Chapter 1
Certain infectious and parasitic diseases
A00–B99
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FY 2027 effective October 1, 2026 · 167 categories in this chapter
Blocks in This Chapter
ICD-10-CM groups this chapter's categories into 22 blocks of three-character categories.
- A00 –A09 Intestinal infectious diseases
- A15 –A19 Tuberculosis
- A20 –A28 Certain zoonotic bacterial diseases
- A30 –A49 Other bacterial diseases
- A50 –A64 Infections with a predominantly sexual mode of transmission
- A65 –A69 Other spirochetal diseases
- A70 –A74 Other diseases caused by chlamydiae
- A75 –A79 Rickettsioses
- A80 –A89 Viral and prion infections of the central nervous system
- A90 –A99 Arthropod-borne viral fevers and viral hemorrhagic fevers
- B00 –B09 Viral infections characterized by skin and mucous membrane lesions
- B10 Other human herpesviruses
- B15 –B19 Viral hepatitis
- B20 Human immunodeficiency virus [HIV] disease
- B25 –B34 Other viral diseases
- B35 –B49 Mycoses
- B50 –B64 Protozoal diseases
- B65 –B83 Helminthiases
- B85 –B89 Pediculosis, acariasis and other infestations
- B90 –B94 Sequelae of infectious and parasitic diseases
- B95 –B97 Bacterial and viral infectious agents
- B99 Other infectious diseases
Categories
Intestinal infectious diseases (A00-A09)
- A00 Cholera Has subcategories
- A01 Typhoid and paratyphoid fevers Has subcategories
- A02 Other salmonella infections Has subcategories
- A03 Shigellosis Has subcategories
- A04 Other bacterial intestinal infections Has subcategories
- A05 Other bacterial foodborne intoxications, not elsewhere classified Has subcategories
- A06 Amebiasis Has subcategories
- A07 Other protozoal intestinal diseases Has subcategories
- A08 Viral and other specified intestinal infections Has subcategories
- A09 Infectious gastroenteritis and colitis, unspecified
Tuberculosis (A15-A19)
Certain zoonotic bacterial diseases (A20-A28)
- A20 Plague Has subcategories
- A21 Tularemia Has subcategories
- A22 Anthrax Has subcategories
- A23 Brucellosis Has subcategories
- A24 Glanders and melioidosis Has subcategories
- A25 Rat-bite fevers Has subcategories
- A26 Erysipeloid Has subcategories
- A27 Leptospirosis Has subcategories
- A28 Other zoonotic bacterial diseases, not elsewhere classified Has subcategories
Other bacterial diseases (A30-A49)
- A30 Leprosy [Hansen's disease] Has subcategories
- A31 Infection due to other mycobacteria Has subcategories
- A32 Listeriosis Has subcategories
- A33 Tetanus neonatorum
- A34 Obstetrical tetanus
- A35 Other tetanus
- A36 Diphtheria Has subcategories
- A37 Whooping cough Has subcategories
- A38 Scarlet fever Has subcategories
- A39 Meningococcal infection Has subcategories
- A40 Streptococcal sepsis Has subcategories
- A41 Other sepsis Has subcategories
- A42 Actinomycosis Has subcategories
- A43 Nocardiosis Has subcategories
- A44 Bartonellosis Has subcategories
- A46 Erysipelas
- A48 Other bacterial diseases, not elsewhere classified Has subcategories
- A49 Bacterial infection of unspecified site Has subcategories
Infections with a predominantly sexual mode of transmission (A50-A64)
- A50 Congenital syphilis Has subcategories
- A51 Early syphilis Has subcategories
- A52 Late syphilis Has subcategories
- A53 Other and unspecified syphilis Has subcategories
- A54 Gonococcal infection Has subcategories
- A55 Chlamydial lymphogranuloma (venereum)
- A56 Other sexually transmitted chlamydial diseases Has subcategories
- A57 Chancroid
- A58 Granuloma inguinale
- A59 Trichomoniasis Has subcategories
- A60 Anogenital herpesviral [herpes simplex] infections Has subcategories
- A63 Other predominantly sexually transmitted diseases, not elsewhere classified Has subcategories
- A64 Unspecified sexually transmitted disease
Other spirochetal diseases (A65-A69)
Other diseases caused by chlamydiae (A70-A74)
Rickettsioses (A75-A79)
Viral and prion infections of the central nervous system (A80-A89)
- A80 Acute poliomyelitis Has subcategories
- A81 Atypical virus infections of central nervous system Has subcategories
- A82 Rabies Has subcategories
- A83 Mosquito-borne viral encephalitis Has subcategories
- A84 Tick-borne viral encephalitis Has subcategories
- A85 Other viral encephalitis, not elsewhere classified Has subcategories
- A86 Unspecified viral encephalitis
- A87 Viral meningitis Has subcategories
- A88 Other viral infections of central nervous system, not elsewhere classified Has subcategories
- A89 Unspecified viral infection of central nervous system
Arthropod-borne viral fevers and viral hemorrhagic fevers (A90-A99)
- A90 Dengue fever [classical dengue]
- A91 Dengue hemorrhagic fever
- A92 Other mosquito-borne viral fevers Has subcategories
- A93 Other arthropod-borne viral fevers, not elsewhere classified Has subcategories
- A94 Unspecified arthropod-borne viral fever
- A95 Yellow fever Has subcategories
- A96 Arenaviral hemorrhagic fever Has subcategories
- A98 Other viral hemorrhagic fevers, not elsewhere classified Has subcategories
- A99 Unspecified viral hemorrhagic fever
Viral infections characterized by skin and mucous membrane lesions (B00-B09)
- B00 Herpesviral [herpes simplex] infections Has subcategories
- B01 Varicella [chickenpox] Has subcategories
- B02 Zoster [herpes zoster] Has subcategories
- B03 Smallpox
- B04 Monkeypox
- B05 Measles Has subcategories
- B06 Rubella [German measles] Has subcategories
- B07 Viral warts Has subcategories
- B08 Other viral infections characterized by skin and mucous membrane lesions, not elsewhere classified Has subcategories
- B09 Unspecified viral infection characterized by skin and mucous membrane lesions