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Journal of Clinical Microbiology, August 2005, p. 4172-4174, Vol. 43, No. 8
0095-1137/05/$08.00+0 doi:10.1128/JCM.43.8.4172-4174.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
Prevalence of Herpes Simplex Virus (Types 1 and 2), Varicella-Zoster Virus, Cytomegalovirus, and Human Herpesvirus 6 and 7 DNA in Cerebrospinal Fluid of Middle Eastern Patients with Encephalitis
Ali I. Ibrahim,1
Michel T. Obeid,1
Muhidien J. Jouma,1
Klaus Roemer,2
Nikolaus Mueller-Lantzsch,2 and
Barbara C. Gärtner2*
Department of Clinical Chemistry and Microbiology, University of Damascus, Syria,1
Department of Virology, University of Saarland Medical School, Homburg/Saar, Germany2
Received 31 March 2005/
Returned for modification 10 May 2005/
Accepted 14 May 2005

ABSTRACT
HSV-1 DNA was detected in 32 (30%) of 106 cerebrospinal fluid
samples from patients with encephalitis. Cytomegalovirus, varicella-zoster
virus, and human herpesvirus 6 (HHV-6) DNAs were each detected
in three patients (3%); herpes simplex virus type 2 (HSV-2)
and HHV-7 PCRs were negative. HSV detection was associated with
seizure (
P = 0.02), especially focal seizure (
P = 0.0002), and
pathological computed tomography (
P = 0.02) with focal lesions
(
P = 0.0004).

TEXT
Herpesviruses, especially herpes simplex virus (HSV), varicella-zoster
virus (VZV), and human herpesvirus 6 (HHV-6), play a major role
as a cause of meningitis or encephalitis (
8,
9,
13). Viral encephalitis
is associated with significant mortality and morbidity, and
its outcome is directly correlated with the rapid onset of antiviral
therapy (
12,
15). Therefore, the appropriate management of encephalitis
needs techniques suitable for a rapid diagnosis, such as PCR
(
1,
10).
The aims of this study were to evaluate the prevalences of HSV-1, HSV-2, VZV, cytomegalovirus (CMV), HHV-6, and HHV-7 in cerebrospinal fluid (CSF) samples from Middle Eastern patients with encephalitis or meningitis, as well as in controls, and to correlate virus detection with clinical symptoms.
CSF was obtained from 106 patients with encephalitis and 11 patients with meningitis, and the patients had a mean age of 4 years (1 month to 40 years). Sixty-one samples (52%) were taken 1 to 5 days after the onset of symptoms, 33 samples (28%) were taken 6 to 10 days after symptom onset, and 23 samples (22%) were taken after 11 days after symptom onset. Patients were considered to have meningitis when at least one of the following symptoms was present and other causes were ruled out: nuchal rigidity, Kernig's sign, Brudzinski's sign, and Lasegue's sign. Encephalitis was suspected when an altered level of consciousness or significant change in personality or cognitive dysfunction or focal neurological symptoms not explained by cranial nerve paralysis persisted for
24 h and other causes were excluded. In all patients, the disease was accompanied by at least two of the following symptoms: headache, nausea, temperature of
38°C, and pleocytosis (>5 white blood cells/µl CSF). As controls, 35 patients (mean age, 2 years [2 months to 12 years]) with noninfectious neurological disorders or with infectious but nonneurological diseases were enrolled.
DNA was extracted by use of the QIAamp tissue kit (QIAGEN, Hilden, Germany) according to the manufacturer's instructions. DNA was detected by a hot-start real-time PCR on the LightCycler instrument (Roche, Mannheim, Germany), as previously described in detail for HSV-1, HSV-2, and CMV (5). For VZV, HHV-6, and HHV-7 PCRs, a similar PCR was performed using the following primers and probes: for HHV-6, primers 5'GCTTTTCTAGCCGCCTCTTC3' and 5'CCACATCTATAATTTTAGACGATCCC3', fluorescein probe 5' CCATATCTACAAAACTTAGGTGCTGGGTGA3', and Red640 probe 5'GTTGTAAGTGGTTGCGATATCTTTAGCTTCC3'; for HHV-7, primers 5'TATCCCAGCTGTTTTCATATAGTAAC3' and 5'TTGCGGTAGCACTAGATTTTTTG3', fluorescein probe 5'CATTTGTACTTCAAAGTAGCCTTCATTAGGATAGCT3', and Red640 probe 5'GACACCAACATCTGTCTATCATTTCTGGATGAA3'; and for VZV, primers 5'TTGAGGAAGTTGAAGCCAGATCA3' and 5'TCCAGTTCCAACCAACCGTTA3', fluorescein probe 5'TGAAAACGATCCATTGCATAATTGGAAT3', and Red640 probe 5'TTCTCTGTATGCACCATCCCGTAGG3'. Annealing temperature was 64°C for VZV and HHV-6 and 61°C for HHV-7. Inhibition and extraction control was performed by a second extraction and PCR with the same sample spiked with positive control before extraction. Statistical analysis was done by Fisher's exact test and the Mann-Whitney U test.
HSV-1 DNA was detected in 32 patients out of 106 with encephalitis (30%); none of the patients with meningitis alone was HSV DNA positive. Other herpesviruses were present at a much lower rate. VZV DNA was detected in three patients (3%) with encephalitis and in one with meningitis (9%). DNAs of CMV and HHV-6 were each found exclusively in three patients with encephalitis (3%). HSV-2 and HHV-7 were not detectable. Double infections were found in two patients (HSV/CMV and HSV/HHV-6). Together, herpesviral DNA was found in 39 patients (37%) with encephalitis and at a much lower frequency in patients with meningitis (1 patient, 9%). By contrast, all 35 samples of the control group were negative. When the sampling time was taken into consideration, the rate of PCR-positive samples was highest within days 6 through 10 after the onset of symptoms (48%). Sampling at days 1 to 5 revealed a much lower rate (25%) (P = 0.02), as did sampling >10 days after the onset of symptoms (35%).
To identify historical, clinical, and laboratory abnormalities associated with herpes simplex-positive encephalitis, the data from the 32 patients with HSV DNA in CSF were compared with those of 74 HSV-negative patients with encephalitis (Table 1). The clinical presentations differed significantly only in the numbers of patients with seizures (P = 0.02) and in particular, seizures of the focal type (P = 0.0002). This is also reflected by the higher number of pathological computed tomography scans (P = 0.02), and again, the focal appearance of lesions (P = 0.0004). In addition, the outcome of the encephalitis was worse in patients with HSV-1 encephalitis. All other clinical, historical, and laboratory data were not significantly different.
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TABLE 1. Historical, clinical and neurodiagnostic data of 32 HSV-1 PCR-positive patients compared to 74 HSV-1 PCR-negative patients, both groups with encephalitis
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The present study covered mainly pediatric patients from Syria.
Herpesviral DNA was strongly predominant (37% in patients with
encephalitis). HSV encephalitis is known to occur at any age;
however, it has a bimodal distribution, with one-third occurring
at an age of less than 20 years (
14). The prevalence of HSV-1
is high in Syria, reaching 80% even at a young age of 6 to 10
years (
6), explaining the elevated numbers of HSV encephalitis
in these pediatric patients. The failure to identify HSV-2 likewise
reflects the epidemiology of rarely seen HSV-2 infections in
Syria (
6). Although HHV-6 und CMV are known to cause encephalitis
in rare cases (
7,
11), it cannot be excluded that contamination
by leukocytes may account for the few PCR-positive subjects.
Of note in this context, HHV-6 genome and antigens are frequently
detected in patients with multiple sclerosis, suggesting that
the virus may persist in brain tissue even without causing encephalitis
(
2). The low prevalence of VZV in CSF is most likely reflected
by the very low number of patients with symptoms compatible
with chickenpox or herpes zoster (two patients, 2%).
Importantly, several investigators have reported patients with HSV encephalitis that were negative by CSF PCR (1, 4, 10). Obviously, different factors, including the time of sampling of the CSF specimens, may be critical. We have observed that HSV DNA may be more readily detectable in the later phases after the onset of symptoms and not in the very acute phases, in accord with earlier reports (1, 3). It might be speculated that especially focal lesions in the very early course do not necessarily result in viral DNA in CSF.
In conclusion, we have identified HSV-1 as an important agent of viral encephalitis in mainly pediatric patients from Syria, whereas VZV, CMV, and HHV-6 were rarely seen, and the two herpesviruses HSV-2 and HHV-7 were never detected. Seizures of the focal type and focal lesions in the computed tomography scan were significantly more frequently associated with PCR-established HSV encephalitis than with DNA-negative encephalitis.

ACKNOWLEDGMENTS
We thank the technicians Helga Appel, Iris Kaffenberger, and
Christine Karrenbauer for their invaluable assistance.

FOOTNOTES
* Corresponding author. Mailing address: University of Saarland Medical School, Department of Virology, Haus 47, D-66421 Homburg/Saar, Germany. Phone: 49 6841 1623950. Fax: 49 6841 1623980. E-mail:
vibgae{at}uniklinik-saarland.de.


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Journal of Clinical Microbiology, August 2005, p. 4172-4174, Vol. 43, No. 8
0095-1137/05/$08.00+0 doi:10.1128/JCM.43.8.4172-4174.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
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