Identified ECHO type 6 virus as the etiological agent in an outbreak of seasonal aseptic meningitis that clinically resembled preparalytic poliomyelitis.
• Symptoms of aseptic meningitis occurred in 17 children and in 7 young adults out of 500 inhabitants of a village in July, 1955. Seven boys were hospitalized, and all had fever, headache, signs of meningeal irritation, and gastrointestinal complaints. Pain, lethargy, mild muscular weakness, and altered reflexes were present in some cases. Improvement was rapid, and all patients were discharged well, within 3 to 10 days, with no residual findings except occasional slight muscular weaknesses and minimal hamstring spasm. Laboratory observations included detailed virus studies of the cerebrospinal fluid, blood, throat swabs, and fecal specimens. No rise of poliovirus neutralizing antibody was demonstrable in any of the patients, but in all there were rises in circulating antibody to ECHO (enteric cytopathogenic human orphan) type 6 virus. Specific antibody appeared on the fifth day of illness and was still present after seven months, when the only residual finding was absence of the abdominal reflexes in two patients. The virus was isolated, and evidence of its etiological role is given. The disease could not be distinguished clinically from preparalytic poliomyelitis when the patients were admitted to the hospital. There are indications that epidemics of this kind are not unusual or isolated occurrences.
David T. Karzon (Sat,) studied this question.