Journal of Preventive Medicine & Infectious Diseases

Abstract

Background: Human herpesvirus 6 (HHV-6), particularly HHV-6B, is an underrecognized cause of pediatric encephalitis and acute encephalopathy. In tropical settings, diagnostic evaluation is often focused on endemic viral etiologies, which may delay consideration of HHV-6 in cases of unexplained neurological deterioration.

Methods: Postmortem blood and cerebrospinal fluid (CSF) samples from a male child in Sri Lanka were received by the National Virology Reference Laboratory for virological investigation with the history of sudden onset fever and as with encephalitis. Initial testing targeted common endemic and neurotropic viral pathogens, including dengue virus, Japanese encephalitis virus, SARS-CoV-2, influenza viruses, enteroviruses, and herpes simplex virus (HSV). Subsequent molecular testing for HHV-6 was performed using a commercial real-time typing PCR assay capable of differentiating HHV-6A and HHV-6B.

Results: All initial investigations for common viral etiologies were negative. Postmortem findings demonstrated massive cerebral edema. HHV-6B DNA was detected by real-time typing PCR.

Conclusion: The detection of HHV-6B DNA in association with severe cerebral edema supports a probable role of HHV-6B in the fatal encephalopathic illness. This scenario highlights the importance of incorporating molecular testing for HHV-6 in the diagnostic evaluation of unexplained pediatric encephalitis and rapid neurological deterioration, particularly in tropical regions where attention is often directed toward endemic viral causes.