Alphaherpesvirinae

Alphaherpesvirinae is a subfamily of the Herpesviridae family within the order Herpesvirales. It encompasses several genera, most notably Simplexvirus and Varicellovirus. Members of Simplexvirus include human herpes simplex virus 1 and 2; Varicellovirus includes varicella-zoster virus as well as a number of animal pathogens such as bovine herpesvirus 1 and pseudorabies virus. Alphaherpesvirinae viruses share a relatively short replication cycle, a broad epithelial and neuronal tropism, and a strong tendency to establish latent infections in sensory ganglia.

Viruses in this subfamily are enveloped, have icosahedral capsids, and possess linear double-stranded DNA genomes typically ranging from about 125 to 230 kilobases, encoding roughly 70 to 100 genes. They replicate in the cell nucleus and package their genomes through a tegument layer that interfaces with the host cell.

Biology and life cycle are characterized by efficient initial replication in mucosal or epithelial tissues, followed by spread to sensory neurons where the virus establishes latency in ganglia. Latent genomes persist with limited gene expression, and reactivation can occur under immunosuppression or stress, leading to recurrent disease manifestations.

Clinical and veterinary relevance is notable. In humans, herpes simplex viruses cause orofacial and genital lesions and ocular disease, while varicella-zoster virus causes varicella (chickenpox) and herpes zoster (shingles). Other alphaherpesviruses affect a wide range of animals. Vaccines exist for several alphaherpesvirus infections, including varicella and shingles in humans and various veterinary diseases.