Enteroviruses, such as enterovirus 71, are classified to be in the picornavirus family, pico [small] + RNA [ribonucleic acid] + virus. Picornaviruses are among the smallest and simplest ribonucleic acid containing viruses known (1). The RNA for many enteroviruses have now been cloned and complete genomic sequences have been obtained. The RNA from all sequenced enteroviruses are similar in length, about 7400 nucleotides, and have identical organization (1). 
   The human alimentary tract is the predominant site of enterovirus replication and these viruses were first isolated from enteric specimens. These viruses are the cause of paralytic poliomyelitis, aseptic meningitis-encephalitis, myocarditis, pleurodynia, hand-foot-and-mouth disease, conjunctivitis, and numerous other syndromes associated with extra-intestinal target organs. There are 67 numbered types of enteroviruses in the enterovirus family (1): three polioviruses, twenty-three coxsackieviruses A, six coxsackieviruses B, thirty-one echoviruses, and four other enteroviruses.