A 22 year old male military recruit complains of a headache and stiff neck. He is examined, blood is drawn, and a lumbar puncture performed. The glucose in the CSF is 100 mg/dL and the serum glucose is 120 mg/dL. The CSF shows 3 lymphocytes and 0 neutrophils/microliter. Which of the following conclusions concerning the interpretation of these findings is most accurate?