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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  • A69.2—

    Lyme disease

  • A69.20—

    Lyme disease, unspecified

  • A69.21—

    Meningitis due to Lyme disease

  • A69.22—

    Other neurologic disorders in Lyme disease

  • A69.23—

    Arthritis due to Lyme disease

  • A69.29—

    Other conditions associated with Lyme disease

  • A69.8—

    Other specified spirochetal infections

  • A69.9—

    Spirochetal infection, unspecified

  • A70—

    Chlamydia psittaci infections

  • A71—

    Trachoma

  • A71.0—

    Initial stage of trachoma

  • A71.1—

    Active stage of trachoma

  • A71.9—

    Trachoma, unspecified

  • A74—

    Other diseases caused by chlamydiae

  • A74.0—

    Chlamydial conjunctivitis

  • A74.8—

    Other chlamydial diseases

  • A74.81—

    Chlamydial peritonitis

  • A74.89—

    Other chlamydial diseases

  • A74.9—

    Chlamydial infection, unspecified

  • A75—

    Typhus fever

  • A75.0—

    Epidemic louse-borne typhus fever due to Rickettsia prowazekii

  • A75.1—

    Recrudescent typhus [Brill's disease]

  • A75.2—

    Typhus fever due to Rickettsia typhi

  • A75.3—

    Typhus fever due to Rickettsia tsutsugamushi

  • A75.9—

    Typhus fever, unspecified

  • A77—

    Spotted fever [tick-borne rickettsioses]

  • A77.0—

    Spotted fever due to Rickettsia rickettsii

  • A77.1—

    Spotted fever due to Rickettsia conorii

  • A77.2—

    Spotted fever due to Rickettsia siberica

  • A77.3—

    Spotted fever due to Rickettsia australis

  • A77.4—

    Ehrlichiosis

  • A77.40—

    Ehrlichiosis, unspecified

  • A77.41—

    Ehrlichiosis chaffeensis [E. chaffeensis]

  • A77.49—

    Other ehrlichiosis

  • A77.8—

    Other spotted fevers

  • A77.9—

    Spotted fever, unspecified

  • A78—

    Q fever

  • A79—

    Other rickettsioses

  • A79.0—

    Trench fever

  • A79.1—

    Rickettsialpox due to Rickettsia akari

  • A79.8—

    Other specified rickettsioses

  • A79.81—

    Rickettsiosis due to Ehrlichia sennetsu

  • A79.82—

    Anaplasmosis [A. phagocytophilum]

  • A79.89—

    Other specified rickettsioses

  • A79.9—

    Rickettsiosis, unspecified

  • A80—

    Acute poliomyelitis

  • A80.0—

    Acute paralytic poliomyelitis, vaccine-associated

  • A80.1—

    Acute paralytic poliomyelitis, wild virus, imported

  • A80.2—

    Acute paralytic poliomyelitis, wild virus, indigenous

  • A80.3—

    Acute paralytic poliomyelitis, other and unspecified

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