The Virus
The varicella-zoster virus (Human Herpesvirus 3) is a DNA virus belonging to the Herpesviridae family, the Alphaherpesvirinae subfamily and the Varicellovirus genus. Varicella and zoster represent different clinical manifestations of the same infective agent, the VZV.
Clinical manifestations
Varicella is the primary infection of VZV and it mainly occurs in children. It’s characterized by a vesicular exanthema, which is often associated to fever. Zoster is a secondary infection provoked by the reactivation of latent VZV in nervous ganglion: it occurs in old people or in immune-depressed and it consists in vesicular cutaneous eruption with nervous sensory ganglion inflammation. Sun or stress can help the reactivation of VZV.
Prevention
A soft vaccine with VZV is available and it’s recommended to patients who have an high risk of problematic progress of the illness (children with serious tumors before immune-depressive therapies). A passive immunisation is possible with VZV immunoglobulin for not immune people, which are at contact with the virus.
Epidemiology
Varicella is a childhood illness at high risk of contagious (90%), the 90% of teenagers have antibodies against the virus. The incubation period of the varicella is about 2-3 weeks and it’s contagious 1-2 days (maximal 5) before the appearance of vesicles and up to 6 days after the appearance.
Test
Highlight of the virus through PCR.
Sample taking
Eye and vesicular smear, liquor and biopsy.
