Study: Varicella Zoster Virus Could Be a Major Cause of Aseptic Meningitis, Encephalitis, and Myelitis

New study findings suggest that the varicella zoster virus (VZV) is a significant cause of central nervous system (CNS) infectious syndrome, although further research should evaluate the relative importance of VZV in CNS infectious syndromes, regardless of any association with a typical herpetic rash.¹

Image credit: Sunday Cat Studio | stock.adobe.com

CNS infections involve the brain, spinal cord, optic nerves, and their covering membranes. The infections are linked with substantial morbidity, mortality, and major implications that could impact the quality of life for individuals affected.² Along with VZV, other viruses like meningitis, encephalitis, and myelitis are major causes of CNS infectious syndromes.¹

VZV is the virus that causes chickenpox and shingles. According to the CDC, shingles typically presents as a painful rash and is estimated to impact 1 million individuals each year in the US. In most cases, individuals only develop shingles once in their lifetime although the illness can reoccur.³

In an observational study conducted at Kaplan Medical Center in Israel, researchers assessed the proportion of VZV identification amongst other common viral causes in adult patients who presented primarily with CNS infection syndromes, meningitis, encephalitis, and myelitis, with aseptic cerebrospinal fluid (CSF) profile subjected to molecular tests for common viral causes. Additionally, the researchers evaluated the presence of herpetic rash at the time of neurologic VZV-related illness.¹

In the observational study, a total of 1519 molecular test results were performed and collected for VZV between July 1, 2014, and March 31, 2019. The study included a total of 176 individuals aged 16 years and older with CNS infection with an aseptic CSF profile who were subjected to molecular tests for herpes viruses, HSV-1, HSV-2, VZV, enteroviruses, and IgM for West Nile virus (WNV), according to study authors.¹

Using electronic records, the researchers obtained patient information including age, gender, chronic diseases, clinical signs, neuroimaging tests, days of hospitalization, and outcome. PCR testing was performed to identify the presence of HSV-1 and HSV-2 or VZV.¹

Additionally, physicians could decide to test the patient's spinal fluid if their symptoms and signs indicated a brain or spinal cord infection. The spinal fluid was tested for common viruses to determine the cause of the infection.¹

Of the 178 cases with aseptic CSF, the most common causes of meningitis were unknown (55.9%), enterovirus (18.9%), VZV (14.4%), and HSV-1 (6.3%). For encephalitis, the most common causes were unknown (47.6%), HSV (17.5%), VZV (12.7%), and WNV (15.9%). VZV was the most common cause of myelitis, accounting for 66.7% of cases. Notably, a typical herpetic rash was only present in 39.28% of VZV CNS infection cases.¹

The findings suggest that VZV is a common cause of CNS infections, even when there is no visible rash. It can cause meningitis, encephalitis, and myelitis. However, the exact role of acyclovir treatment for these infections is still unclear. The study authors noted that there is a need for wider use of molecular testing to diagnose VZV and other viral infections, as many cases remain undiagnosed.¹

REFERENCES

1. The Role of Varicella Zoster Virus (VZV) in Central Nervous System Infectious Syndromes. Wiley. News release, November 13, 2024. Accessed December 18, 2024. https://onlinelibrary.wiley.com/doi/10.1155/cjid/6664417.

2. Central Nervous System Infections. National Library of Medicine. News release. May 7, 2013. Accessed December 18, 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC7122753/#:~:text=Central%20nervous%20system%20(CNS)%20infections,sources%20or%20foci%20of%20infection.

3. About Shingles (Herpes Zoster). CDC. News release. May 10, 2024. Accessed December 18, 2024. https://www.cdc.gov/shingles/about/index.html.