Human Herpes virus 3 (HHV3) or Herpes zoster virus or Varicella zoster virus (VZV) is the causative factor for herpes zoster infection.
The primary infection of Shingles (Herpes Zoster) causes varicella, i.e. chickenpox.
The virus remains hidden and dormant in the dorsal root ganglia of the spinal cord.
Reactivation of the virus later in life causes painful, maculopapular eruptions over a single dermatome or two or more contagious dermatomes resulting in herpes zoster infection.