Epidemic of aseptic meningitis associated with ECHO virus type 9.
D004459:Echovirus 9; D058872:Epidemics; D008581:Meningitis / Q000453:epidemiology*; D008582:Meningitis, Aseptic; D014777:Virus Diseases / Q000453:epidemiology*
MENINGITIS/epidemiology; VIRUS DISEASES/epidemiology