A83
Non-Billable

Mosquito-borne viral encephalitis

Non-Billable / Non-Specific Code

What is Mosquito-borne viral encephalitis?

ICD-10-CM A83 is the diagnosis code for Mosquito-borne viral encephalitis. This code falls under the section "Viral and prion infections of the central nervous system" within Chapter 1 — Certain infectious and parasitic diseases (A00-B99). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.

â„šī¸ Excludes2

Coding Guidelines for A83

â„šī¸ Type 2 Excludes (Code separately if applicable)

The following conditions are not included in A83. If the patient has both, code each condition separately:

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

ICD-10-CM Code Hierarchy

Understanding where A83 sits in the ICD-10-CM classification helps ensure proper coding:

Sub-Codes 9 entries
A83.0Japanese encephalitisBillableA83.1Western equine encephalitisBillableA83.2Eastern equine encephalitisBillableA83.3St Louis encephalitisBillableA83.4Australian encephalitisBillableA83.5California encephalitisBillableA83.6Rocio virus diseaseBillableA83.8Other mosquito-borne viral encephalitisBillableA83.9Mosquito-borne viral encephalitis, unspecifiedBillable
Related Codes

Frequently Asked Questions

Is A83 a billable ICD-10-CM code?

No, A83 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.

What does A83 mean?

A83 is the ICD-10-CM diagnosis code for "Mosquito-borne viral encephalitis". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.

What section is A83 in?

A83 is located in Section A80-A89 — "Viral and prion infections of the central nervous system" within Chapter 1 of the ICD-10-CM Tabular List.

What are the sub-codes of A83?

A83 has 9 sub-code(s) that provide more specific detail: A83.0, A83.1, A83.2, A83.3, A83.4 and more.

When should I use A83?

Use A83 when the patients documented diagnosis matches "Mosquito-borne viral encephalitis" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.

People Also Ask

What is the ICD-10 code for Mosquito-borne viral encephalitis?

The ICD-10-CM code for Mosquito-borne viral encephalitis is A83.

Can A83 be used for primary diagnosis?

No, A83 is non-billable. Use a more specific sub-code for primary diagnosis billing.

What chapter is A83 in?

A83 is in Chapter 1 of the ICD-10-CM Tabular List.

Is A83 valid for 2026?

Yes, A83 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.

See Also

← PreviousA82.9Rabies, unspecifiedNext →A83.0Japanese encephalitis
Code Details
A83
Mosquito-borne viral encephalitis
Non-Billable / Non-Specific Code
1 — Certain infectious and parasitic diseases (A00-B99)
A80-A89 — Viral and prion infections of the central nervous system
2026 ICD-10-CM