Aseptic meningitis, Montreal, 1969: a clinical and laboratory study.

During the summer and fall of 1969 an outbreak of aseptic meningitis occurred in Montreal and its environs. Forty-four patients were admitted to the infectious disease ward of The Montreal Children's Hospital in August, September and October. Half of the patients were in the age group 6 to 10 years. The ratio of males to females was two to one. Patients showed the typical signs and symptoms of aseptic meningitis, namely fever, vomiting, headache, neck stiffness and pleocytosis of the cerebrospinal fluid.Viruses were recovered from 19 (43%) of the 44 cases. The predominant virus in the outbreak was a non-hemagglutinating strain of echovirus 6. Other virus types isolated in the outbreak were echovirus 7, coxsackievirus A9 and coxsackievirus B4. Serological investigations confirmed the validity of the echovirus isolations and identified additional cases.