Cross-section of an iridovirus budded from a host cell, illustration. Iridoviruses are a family of viruses with a double-stranded deoxyribonucleic acid (DNA) genome. Their natural hosts include amphibians, fish, and invertebrates. Infected insects have a characteristic iridescent colour. Their structure consists of an outer icosahedral protein coat (capsid, pink), an intermediate lipid membrane, and a central DNA-protein core (orange). They may also gain an extra outer lipid layer (envelope, purple) when budding from infected cells.