U.S. ICD-10-CM · FY 2027

A83 ICD-10-CM Code: Mosquito-borne viral encephalitis

A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.

Code definition

Official description

A83

Mosquito-borne viral encephalitis

ICD-10-CM diagnosis code · United States clinical modification

Classification

Where A83 sits

  1. 1

    Chapter 1

    Certain infectious and parasitic diseases (A00-B99)

  2. 2

    Section

    Viral and prion infections of the central nervous system (A80-A89)

  3. 3

    Category A83

    Mosquito-borne viral encephalitis

  4. 4

    Code A83

    Mosquito-borne viral encephalitis

More specific choices

Codes under A83

A83 is a non-billable category. Choose the child code that best matches the documented diagnosis.

Documentation details

Notes for this code

Inclusion terms

No inclusion terms are listed for A83.

Code first

No “code first” instruction is listed for A83.

Use additional code

No “use additional code” instruction is listed for A83.

Excludes1

Conditions that should not be reported together with this code.

No Excludes1 note is listed for A83.

Excludes2

Conditions not included here that may be reported separately when present.

  • Venezuelan equine encephalitis (A92.2)
  • West Nile fever (A92.3-)
  • West Nile virus (A92.3-)

Transparency

Source and release

Data release

U.S. ICD-10-CM · FY 2027

Effective date

Oct 1, 2026

This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.

Review the CDC/NCHS ICD-10-CM source

Code-specific guidance

Frequently asked questions

What does ICD-10-CM code A83 mean?

A83 is the FY 2027 U.S. ICD-10-CM code for “Mosquito-borne viral encephalitis.”

Is A83 a billable or specific ICD-10-CM code?

No. A83 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.

Where is A83 located in ICD-10-CM?

A83 is listed in Chapter 1, Certain infectious and parasitic diseases (A00-B99), within Viral and prion infections of the central nervous system (A80-A89) (A80–A89), under category A83, Mosquito-borne viral encephalitis.

What coding notes are listed for A83?

No inclusion terms are listed for A83 in this reference record. No code-first instruction is listed. No Excludes1 note is listed. Excludes2 notes: Venezuelan equine encephalitis (A92.2); West Nile fever (A92.3-); West Nile virus (A92.3-).

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