Sex-based Differences in the Distribution of Aujeszky’s Disease-Seropositive Japanese Wild Swine

Abstract

Abstract Background: Aujeszky’s disease virus (ADV) primarily infects domestic and wild swine, causing the abortion and death of young piglets due to central nervous system disorders. In Japan, the national eradication program has been successful in most prefectures; however, ADV-infected wild swine have been concerned as a source of ADV among domestic pigs. Results: This study assessed the nationwide seroprevalence of ADV among wild swine (Sus scrofa) in Japan. Moreover, sex-based differences in the spatial clustering of seropositive animals were investigated. In total, 1383 serum samples were obtained from wild swine caught in 41 prefectures in three fiscal years (April–March in 2014, 2015, and 2017) in Japan. Next, the seropositivity for ADV was evaluated using enzyme-linked immunosorbent assay and the latex agglutination and neutralization tests. Results showed that 29 swine were seropositive for ADV (29/1383, 2.1% [95% confidence interval, CI: 1.4%–3.0%]). Among them, 28 were caught in three prefectures located at the Kii Peninsula (28/121, 23.1% [95% CI: 16.0%–31.7%]). The degree of spatial clustering of ADV-seropositive adult swine at the Kii Peninsula according to sex was evaluated using K-function with the capture locations of 46 males including 14 seropositive and 54 females including 12 seropositive. In females, the degree of clustering was significantly higher in seropositive animals than in tested animals; however, such difference was not observed for seropositive males. Conclusions: The spatial dynamics of ADV among adult wild swine might be characterized based on sex. This finding might be attributed to sex-based differences in behavioral patterns including dispersal among wild swine.