The herpes virus infects the humans to cause chickenpox disease. The virus during its stage of causing infection, it spreads through the epidermal cells by infecting them. This causes the typical rash on skin that is seen in chickenpox. The virus then enters that sensory nerves present on the ski and travels along the length of the neurons to the sensory dorsal-root ganglia adjacent to the spinal cord. Here the virus stays in an inactive stage.