Differentiation of herpes simplex virus 1 and 2 in cerebrospinal fluid of patients with HSV encephalitis and meningitis by stringent hybridization of PCR-amplified DNAs.

Differentiation of herpes simplex virus (HSV) types 1 and 2 in cerebrospinal fluid of 17 patients with serologically diagnosed HSV encephalitis and meningitis or acute limbic encephalitis was determined by stringent hybridization of polymerase chain reaction--amplified DNAs. Ten of 17 patients were positive; six with HSV 1 isolates and four with HSV 2 isolates. We detected HSV type 1 in two cases of meningitis, although meningitis is generally thought to be caused by type 2. Additionally, HSV type 2 was found in one case of acute adult encephalitis, which is generally due to HSV type 1. HSV DNAs could be detected for over 1 month after onset, although our patients included several prolonged and recurrent cases. HSV DNA genomes were not detected in three cases of acute limbic encephalitis. Our study indicates that this method can be used for type differentiation in HSV CNS infections.