Inclusion Criteria:  Residual specimens (minimum 500μL) of CSF obtained by lumbar puncture from subjects with signs and symptoms of meningitis and/or encephalitis following completion of routine testing Specimen that have not undergone more than 3 freeze/thaw cycles.  Exclusion Criteria:  Specimens not fitting criteria outlined above. CSF obtained from an external ventricular drain or shunt source. Lack of clear subject identification or label on residual banked CSF specimen. Specimen has been centrifuged. Obvious physical damage of banked residual specimen. Repeat specimens from the same subject.