Herpes Consensus PCR test: a useful diagnostic approach to the screening of viral diseases of the central nervous system.
BACKGROUND
Infections of the central nervous system (CNS) are a difficult diagnostic problem for both clinicians and microbiologists. Various clinical signs, such as encephalitis, myelitis, meningitis, may be associated with herpesviruses. The use of multiplex 'Herpes Consensus' polymerase chain reaction (HC-PCR) in association with nested PCR (nPCR), in addition to classical techniques, made it possible to optimise the management of cerebrospinal fluid (CSF) and serum samples from patients affected by these viral diseases of the CNS.


OBJECTIVE
To test by HC-PCR by nPCR and cell culture the CSF and sera from patients with viral infections of the CNS.


METHODS
We analysed 320 CFS, 154 serum samples and 11 various samples from 286 patients with clinically suspected encephalitis, meningitis or other diseases of the CNS by HC-PCR, nPCR and traditional investigations (cell culture and serological tests).


RESULTS
On molecular analysis with the HC-PCR test, 51 CFS samples (15.9%) were positive for at least one of the six target Herpes viruses: fourteen for Herpes simplex 1 (HSV-1), seven for HSV-2, 12 for Cytomegalovirus (CMV; one of which was from an HIV-positive patient), five for Epstein-Barr virus (EBV; four of which were from HIV-positive patients), three for Varicella-Zoster virus (VZV), five for Human Herpes virus type 6 (HHV-6), three for HSV-1 with HHV-6 co-infection (two cases) and HSV-2 co-infection (one case), and two for HHV-6 with CMV or EBV co-infection (both from patients with immune deficiency). A further 12 samples were positive in nPCR for HHV-7 (8), ADV (1), Enterovirus (1), HSV-1 (1), EBV (1). Of the 154 serum samples, 17 (11.0%) tested positive by HC-PCR for HSV-1 (4), HSV-2 (1), CMV(1), EBV(1), VZV(3) or HHV-6(6), 1 with co-HSV-2/VZV infection. A further five samples tested positive for HHV-7 in nPCR. Culture and tests for antibodies did not supply sufficiently sensitive and specific data.


CONCLUSIONS
Our laboratory experience shows that herpesviruses play a central aetiological role in viral infections of the CNS. PCR analysis, especially the HC-PCR test, have revolutionised the diagnostic approach to such infections, making possible rapid, specific and highly sensitive baseline screening. In this way, microbiological investigations can lead to prompt diagnosis, which was limited in the past to a very small number of cases.
Calvario
A
A
Virology Laboratory, Hygiene, Epidemiology and Public Health Department, Policlinico, P.za G. Cesare, 11-70124 Bari, Italy. m.quarto@igiene.uniba.it
Bozzi
A
A
Scarasciulli
M
M
Ventola
C
C
Seccia
R
R
Stomati
D
D
Brancasi
B
B
D000914:Antibodies, Viral / Q000032:analysis; D020805:Central Nervous System Viral Diseases / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D004279:DNA, Viral / Q000032:analysis; D006564:Herpesviridae / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D006566:Herpesviridae Infections / Q000097:blood / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D011786:Quality Control; D011933:Reagent Kits, Diagnostic; D014776:Virus Cultivation
D000914:Antibodies, Viral; D004279:DNA, Viral; D011933:Reagent Kits, Diagnostic