What are the most likely viral pathogen types causing meningitis or encephalitis, listed from most common to least common?

From the Guidelines

The most common viral pathogens causing meningitis or encephalitis, from most common to least common, are enteroviruses, herpes simplex virus, arboviruses, varicella-zoster virus, mumps virus, HIV, lymphocytic choriomeningitis virus, and adenoviruses.

Key Points

• Enteroviruses are the leading cause of viral meningitis, accounting for a significant proportion of cases where a causative agent is identified, with peak incidence during summer and fall months 1.
• Herpes simplex viruses are the most common cause of sporadic viral encephalitis, with HSV-1 typically affecting adults and HSV-2 more commonly affecting neonates 1.
• Arboviruses tend to cause disease in specific geographic regions and seasons when their arthropod vectors are active 1.
• The clinical presentation varies by pathogen, with enteroviruses typically causing a self-limited illness while HSV encephalitis requires prompt treatment with acyclovir to prevent significant morbidity and mortality 1.

Diagnosis and Treatment

• Diagnosis typically involves cerebrospinal fluid analysis with PCR testing for specific viral pathogens, which has largely replaced viral culture as the diagnostic standard 1.
• Prompt treatment with acyclovir is essential for HSV encephalitis, with a recommended dose of 10 mg/kg IV every 8 hours for 14-21 days 1.

Epidemiology

• The incidence of viral meningitis and encephalitis varies by region and season, with enteroviruses being the most common cause of viral meningitis in many areas 1.
• Herpes simplex viruses are a common cause of sporadic viral encephalitis, with a significant impact on morbidity and mortality 1.

From the Research

Viral Pathogen Types Causing Meningitis or Encephalitis

The most likely viral pathogen types causing meningitis or encephalitis, listed from most common to least common, are:

• West Nile virus (WNV) 2, 3, 4, 5, 6
• La Crosse virus (LACV) 2, 3, 5, 6
• Jamestown Canyon virus (JCV) 2, 3, 5, 6
• Powassan virus (POWV) 2, 3, 5, 6
• Eastern equine encephalitis virus (EEEV) 2, 3, 5, 6
• St. Louis encephalitis virus (SLEV) 3, 5, 6
• California serogroup viruses 5

Prevalence of Viral Pathogen Types

The prevalence of these viral pathogen types varies by year and region, but WNV is consistently the leading cause of domestically acquired arboviral disease in the United States 2, 3, 4, 5, 6. The incidence of WNV neuroinvasive disease has been reported to be as high as 0.61 per 100,000 population 3.

Surveillance and Prevention

Maintaining surveillance and prevention efforts is crucial to reduce the transmission and prevalence of these viral pathogen types 2, 3, 4, 5, 6. Healthcare providers should consider arboviral infections in the differential diagnosis of aseptic meningitis and encephalitis, and promptly report cases to public health authorities 3. Prevention depends on community and household efforts to reduce vector populations and personal protective measures to prevent mosquito and tick bites 3, 4.