[Study on ECHO virus 9 infections].

At Ste. Justine Hospital, Montreal, during the period 1957-61, ECHO 9 virus was isolated in 27 cases, in 20 of these during the summer of 1961. All had evidence of meningeal irritation, accompanied by fever and headache. Four of the 20 patients diagnosed during the summer of 1961 had convulsions; 12 presented with a rash; and two simulated meningococcemia. Of the 27 patients, two were paralyzed and one case was diagnosed as transverse myelitis. ECHO 9 virus was isolated from stools and from throat specimens in equal proportion; it was isolated from cerebrospinal fluid in only two instances. Pathogenicity for suckling mice was observed in two of 22 inoculated directly with the specimen material and in 10 of 11 inoculated with the cultured material.