AN OUTBREAK OF ASEPTIC MENINGITIS DUE TO ECHO 25 VIRUS.

In a widespread outbreak of aseptic meningitis during the summer and early fall of 1961 in Ontario, Echo type 25 virus was found to be the predominant virus type isolated from affected patients. Recovery of Echo 25 virus in several cases from the CSF of patients strongly suggests an etiological relationship between this virus type and the illness. The causative role of the virus was confirmed by demonstration of significant immunological response in patients found to be infected with the virus. The presence of antibodies to Echo 25 virus in about 70% of meningitis patients, from whom no virus was isolated, indicates that the infection in the population of the affected areas was much more prevalent than the number of successful virus isolations would suggest. It is recommended that Echo 25 virus should be added to the series of Echo virus types capable of causing outbreaks of aseptic meningitis.