Estimation of infection risk on pig farms in infected wild boar areas – epidemiological analysis for the reemergence of classical swine fever in Japan in 2018

Publication date: Available online 19 December 2019Source: Preventive Veterinary MedicineAuthor(s): Yoko Hayama, Yumiko Shimizu, Yoshinori Murato, Kotaro Sawai, Takehisa YamamotoAbstractIn September 2018, classical swine fever (CSF) reemerged in Japan after 26 years’ absence. The first case was detected at a pig farm in Gifu Prefecture, in the center of Japan, and the disease spread to both domestic pigs and wild boar (Sus scrofa). The spread of CSF in wild boar is extremely difficult to control and is thus a great threat to domestic pig farms, and understanding the transmission risk from wild boar to domestic pigs is essential to implement effective control measures that will prevent domestic pig infection. Therefore, this study elucidates the transmission risk from wild boar to domestic pigs by introducing a transmission kernel that is dependent on the distance between infected wild boar and pig farms, and then estimating the risk area of infection from wild boar by describing the transmission probability. The study used epidemiological data from Gifu Prefecture in the period from September 2018 to March 2019, including a total of 171 1-km grid cells where an infected wild boar was detected and pig farm data from 13 infected and 34 uninfected farms. The estimated infection risk area within 28 days matched well with the observed data. The risk area widened gradually during the epidemic, and at the end of March, the risk area extended over a range of approximately 75 km f...
Source: Preventive Veterinary Medicine - Category: Veterinary Research Source Type: research