All ICD10 Codes
Chapter 1

A00–B99: Certain Infectious and Parasitic Diseases

Certain Infectious and Parasitic Diseases diagnostic classification updated for 2026.

Chapter 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.-)
All CodesBillable Only
Internal Codes
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  • A80.30—

    Acute paralytic poliomyelitis, unspecified

  • A80.39—

    Other acute paralytic poliomyelitis

  • A80.4—

    Acute nonparalytic poliomyelitis

  • A80.9—

    Acute poliomyelitis, unspecified

  • A81—

    Atypical virus infections of central nervous system

  • A81.0—

    Creutzfeldt-Jakob disease

  • A81.00—

    Creutzfeldt-Jakob disease, unspecified

  • A81.01—

    Variant Creutzfeldt-Jakob disease

  • A81.09—

    Other Creutzfeldt-Jakob disease

  • A81.1—

    Subacute sclerosing panencephalitis

  • A81.2—

    Progressive multifocal leukoencephalopathy

  • A81.8—

    Other atypical virus infections of central nervous system

  • A81.81—

    Kuru

  • A81.82—

    Gerstmann-Sträussler-Scheinker syndrome

  • A81.83—

    Fatal familial insomnia

  • A81.89—

    Other atypical virus infections of central nervous system

  • A81.9—

    Atypical virus infection of central nervous system, unspecified

  • A82—

    Rabies

  • A82.0—

    Sylvatic rabies

  • A82.1—

    Urban rabies

  • A82.9—

    Rabies, unspecified

  • A83—

    Mosquito-borne viral encephalitis

  • A83.0—

    Japanese encephalitis

  • A83.1—

    Western equine encephalitis

  • A83.2—

    Eastern equine encephalitis

  • A83.3—

    St Louis encephalitis

  • A83.4—

    Australian encephalitis

  • A83.5—

    California encephalitis

  • A83.6—

    Rocio virus disease

  • A83.8—

    Other mosquito-borne viral encephalitis

  • A83.9—

    Mosquito-borne viral encephalitis, unspecified

  • A84—

    Tick-borne viral encephalitis

  • A84.0—

    Far Eastern tick-borne encephalitis [Russian spring-summer encephalitis]

  • A84.1—

    Central European tick-borne encephalitis

  • A84.8—

    Other tick-borne viral encephalitis

  • A84.81—

    Powassan virus disease

  • A84.89—

    Other tick-borne viral encephalitis

  • A84.9—

    Tick-borne viral encephalitis, unspecified

  • A85—

    Other viral encephalitis, not elsewhere classified

  • A85.0—

    Enteroviral encephalitis

  • A85.1—

    Adenoviral encephalitis

  • A85.2—

    Arthropod-borne viral encephalitis, unspecified

  • A85.8—

    Other specified viral encephalitis

  • A86—

    Unspecified viral encephalitis

  • A87—

    Viral meningitis

  • A87.0—

    Enteroviral meningitis

  • A87.1—

    Adenoviral meningitis

  • A87.2—

    Lymphocytic choriomeningitis

  • A87.8—

    Other viral meningitis

  • A87.9—

    Viral meningitis, unspecified

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