The round trip model for severe herpes zoster caused by live attenuated varicella vaccine virus

: The neurovirulence of the live attenuated varicella vaccine virus is a subject of increasing interest. Since there is no ideal animal model for varicella-zoster virus (VZV) infection and neuropathogenesis, we have turned to animal models for the closely related pseudorabies virus (PRV). PRV is the alpha herpes virus of swine; the first live attenuated PRV vaccine (Bartha strain) was produced in 1961 in Hungary, a decade before the live attenuated VZV vaccine (Oka strain) was produced in Japan. Neurologic disease caused by PRV often resembles neurologic disease caused by VZV. Unlike VZV, PRV replicates in other mammals, such as the dog and rodents. When PRV infects these animals, PRV causes a disease called "mad itch," a virulent pruritis. Depending on the site of PRV entry into the scarified skin of the mouse model, within 2 days mice will unceasingly scratch the skin adjacent to the site of infection, which leads to a circumscribed lesion precisely defining the dermatome of the innervating dorsal root ganglion (DRG). Infection of the DRG is necessary for the occurrence of mad itch. This article is protected by copyright. All rights reserved.