Viral meningitis

Arun Venkatesan MD PhD (

Dr. Venkatesan of Johns Hopkins School of Medicine has no relevant financial relationships to disclose.

Luisa Diaz-Arias MD (

Dr. Diaz-Arias of Johns Hopkins School of Medicine has no relevant financial relationships to disclose.

Christina M Marra MD, editor. (

Dr. Marra of the University of Washington School of Medicine owned stock in Johnson & Johnson and McKesson within the past 12 months.

Originally released February 22, 1995; last updated September 16, 2019; expires September 16, 2022


Meningitis refers to inflammation of the meninges and can occur in the setting of infection or, less commonly, autoimmunity (Mount and Boyle 2017; Wright et al 2019). About 8 to 10 cases per 100,000 persons of viral meningitis are estimated to occur in the United States each year, with an annual cost of $200 to $300 million (Centers for Disease Control and Prevention 2003; Khetsuriani et al 2006). Enteroviruses cause most cases of viral meningitis, followed by herpes virus, and in some parts of the world, arthropod-borne viruses.

Key points


• The most common symptoms of viral meningitis are headache, fever, and neck stiffness.


• Nonpolio enteroviruses account for the majority of viral meningitis cases in the United States (up to 61% of cases), followed by herpes simplex and varicella zoster virus (McGill et al 2017; Griffiths et al 2018).


• Viral meningitis and bacterial meningitis cannot be reliably differentiated based on symptoms and signs; therefore, CSF analysis is needed.


• CSF will classically show a lymphocytic pleocytosis (usually less than 300 cells/mm3), a normal glucose concentration, normal or mildly elevated protein concentration, a negative Gram stain, and negative bacterial culture.

Historical note and terminology

In 1925 Wallgren recognized viruses as a cause of aseptic meningitis (Wallgren 1925). In the early part of the 20th century, it was known that meningeal inflammation occurred as part of paralytic poliomyelitis and epidemic parotitis. In the 1930s, filterable agents (viruses) were recovered from the CSF of patients with aseptic meningitis (lymphocytic choriomeningitis virus) (Rivers and Scott 1935).

Subsequently, it was recognized that aseptic meningitis was a syndrome that could have multiple causes, both infectious and noninfectious (Wallgren 1951; Adair et al 1953; Wright et al 2019). The syndrome consists of symptoms and signs of meningeal irritation, a CSF pleocytosis, and negative stains and cultures for bacteria, fungi, and parasites.

The content you are trying to view is available only to logged in, current MedLink Neurology subscribers.

If you are a subscriber, please log in.

If you are a former subscriber or have registered before, please log in first and then click select a Service Plan or contact Subscriber Services. Site license users, click the Site License Acces link on the Homepage at an authorized computer.

If you have never registered before, click Learn More about MedLink Neurology  or view available Service Plans.