Detection and typing of human herpes virus 6 by molecular methods, in specimens from patients diagnosed with encephalitis/meningitis
Wadsworth Center, New York State Department of Health, Albany NY, and School of Public Health, SUNY Albany, Albany, NY
ABSTRACT
Human herpesvirus-6 (HHV-6) was detected in specimens from patients hospitalized with symptoms of encephalitis or meningitis. A real-time PCR assay was developed which has a linear dynamic range of 5 to 5 x 106 copies of HHV-6 and a sensitivity of 5 gene copies per reaction. While the assay detects both subtypes HHV-6A and HHV-6B, it is specific and does not cross-react with a selected specificity panel. A total of 1,482 patient specimens, which were collected between 2003 and 2007, were tested; 26 specimens from 24 patients were found to be positive by real-time PCR for HHV-6. The HHV-6 detection rate in this population was therefore 1.75%. The majority of the specimens tested (>95%) were cerebrospinal fluid (CSF) specimens. We were able to type 20 of the 26 positive specimens by conventional PCR and sequence analysis; all were HHV-6B. 42% of the patients were ≤3 years of age, which may indicate a primary infection in these patients. Given the ages of the remaining patients (from 4 to 81), their infections were most probably due to virus reactivation. Where information was available, symptoms of patients included fever (71%), altered mental status (67%), and, abnormal CSF profile (75%). 50% of patients ≤3 years of age suffered from seizures. The detection of HHV-6 in specimens from patients diagnosed with encephalitis or meningitis, in the absence of a positive PCR result for other agents, strongly suggests a role for HHV-6 in pathogenesis of these central nervous system diseases J. Clin. Microbiol. doi:10.1128/JCM.01692-07
