Viral necrosis. Coloured scanning electron micrograph (SEM) of a cultured Hela cancer cell which has become necrotic after infection with the rhinovirus virus. In addition to inducing immune and inflammatory responses, infection by most viruses triggers necrosis or apoptosis (programmed cell death) of the infected cell. Morphologically at SEM level, necrotic cells characteristically display ruptured plasma membrane, and cell lysis. The numerous visible holes are characteristic of early necrosis. Rhinoviruses (RVs) are the most common cause of the common cold. They chiefly cause upper respiratory tract infections (URTIs) but may infect the lower respiratory tract. Potential complications of infection include otitis media, sinusitis, chronic bronchitis, and asthma. Mag: x8000 when printed at 10 centimetres wide. Specimen courtesy of Virology Research Services Ltd (Scott Lawrence).