Risk Assessment of African Swine Fever Virus Exposure to Sus scrofa in Japan Via Pork Products Brought in Air Passengers’ Luggage

Abstract

In recent years, African swine fever (ASF) has become prevalent in many areas, including Asia. The repeated detection of the ASF virus (ASFV) genome in pork products brought in air passenger’s luggage (PPAP) was also reported from Japanese airports. In the present study, the risk of ASFV exposure to susceptible hosts in Japan via three different pathways was assessed. Two quantitative stochastic risk assessment models were built to estimate the annual probability of ASFV exposure to domestic pigs, which could be attributed to foreign job trainees or foreign tourists. A semi-quantitative stochastic model was built to assess the risk of ASFV exposure to wild boar caused by foreign tourists. The overall mean annual probability of ASFV exposure to domestic pigs via PPAP carried by foreign job trainees was 0.169 [95% confidence interval (CI): 0.000–0.600], whereas that by foreign tourists was 0.050 [95% CI: 0.000–0.214], corresponding to approximately one introduction every 5.9 and 20 years, respectively. The risk of ASFV exposure to domestic pigs was dispersed over the country, whereas that of wild boar was generally higher in the western part of Japan, indicating that the characteristics of the potential ASF risk in each prefecture were varied.

A stochastic assessment to quantify the risk of introduction of African swine fever virus to Taiwan via illegal pork products carried by international travellers

“…Since the beginning of the ASF outbreaks in Asia in 2018, several quantitative risk assessments have been conducted of the release of or exposure to ASFV, or both, in a new country or territory through various pathways (Cho et al, 2021;Ito, Bosch, et al, 2020;Sugiura et al, 2020;Taylor et al, 2020).…”

“…Since the beginning of the ASF outbreaks in Asia in 2018, several quantitative risk assessments have been conducted of the release of or exposure to ASFV, or both, in a new country or territory through various pathways (Cho et al., 2021; Ito, Bosch, et al., 2020; Ito, Jurado, et al., 2020; Jurado, Mur, et al., 2019; Sugiura et al., 2020; Taylor et al., 2020). One study from Japan and another from the United States focused on the risk of ASFV release from PPTs carried by international travellers from multiple countries.…”

“…An evidence-based risk assessment may help to identify countries posing a higher risk through international travellers, evaluate the existing detection methods and recommend cost-effective mitigation strategies. Countries such as the United Kingdom (Adkin et al, 2004;Wooldridge et al, 2006), the United States Jurado, Paternoster, et al, 2019;Mur et al, 2014), Japan (Ito, Bosch, et al, 2020;Sugiura et al, 2020) and Finland (Kyyrö et al, 2017) have conducted quantitative or semiquantitative risk assessment regarding ASFV release from pork products illegally carried by international travellers. reported an annual risk of the release of ASFV through contaminated pork products of flight passengers into the United States at .21 [95% confidence interval (CI): .19−.76], 183.33% higher than what was estimated before the spread of the disease throughout Asia in 2018.…”

“…An evidence‐based risk assessment may help to identify countries posing a higher risk through international travellers, evaluate the existing detection methods and recommend cost‐effective mitigation strategies. Countries such as the United Kingdom (Adkin et al., 2004; Wooldridge et al., 2006), the United States (Jurado, Mur, et al., 2019; Jurado, Paternoster, et al., 2019; Mur et al., 2014), Japan (Ito, Bosch, et al., 2020; Ito, Jurado, et al., 2020; Sugiura et al., 2020) and Finland (Kyyrö et al., 2017) have conducted quantitative or semiquantitative risk assessment regarding ASFV release from pork products illegally carried by international travellers. Jurado, Mur, et al.…”

The potential negative impacts of the classical swine fever virus on wild boar population in Gifu prefecture, Japan

“…Recently, ASF cases have been reported in Asian countries [ 4 ], and previous studies have suggested that the potential risk of ASFV outbreaks and spread might be related to the distributions and habitats of wild boar populations [ 13 , 22 ]. Thus, the staff of wildlife and swine industry need to continuously obtain information on wild boar distribution, properly control the number of wild boars culled, and change the biosecurity level at farms in accordance with wild boar distribution.…”