An ECHO (Enteric Cytopathic Human Orphan) virus, is a type of RNA virus and is found in the gastrointestinal tract. Exposure to the virus is usually harmless but may cause serious illness such as encephalitis, meningitis, heart and liver disease. The diameter of an echovirus is about 24-30 nanometres. The naked protein capsid shown in this illustration makes up 75% of the virus particle that encloses a dense central core of single-stranded RNA.

 

The structure of this virus illustration is based on cryo-electron microscopy and was solved by Prof. M.G.Rossmann et al. The data set included the atomic coordinates of the C-alpha atoms but not those of the amino acid side chains. This is the reason for the 'worm/brain'-like surface structure of this illustration.