herpesvirusen

Herpesviruses are a large family of enveloped DNA viruses in the order Herpesvirales. They have large linear double-stranded DNA genomes and share the ability to establish lifelong latent infections in host cells, with periodic reactivation. The family is divided into three subfamilies: Alphaherpesvirinae, Betaherpesvirinae, and Gammaherpesvirinae.

In humans, eight herpesviruses are commonly discussed: herpes simplex virus type 1 and 2 (HSV-1, HSV-2), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human herpesviruses 6, 7, and 8 (HHV-6, HHV-7, HHV-8). HSV-1 and HSV-2 cause oral and genital lesions, respectively; VZV causes varicella (chickenpox) and may reactivate as herpes zoster (shingles). EBV is associated with infectious mononucleosis and certain cancers; CMV can cause congenital disease and retinitis in immunocompromised individuals; HHV-6 and HHV-7 are common causes of roseola; HHV-8 is linked to Kaposi sarcoma.

Transmission occurs via close contact with secretions, saliva, or lesions, or through blood and organ transplantation. After initial infection, viruses establish latency in specific cell types (neurons for HSV and VZV; B cells for EBV; various hematopoietic cells for CMV) and can reactivate, sometimes with recurrent disease.

Diagnosis relies on molecular methods, serology, or viral culture. Treatments include nucleoside analog antivirals such as acyclovir, valacyclovir, and ganciclovir. Vaccines exist for varicella and for prevention of herpes zoster in older adults.