Etiology of aseptic meningitis and encephalitis in an adult population

Related Experiment Video

Updated: Aug 13, 2026

Inducing Meningococcal Meningitis Serogroup C in Mice via Intracisternal Delivery
10:03

Inducing Meningococcal Meningitis Serogroup C in Mice via Intracisternal Delivery

Published on: November 5, 2019

L Kupila1, T Vuorinen, R Vainionpää

  • 1Department of Neurology, Turku University Hospital, Turku, Finland. laura.kupila@tyks.fi

Neurology
|January 13, 2006
PubMed
Abstract

Insights

Enteroviruses and herpes simplex virus type 2 (HSV-2) are the primary causes of adult aseptic meningitis. Polymerase chain reaction (PCR) aids diagnosis, but the etiology of most adult encephalitis cases remains unknown.

Area of Science:

  • Neurology
  • Infectious Diseases
  • Microbiology

Background:

  • Aseptic meningitis and encephalitis are serious neurological conditions with diverse etiologies.
  • Accurate and timely diagnosis is crucial for effective patient management.
  • Modern diagnostic techniques are essential for identifying causative agents.

Purpose of the Study:

  • To investigate the causes of aseptic meningitis and encephalitis in adults.
  • To evaluate the utility of contemporary microbiologic methods, including PCR, in diagnosing these conditions.
  • To determine the proportion of cases with identified etiologies.

Main Methods:

  • A cohort of adult patients (>=16 years) with aseptic meningitis or encephalitis was studied.
  • Cerebrospinal fluid (CSF) and serum samples were analyzed using PCR and antibody testing for common neurotropic viruses like enteroviruses, herpes simplex virus (HSV) 1 and 2, and varicella zoster virus (VZV).
  • Virus cultures were performed on various specimen types.

Main Results:

  • The etiology was identified in 66% of aseptic meningitis cases, with enteroviruses (26%), HSV-2 (17%), and VZV (8%) being most common.
  • In encephalitis cases, etiology was identified in 36%, with VZV (12%), HSV-1 (9%), and tick-borne encephalitis virus (9%) as leading pathogens.
  • PCR successfully diagnosed 43% of meningitis cases and 17% of encephalitis cases.

Conclusions:

  • Enteroviruses and HSV-2 are the predominant causes of adult aseptic meningitis.
  • PCR demonstrates significant diagnostic value for aseptic meningitis.
  • The etiology of a substantial proportion of adult encephalitis cases remains undetermined.

More Related Videos

Non-Invasive Model of Neuropathogenic Escherichia coli Infection in the Neonatal Rat08:27

Non-Invasive Model of Neuropathogenic Escherichia coli Infection in the Neonatal Rat

Published on: October 29, 2014

Neisseria meningitidis Infection of Induced Pluripotent Stem-Cell Derived Brain Endothelial Cells10:12

Neisseria meningitidis Infection of Induced Pluripotent Stem-Cell Derived Brain Endothelial Cells

Published on: July 14, 2020

Related Concept Videos

Encephalitis l: Introduction01:19

Encephalitis l: Introduction

Encephalitis is inflammation of the brain parenchyma, most often due to infections or autoimmune processes. It presents with neuropsychiatric features such as fever, altered mental status, behavioral changes, cognitive dysfunction, seizures, focal deficits, and sometimes autonomic instability. In some cases, the meninges are also involved, resulting in meningoencephalitis.Infectious CausesInfectious encephalitis is most commonly viral but can also result from bacterial, fungal, or parasitic...
Bacterial Meningitis I: Introduction01:22

Bacterial Meningitis I: Introduction

Bacterial meningitis is a severe, life-threatening inflammation of the meninges, particularly the pia mater and arachnoid mater, affecting the subarachnoid space, ventricles, and cerebrospinal fluid (CSF). If untreated, it can lead to significant neurological complications or death.Causative AgentsCommon pathogens vary with age and immune status. In adults, major organisms include Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. Streptococcus agalactiae (group B...
Encephalitis ll: Pathophysiology01:26

Encephalitis ll: Pathophysiology

Encephalitis is inflammation of the brain parenchyma caused by direct viral invasion or immune-mediated mechanisms triggered by infections or tumors. Both processes lead to neuronal injury, disrupted neurotransmission, and diverse neurological symptoms, often with overlapping clinical and pathological features.Autoimmune EncephalitisIn autoimmune encephalitis, antibodies target neuronal antigens on cell surfaces, synapses, or within neurons. A key example is anti-NMDAR encephalitis, which can...
Bacterial Meningitis II: Pathophysiology01:26

Bacterial Meningitis II: Pathophysiology

Bacterial meningitis typically begins when pathogens such as Neisseria meningitidis and Streptococcus pneumoniae colonize the nasopharynx and invade the bloodstream. This process is facilitated by bacterial virulence factors, such as polysaccharide capsules, which resist phagocytosis and complement-mediated killing. Less commonly, bacteria reach the central nervous system via contiguous spread from infections like otitis media or sinusitis, through congenital or acquired dural defects, or...
Viral Meningitis01:18

Viral Meningitis

Viral meningitis is the most common form of meningitis and is often referred to as aseptic meningitis to indicate the absence of bacterial involvement. It is generally milder than bacterial meningitis, with symptoms including fever, headache, stiff neck, drowsiness, nausea, photophobia, and vomiting. Rarely, more severe manifestations or death may occur. Common causative agents include enteroviruses, particularly coxsackie A and B viruses and echoviruses, all members of the Enterovirus genus...
Bacterial Meningitis01:24

Bacterial Meningitis

Bacterial meningitis is a severe infectious disease involving inflammation of the meninges, the protective membranes surrounding the brain and spinal cord. It occurs when pathogenic bacteria cross the blood–brain barrier and enter the cerebrospinal fluid. Common causative organisms include Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae type b, Listeria monocytogenes, and Escherichia coli K1. The exact route of entry varies by pathogen and host condition.Routes of Entry...