Detection of varicella-zoster virus from cerebrospinal fluid using advanced fragment analysis in a child with encephalitis: a case report

BACKGROUND: Varicella zoster virus (VZV) encephalitis is an infectious inflammatory disease of brain that can cause irreversible mental damage without timely treatment. In fact, many viruses can cause encephalitis, and the viral loads in cerebrospinal fluid (CSF) in the early stage of the disease are usually too low to be detected. Here we report a case of VZV encephalitis diagnosed by advanced fragment analysis (AFA), which could potentially to contribute to early diagnosis of VZV central nervous system (CNS) infections with a small volume of CSF samples. CASE PRESENTATION: A 10-year-old boy was admitted to the hospital with obvious neurological symptoms of headache, dizziness and vomiting for one day. Physical examination showed left facial paralysis. Complete blood count (CBC) test only showed an unspecific inflammation, and the culture of cerebrospinal fluid and microscopic staining examination were all negative. AFA was performed to screen the common 18 encephalitis related pathogens in CSF. Obvious VZV DNA fragments were observed by capillary electrophoresis at 160 nt, suggesting the existence of VZV CNS infection in children. The results were consistence with real-time quantitative PCR and concomitant symptoms in the acute stage of the disease. CONCLUSIONS: We report a case of acute VZV encephalitis in a child without obvious skin manifestations, which was rapidly diagnosed by AFA. Overall, we would recommend the use of AFA analysis as the rapid screening system for the identification and differentiation of encephalitis pathogens in children.