On external surfaces the virus is short lived, however it is extremely contagious. Most people acquire the virus via direct contact, it can enter the body by disrupting the integrity of skin, mucous membranes or enter via infected secretions such as saliva. The virus replicates once it has penetrated the epithelial cell, then it travels to the corresponding nerve ganglion (i.e. trigeminal ganglion) via sensory nerves endings. At the nerve ganglion the virus enters a latent phase and remains dormant until it is reactivated. Reactivation can be spontaneous or stimulated by a number of factors such as: reinfection by direct effect of stimuli, immunosuppression, ultraviolet light, febrile illnesses and stress.