premise: Marek's disease is caused by an alphaherpesvirus known as 'Marek's disease virus' (MDV) or "Gallid herpesvirus 2" (GaHV-2).
hypothesis: Marek 's disease is caused by an alphaherpesvirus known as ' Marek 's disease virus ' MDV Gallid herpesvirus 2 " GaHV-2.