Outbreak of Porcine Reproductive and Respiratory Syndrome Virus 1 in Taiwan

Porcine reproductive and respiratory syndrome (PRRS) causes significant economic lossesin the swine industry worldwide. The PRRS virus (PRRSV) can be divided into two species, PRRSV1 (European) and PRRSV 2 (North American). In Taiwan, PRRSV 2 isolates are dominant and causerespiratory symptoms in nursing pigs. From October to November 2018, in a pig herd in centralTaiwan, pregnant sows had abortions and stillbirths, and piglets suffered from respiratorydisorders. Laboratory tests identified the presence of PRRSV 1 in serum from sows and sucklingpiglets in this scenario. The complete genome of the identified PRRSV 1 strain was geneticallyclosely related to that of a European PRRSV vaccine strain (98.2%). This local European isolate isdesignated as PRRSV/NPUST-2789-3W-2/TW/2018 (NPUST2789). This report is the first to indicatean outbreak in Taiwan of a PRRSV 1 strain that shares a common evolutionary ancestor with theEuropean PRRSV vaccine strain.