abstract:Mardivirus is a recently established genus within the Alphaherpesvirinae subfamily. It is made up of the Marek's disease virus (MDV), which causes a lymphoproliferative disease in chickens, and two other closely related viruses including gallid herpesvirus 3 (GaHV-3 also known as MDV-2) and the herpesvirus of turkeys (HVT).