Illustration of a rotavirus with a complete half and a cross-sectioned half revealing its inner structure. The RNA (ribonucleic acid) in the centre of the virus is double-stranded and consists of 11 segments. It is well protected by an icosahedral capsid that consists of three layers. The inner layer of VP2-proteins is made of protein dimers, the mid layer is made of VP6 proteins forming trimers and the outer layer consists of VP7 protein trimers. Protruding like spikes from the surface are several VP4-trimer-proteins, which consist of VP5 and VP8-protein subunits.