulations using posterior parameter distributions yielded per‐donor secondary infection estimates ( R _pd ; the mean number of DC pigs infected per‐donor pig, structurally bounded by the pen size) of 1.95, 2.10, and 2.37 for the Paju, Yeongwol, and Hongcheon isolates, respectively. In sensitivity analyses, the shorter latent period of the Hongcheon/2023 isolate was consistently observed under alternative exposure‐time assumptions, distance‐function weightings, and prior specifications, although the absolute values of β and ε depended on the assumed exposure time. This study provides the first comparative analysis of within‐pen transmission dynamics for multiple Korean ASFV isolates. Although overall transmission potential was similar across isolates, the Korea/Pig/Hongcheon/2023 isolate exhibited a shorter estimated latent period and a marginally higher R _pd . Because isolate identity was confounded with experiment year, this difference requires confirmation in contemporaneous experiments; nevertheless, it may have implications for early detection and rapid spread within pig facilities.