Polymerase chain reaction (PCR) was prospectively performed with cerebrospinal fluid (CSF) from 51 patients whose CSF was available for analysis and was submitted for viral culture and/or herpes simplex virus (HSV) serology and 20 patients whose CSF was submitted exclusively to the Clinical Biochemistry Laboratory. Primers were used that flanked a 92 bp segment of the HSV
DNA polymerase gene (35 cycles). Amplified products were electrophoresed on
agarose gel, blotted onto
nylon membrane, and probed with a 32P-labelled sequence internal to the primers. For nested PCR, 1 microliter of PCR product was amplified for an additional 35 cycles before electrophoresis and Southern blot analysis. Review of the clinical records revealed that 15 patients had central nervous system (
CNS) infections. Specific HSV DNA sequences were detected in CSF specimens of three of the individuals [PCR(2), nested PCR(1)]. Two of these patients had disseminated HSV
infection including
encephalitis and one patient had
aseptic meningitis. The diagnoses of the 12 patients with
CNS infection who did not have HSV
DNA detected in CSF included
encephalitis [varicella-zoster virus (1), cytomegalovirus (1), Mycoplasma pneumoniae (1)],
meningitis [Neisseria meningitidis (1), Coccidioides immitis (1), Enterovirus (1),
aseptic meningitis (1)],
varicella-
zoster radiculitis (2), human immunodeficiency virus
dementia (2), and
transverse myelitis due to Epstein-Barr virus (1). Importantly, HSV
DNA was also not detected in the CSF of the 36 patients who did not have
CNS infection and 20 samples submitted exclusively to the Clinical Biochemistry Laboratory. Our findings demonstrate the utility of PCR as a rapid, non-invasive method for the routine laboratory diagnosis of
CNS infection due to HSV.