African swine fever emerging in China: Distribution characteristics and high-risk areas

African swine fever (ASF) is a highly contagious disease that currently has no specific treatment or vaccine. In August 2018, ASF entered China causing great economic losses. In this study, data on 98 ASF cases in China from August 1^st, 2018 to January 1^st, 2019 were collected and analyzed. Spatio-temporal cluster and directional distribution analysis were performed to characterize the distribution of ASF cases. High risk areas for ASF outbreaks in China were identified using the presence-only maximum entropy (MaxEnt) ecological niche model. The distribution of ASF cases from Aug 1^st, 2018 to Jan 1^st, 2019 in China showed a significant directional trend (northeast-southwest) (P < 0.05) and a spatio-temporal cluster was detected in northeast China. A risk map for ASF infection was developed and pig density was identified as the most important predictor for ASF outbreak. This work presents ASF risk zones in China and may provide useful information for the development of effective strategies for the prevention and control of ASF outbreaks.