Detection of Herpes Simplex Virus in Cerebrospinal Fluid Using Real-Time PCR

Herpes simplex virus (HSV) is the most common, recognized cause of sporadic and severe encephalitis in the USA. The virus is estimated to account for at least 10–20 % of all viral encephalitis occurring in patients of all ages [30, 32, 57]. It is also important to underscore the worldwide impact of HSV infections in patients with superficial and systemic disease within every major organ system in both normal and immunocompromised hosts. Furthermore, this virus is usually the most frequent agent recovered in diagnostic laboratories from a variety of specimens using conventional (tube cell cultures) and rapid shell vial culture methods [18, 47]. Approximately 90 % of adults are seropositive for HSV, which is consistent with studies showing the detection of the viral genome in the trigeminal ganglia of 85–95 % of unselected autopsy cases [25]. Despite the high seroprevalence of HSV, the virus is rarely recovered from cerebrospinal fluid (CSF) specimens in viral culture, and this has been a major technical obstacle for the diagnosis of central nervous system (CNS) disease caused by this virus. Of 425 viral isolates recovered from CSF at the Mayo Clinic over a 12-year period (1984–1996), only 9 (2 %) were HSV [52].