Sehyeong Ham

1 Introduction Porcine circovirus 2 (PCV2) is a small (17–22 nm in diameter), nonenveloped single-stranded circular DNA virus that still causes an enormous economic impact on the pig industry (Chae 2005; Lv et al. 2014; Tischer et al. 1982). PCV2 is associated with several syndromes and diseases, collectively referred to as porcine circovirus-associated diseases (PCVAD) in Asia and North America, and porcine circovirus disease (PCVD) in Europe (Chae 2005; Segalés 2012).

1. Introduction Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically significant viral diseases and is present in most pig producing countries worldwide. Breeding age pigs are predisposed to the reproductive syndrome, while younger pigs and piglets typically experience the respiratory form of the disease [1]. The causative virus, PRRS virus (PRRSV), is an RNA virus belonging to the family Arteriviridae, now classified into the genus Porartevirus [2].

1 INTRODUCTION Porcine reproductive and respiratory syndrome (PRRS) continues to threaten the global swine industry resulting in enormous economic losses. PRRS virus (PRRSV), the etiological agent of PRRS, causes reproductive failures in sows and respiratory distress in pigs of all ages (Zimmerman et al., 2019).