Enteroviruses are a group of viruses that contain ribonucleic acid as their genetic material. They are members of the picornavirus family. The various types of enteroviruses that infect humans are referred to as serotypes, in recognition of their different antigenic patterns. The different immune response is important, as infection with one type of enterovirus does not necessarily confer protection to infection by a different type of enterovirus. There are 64 different enterovirus serotypes. The serotypes include polio viruses, coxsackie A and B viruses, echoviruses and a large number of what are referred to as non-polio enteroviruses.

The genetic material is enclosed in a shell that has 20 equilateral triangles (an icosahedral virus). The shell is made up of four proteins.

Despite the diversity in the antigenic types of enterovirus, the majority of enterovirus cases in the United States is due to echoviruses and Coxsackie B viruses. The infections...