Prototypic α-genus coronaviruses include human coronavirus NL63(HCoV-NL63), porcine transmissible gastroenteritis coronavirus (TGEV), and porcine respiratory coronavirus (PRCV). Prototypic β-genus coronaviruses include severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East Respiratory Syndrome coronavirus (MERS-CoV), mouse hepatitis coronavirus (MHV), and bovine coronavirus (BCoV). Prototypic γ-genus coronaviruses include avian infectious bronchitis virus (IBV).