Peste des petits ruminants (PPR) is a highly infectious transboundary disease of small ruminants caused by peste-des-petits-ruminants virus. It is one of the most destructive diseases in sheep industry in Africa, Asia and the Middle East. In Pamir Plateau, India, Pakistan, Afghanistan, Tajikistan, Kazakhstan and other countries bordering Tibet and Xinjiang of China are all PPR epidemic areas. Within this region, there are many big population size wild small ruminants, moving freely across the border. The time-honored transboundary nomadic lifestyle results in transboundary migration of livestock too. China has experienced two national epidemics, which can be sourced back to Tibet and Xinjiang. In order to reach the China National Plan for the Eradication of Peste des Petits Ruminants and construct a national wide free zone without immunization in 2020, effective control of transboundary spreading and imported cases is an unavoidable choice. For the countries in the pan Pamir Plateau, the spatial risk distribution of PPR were predicted by a variety of eco-geographical, anthropoid and meteorological variants first time; by the resistance surface analysis, maximum available transboundary paths for PPR spreading by small ruminants were calculated. Finally, 5 paths were obtained, respectively from Kazakhstan, Tajikistan, Pakistan and Kashmir to enter Xinjiang and Tibet of China through different channels. This study not only confirmed the fact of transboundary communication of small ruminants for the first time, but also provided specific objectives for PPR prevention. This research can also provide new methods for the prevention and control of other transboundary infectious diseases.
African swine fever (ASF) free China has experienced a sudden multi-focal and multi-round of outbreaks during 2018. The subsequent epidemiological survey resulted in a debate including the possibility of a transboundary spread from European Russia to China through wild boar. We contribute to the debate by assessing a potential Trans-Siberian transmission path and its associated ASF arrival dates. Least Cost Paths (LCPs) between Eastern Europe and NE China were plotted. The arrival dates of ASF-infected wild boar have been predicted by cumulative maximum transmission distances per season and cover with their associated minimum time intervals along the LCPs. Our results show high costs for wild boar to cross Xinjiang, NW China and/or Mongolia to reach NE China. Instead, the Paths lead almost straight eastward along the 59.5° Northern latitude through Siberia and would have taken a minimum of 219 or 260 days.