A serological survey of porcine reproductive and respiratory syndrome virus in wild boar in Gifu Prefecture, Japan

Porcine reproductive and respiratory syndrome (PRRS) is an infectious swine disease caused by the PRRS virus (PRRSV) that results in economic loss to the pig-rearing industry. To study PRRSV infection in wild boars and pigs, we conducted a serological survey in Gifu Prefecture, Japan, from 2020 to 2021. Three out of 453 (0.7%) wild boar sera were positive for PRRSV antibodies in a commercial ELISA. However, given that PRRSV RNA was not detected in these three wild boars and the specificity and sensitivity of the test kit, these are considered as false positives. Although seropositive pigs were found in multiple pig farms in the study area, the role of wild boars as a source of PRRS to pig farms appeared to be minimal.