Virological diagnosis of herpes simplex encephalitis

Abstract

Background: The herpes simplex encephalitis (HSE) represents one of the most severe infectious diseases of the central nervous system. As effective antiviral drugs are available, rapid and reliable diagnosis has become important.

Objectives: To evaluate retrospectively the usefulness of polymerase chain reaction (PCR) as well as serological procedures for the diagnosis of HSE.

Study design: 631 cerebrospinal fluids (CSF) from patients with clinical suspicion of encephalitis were tested for type-specific herpes simplex virus (HSV) DNA using PCR. Virus-specific antibodies including their intrathecal synthesis were measured in 624 CSF and 2409 serum samples of 2711 patients suspected of having encephalitis.

Results: Positive results were obtained by PCR in eight patients (1. 3%) for HSV-1 and in seven (1.1%) for HSV-2. Intrathecal antibody synthesis was estimated in 24 (3.8%) patients. In general, no intrathecal antibodies could be measured in patients with positive PCR results and vice versa the intrathecal immune response became positive when CSF was cleared from the HSV. Results of the antibody detection in serum specimens revealed an active HSV infection in 268 out of 2367 patients (11.3%).

Conclusions: The detection of HSV-DNA by PCR is the method of choice for diagnosis of HSE in the early phase of the disease. During the later stage, it has to be diagnosed by the estimation of intrathecally synthesized antibodies.