Abstract:Risk analysis can be used to guide decision-making processes to prevent the spread and outbreaks of disease. We documented the risk factors for Grass Carp Hemorrhage (GCH) by analyzing epidemic data and epidemiological investigations. Using this information, we constructed a model to estimate the risk of GCH outbreak. The model included a risk index system, established using an analytical hierarchy process (AHP), risk weightings, determined using the Delphi method, and risk results, expressed using the synthetic evaluation method. The risk index system included 9 guidelines (B1–B9) and 26 risk hazard factors (C1–C26). The guidelines included: B1 fry, B2 immunity, B3 water quality, B4 rearing density, B5 water temperature, B6 feed and management, B7 outbreak history, B8 weather, and B9 pond status relative to guidelines. The primary risk hazard factors included: C1 fry bringing virus or not, C4 fry accepting vaccine or not, C6 health status when immunized, C13 rearing density, C14 water temperature, C19 outbreak history of GCH. The risk weights set for the nine guidelines were ={0.167, 0.202, 0.124, 0.109, 0.101, 0.097, 0.092, 0.081, 0.064}. The highest weightings were applied to B2 and B1. We conducted a synthetic evaluation to calculate the risk value using the following model: . We used this model to assess the level of risk in three areas, Central China, Southwest and Southern China. Our results suggest that the risk of outbreak was lowest in Southern China (0.568) and higher in the other two locations (Central China: 0.699, Southwest China: 0.690).