Abstract

Human herpes virus (HHV) infection of the central nervous system (CNS) is a common problem worldwide. The incidence of HHV-CNS infection in human immunodeficiency virus/ acquired immunodeficiency syndrome (HIV/AIDS) patients and non-HIV patients has been studied at Rajavithi Hospital, Bangkok, Thailand. To identify the prevalence and incidence of HHV1 (HSV), HHV3 (VZV), HHV4 (EBV), HHV5 (CMV), HHV6A,B, and HHV 7-CNS infection, and to differentiate the clinical manifestations, laboratory findings between HSV-encephalitis and non-HSV/HHV-CNS infection amongst patients at Rajavithi Hospital, Bangkok, Thailand. An 18-month prospective study of patients with clinically suspected CNS infection was enrolled. Cerebrospinal fluid (CSF) examination and culture, along with real time polymerase chain reaction (RT-PCR) for HSV-1, HHV3, HHV4, HHV5, HHV6, HHV7 and Mycobacteriumtuberculosis were performed. Criteria for diagnosis of HHV-CNS infection included fever, headache, seizure, alteration of consciousness, neurological localizing signs and/or neck stiffness. A total of 94 patients, 52 male and 42 female, aged between 16 - 77 years (mean + SD = 42.3 + 14.5) were enrolled between July 2008 - December 2009. Forty four patients were confirmed to be HIV/AIDS positive. Of this, 27% were treated with highly active antiretroviral treatment (HAART). There was significant difference of age and gender between the HIV/AIDS subgroup versus the non-HIV subgroup (p < 0.026). The incidence of HHV encephalitis was 11.3% per-year. The incidence of HHV1 (HSV) viral encephalitis, HHV5 (CMV) latent infection, and HHV4 (EBV) encephalitis accounted for 5.67, 4.2 and 0.6% per year, respectively. There were no HHV6A, B, HHV7- CNS infections observed. The incidence of HHV encephalitis was noticeably higher in HIV/AIDS patients (p = 0.002). The CSF /blood sugar ratio observed in HSV1 encephalitis was higher than in non HSV/HHV-CNS infected patients (p = 0.06). Human herpes virus, especially HSV-CNS infection was found to be common in both HIV/AIDS and non HIV patients. The incidence of VZV, EBV, HHV6 and HHV7-CNS infection were rare. Unlike the CSF/blood sugar ratio and CSF pleocytosis, clinical manifestations may not be helpful for differentiation between HSV encephalitis and non HSV/HHV-CNS infection.

Key words: Human herpes virus (HHV), central nervous system (CNS) infection, human immunodeficiency virus (HIV), viral encephalitis, herpes simplex virus (HSV), varicella zoster virus (VZV), ebstein - barr virus (EBV).