A83

Non-Billable

ChapterA00–B99

Rankcategory

Official Description

Mosquito-borne viral encephalitis

Use a more specific code (9 billable)

A83.0Japanese encephalitis A83.1Western equine encephalitis A83.2Eastern equine encephalitis A83.3St Louis encephalitis A83.4Australian encephalitis A83.5California encephalitis A83.6Rocio virus disease A83.8Other mosquito-borne viral encephalitis A83.9Mosquito-borne viral encephalitis, unspecified

Metadata & Insights

•Non-billable category (requires more specific sub-code).
•Chapter 1: Certain Infectious and Parasitic Diseases (A00-B99).

CH1 Parent Instructions

Includes

diseases generally recognized as communicable or transmissible

Excludes1(Not coded here. Use a different code.)

certain localized infections - see body system-related chapters

Excludes2(Not included here. Code separately if applicable.)

carrier or suspected carrier of infectious disease (Z22.-)
infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
infectious and parasitic diseases specific to the perinatal period (P35-P39)
influenza and other acute respiratory infections (J00-J22)

Use Additional Code

code to identify resistance to antimicrobial drugs (Z16.-)

A80-A89 Parent Instructions

Excludes1(Not coded here. Use a different code.)

postpolio syndrome (G14)
sequelae of poliomyelitis (B91)
sequelae of viral encephalitis (B94.1)

Instructional Notes

Includes

mosquito-borne viral meningoencephalitis

Excludes2(Not included here. Code separately if applicable.)

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

Clinical Hierarchy

BillableHas subcodes

CH1Certain infectious and parasitic diseases (A00-B99)

A80-A89Viral and prion infections of the central nervous system (A80-A89)

A83Mosquito-borne viral encephalitisNot billable

A83.0Japanese encephalitisBillable

A83.1Western equine encephalitisBillable

A83.2Eastern equine encephalitisBillable

A83.3St Louis encephalitisBillable

A83.4Australian encephalitisBillable

A83.5California encephalitisBillable

A83.6Rocio virus diseaseBillable

A83.8Other mosquito-borne viral encephalitisBillable

A83.9Mosquito-borne viral encephalitis, unspecifiedBillable

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to A83:

blockA80-A89

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

View context instructions

chapterCH1

Certain infectious and parasitic diseases (A00-B99)

View context instructions

MS-DRG Classification

2026

No direct MS-DRG triggers identified.

Cross Reference

Find Procedures (ICD-10-PCS)

Find surgical and procedural codes related to Mosquito-borne viral encephalitis.

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