What is an enterovirus?
Human enteroviruses are a genus in the family Picornaviridae (small positive-sense single-stranded RNA viruses) that were originally classified or named as polioviruses, Coxsackie A viruses, Coxsackie B viruses, echoviruses, and enteroviruses. Rhinoviruses are included as enteroviruses by many researchers but not all. There are well over 100 types of known enteroviruses (genus Enterovirus). The virus that causes hand, foot, and mouth disease belongs to the group of so-called non-polio enteroviruses.
These enteroviruses usually spread from person to person by direct contact with the viruses that shed from the gastrointestinal tract or upper respiratory tract. In general, health care providers categorize these viruses as either polio or non-polioviruses. Polioviruses (only three types, P1-3) and non-polioviruses may have similar initial symptoms. In the majority of infections caused by both polio and non-polioviruses, an infected person may be asymptomatic (not show any symptoms) or only have mild symptoms, including fever, headache, sore throat, loss of appetite, and abdominal discomfort that resolves with no sequelae (complications). However, in some patients, especially children, these infections may cause serious disease that may produce lifelong problems and, infrequently, may cause death.
Recently, non-enterovirus species names were revised to remove host names (human, bovine, simian, and porcine) and replaced with the group designation (A through J) and serotype number. The group is based on the similarity within the RNA region that codes for the outer protein of the virus, and serotype number corresponds to a specific neutralizing serum (antibody). Consequently, human enterovirus 68, for example (also called HEV-68 and ED68) is now termed EV-D68. There will be confusion and overlap of enterovirus names for the next few years as researchers and clinicians adjust to this extensive name change. In this article, both new and currently accepted names of these viruses and the disease(s) they may cause will be used. For example, Coxsackie viruses could be labeled CV-A4 or CV-B5, depending on their group and/or serotype; similarly, echovirus=E-14 or rhinovirus=RV-A25, RV-B79, or RV-C41.