envelopedviruses

Enveloped viruses are viruses that acquire a lipid envelope from the host cell membrane during budding from the cell. The envelope surrounds a nucleocapsid that contains the viral genome. The envelope bears viral glycoproteins that mediate attachment to host cell receptors and membrane fusion, enabling entry. The genomes can be DNA or RNA, either single-stranded or double-stranded, and include positive-sense, negative-sense, and retroviral reverse-transcribed forms. The replication strategy depends on the genome type: DNA viruses often replicate in the nucleus; RNA viruses generally replicate in the cytoplasm.

Enveloped viruses are typically less stable in the environment than nonenveloped viruses and are more susceptible to desiccation, heat, and detergents. They are commonly transmitted through respiratory droplets, bodily fluids, sexual contact, or blood; vector-borne enveloped viruses also exist.

Enveloped families include Herpesviridae, Poxviridae, Orthomyxoviridae, Coronaviridae, Flaviviridae, Filoviridae, Retroviridae, and Togaviridae. Notable members include herpes simplex virus, influenza virus, HIV, SARS-CoV-2, Ebola virus, dengue virus, and vaccinia virus. The envelope is a major target of the immune response; neutralizing antibodies often recognize envelope glycoproteins. Vaccines and antivirals frequently exploit this feature.