The Economic Impact of Classical Swine Fever in Japan

Abstract

Classical swine fever (CSF) is a highly contagious disease in domestic pigs and wild boars that causes devastating economic losses. In September 2018, an outbreak of CSF reemerged in Japan after 26 years of absence of any case. After confirmation of the first case, disease control measures such as culling all pigs in infected farms and movement restriction on the surrounding farms were conducted. In addition, biosecurity measures were enhanced by constructing fences around the farms and oral vaccination were conducted to prevent the disease spread among wild boars. Despite conducting such measures, CSF continued to spread. The purpose of this study was to estimate economic losses when the CSF spread continues without any additional control measures such as vaccination to domestic pigs to provide information to discuss the necessity of applying such measures. To estimate the economic losses from the CSF outbreak in Japan, we simulated CSF infection in pig farms using a simple stochastic model assuming the CSF infection in wild boar spread concentrically and defined proportion of pig farms in the area with infected wild boar becomes infected. As a result, when the infection in wild boar spreads to a radius of 500 km, the total losses paid by the government amount to approximately 7 hundred million US$ which include compensation for infected farms and labor costs, and the loss due to the reduction in pork production would be about 1.3 billion US$. As this study was not considered effect of the vaccination to domestic pigs that started from the end of October 2019, the losses estimated in this study can be overestimated. Still, in the context of ongoing CSF epidemics, the importance of providing a prompt information to discuss the necessity of conducting additional control measures will be highlighted. This study will be helpful to predict the spread of an infectious disease and to estimate its cost during an epidemic.