Herpesviruses and enteroviruses in infections of the central nervous system: a study using time-resolved fluorometry PCR.
BACKGROUND: Polymerase chain reaction (PCR) is becoming the new standard for virological diagnosis of the infections of the central nervous system (CNS). Varicella-zoster virus (VZV) has been considered as the leading cause of viral meningitis or encephalitis in Finland, herpes simplex viruses (HSV) and enteroviruses being the next common causative agents. OBJECTIVES: To elucidate the roles of viruses in infections of the CNS by use of novel, sensitive time-resolved fluorescence (TRF) PCR assays. STUDY DESIGN: We have utilized TRF PCR assays for diagnostics of HSV, VZV, human cytomegalovirus (CMV) and enteroviruses in infections of the CNS. When relevant, we have also applied virus culture and CSF IgM antibody determinations to elucidate the involvement of other viruses in the CNS infections. The material consisted of CSF samples from hospitals in Western Finland, submitted for diagnostic testing for CNS viral infections during the years 2000-2001. A total of 922 CSF samples were tested by PCR. RESULTS: The PCR assays yielded the virological diagnosis in 72 cases whereas only 24 samples were positive by virus culture or CSF IgM antibody assays. Enteroviruses were found in 6.8%, VZV in 5.8% and HSV in 4.6% of the studied CSF samples. The virus culture and CSF antibody tests yielded 0.5-3.2% positive findings. CONCLUSIONS: The PCR assays of CSF specimens are most effective for the virological diagnosis of CNS infections. In our study, HSV was the most common causative agent, whereas the diagnostic power of TRF-PCR test was highest for enteroviruses.