Varicella zoster virus infection in neurological patients in Bulgaria.

The clinical manifestations of neurological complications associated with varicella zoster virus (VZV) are non-specific and indistinguishable from those of other viral infections. Therefore, the definite diagnosis requires evidence of VZV infection in cerebrospinal fluid (CSF). The aim of this study was to determine the frequency of VZV DNA detection in CSF of patients with neurological diseases in order to obtain information concerning involvement of VZV infection in neuropathology in the country. This study is a retrospective survey of test results obtained from January 2015 to October 2019. During this period, 411 CSF specimens were tested for the presence of VZV DNA by nested PCR. Fisher's exact test was used to test for statistically significant difference in the frequency of VZV DNA positivity of CSF specimens from different groups. Of all 411 tested CSF samples, 11.2% were positive for VZV DNA. The highest VZV prevalence was detected in CFS from patients with meningitis-18.2%, followed by patients with cranial neuritis (15.4%), encephalitis (12.2%), Guillain-Barré syndrome (11.1%), myelitis (10%), and with other neurological syndromes (8.2%). The difference of VZV prevalence in CSF of patients according to the gender and age was not statistically significant. Our results indicated that VZV is a frequent causative agent of neurological diseases, suggesting an important role of VZV infection for neuropathology in the country. Therefore, efforts for wider application of VZV identification in CSF to facilitate faster onset of antiviral treatment and further strategies concerning varicella zoster virus vaccines in the country are needed.