Coloured scanning electron micrograph (SEM) of melanoma skin cancer cells in the early stages of apoptosis caused by a viral infection. Apoptosis, or programmed cell death, of an infected host cell has been identified as a powerful mechanism to curtail viral spread, and consequently, viruses have evolved sophisticated molecular strategies to subvert host cell apoptotic defences. The cell becomes spherical as its cytoskeleton, which holds cell shape, is digested, and blebs form on its surface (as seen here). Eventually the cell breaks into several vesicles, now known as apoptotic bodies, and is phagocytosed (engulfed and digested) by specialist cells. Magnification: x4000 when printed at 10 centimetres wide