any of a group of enteroviruses that includes viruses which cause mild forms of meningitis, gastroenteritis, etc., and others which appear to be asymptomatic
See echovirus in American Heritage Dictionary 4
nounpl.ech·o·vi·rus·es
Any of a number of enteroviruses of the family Picornaviridae, inhabiting the gastrointestinal tract and associated with various diseases, such as viral meningitis, mild respiratory infections, and severe diarrhea in newborns.