A85.2

What This Code Means

This code describes inflammation of the brain caused by a virus transmitted through insect bites (such as mosquitoes or ticks), when the specific type of virus has not been identified. It represents a serious infection affecting brain tissue that requires medical attention.

Coding Tips

• •Use this code only when the specific arthropod-borne virus (such as West Nile virus, dengue, or Zika) cannot be determined; if the specific virus is identified, use a more specific A85 subcategory code instead
• •Ensure documentation supports encephalitis (brain inflammation) rather than meningitis or other viral infections; review provider notes for clinical findings such as fever, headache, altered mental status, or neurological symptoms