Figure 4. Generalized virus lifecycle diagram.

Viral cell entry, replication, and dissemination are outlined, with the status of the host cell (light red) and virus membranes (dark red) highlighted throughout. The virus adheres to the cell surface, binding to host receptors, and is endocytosed, while the virus membrane remains intact. The virus membrane then fuses with the endosome membrane, often mediated by the same protein that is initially bound to the cell surface receptor. Virus and endosome membrane fusion admits viral entry to the cell cytoplasm, enabling replication and expression of the viral genome. Finally, virus surface proteins form a nascent structure within the cell membrane into which the viral genome is packaged, and the mature virion is released into the extracellular environment. Zika virus is used as a specific example.