Mumps or Coxsackie A9 virus antibody in the cerebrospinal fluid of patients with meningitis or encephalitis.

Ten patients with meningitis and one patient with encephalitis associated with mumps virus infection were studied and nine patients had mumps virus antibody in their cerebrospinal fluids taken 19-36 days after onset. Another 10 patients with meningitis associated with Coxsackie A9 virus infection were investigated and three patients had significant Coxsackie A9 virus antibody in their cerebrospinal fluids taken 14-20 days after onset. There was evidence that the mumps and Coxsackie A9 virus antibody in the cerebrospinal fluids was produced inside the central nervous system. In the acute and convalescent cerebrospinal fluids there was no correlation between the white blood cell counts and the mumps or Coxsackie A9 virus antibody titres.