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.-)
Internal Codes
  • B95|

    Streptococcus, Staphylococcus, and Enterococcus as the cause of diseases classified elsewhere

  • B95.0|

    Streptococcus, group A, as the cause of diseases classified elsewhere

  • B95.1|

    Streptococcus, group B, as the cause of diseases classified elsewhere

  • B95.2|

    Enterococcus as the cause of diseases classified elsewhere

  • B95.3|

    Streptococcus pneumoniae as the cause of diseases classified elsewhere

  • B95.4|

    Other streptococcus as the cause of diseases classified elsewhere

  • B95.5|

    Unspecified streptococcus as the cause of diseases classified elsewhere

  • B95.6|

    Staphylococcus aureus as the cause of diseases classified elsewhere

  • B95.61|

    Methicillin susceptible Staphylococcus aureus infection as the cause of diseases classified elsewhere

  • B95.62|

    Methicillin resistant Staphylococcus aureus infection as the cause of diseases classified elsewhere

  • B95.7|

    Other staphylococcus as the cause of diseases classified elsewhere

  • B95.8|

    Unspecified staphylococcus as the cause of diseases classified elsewhere

  • B96|

    Other bacterial agents as the cause of diseases classified elsewhere

  • B96.0|

    Mycoplasma pneumoniae [M. pneumoniae] as the cause of diseases classified elsewhere

  • B96.1|

    Klebsiella pneumoniae [K. pneumoniae] as the cause of diseases classified elsewhere

  • B96.2|

    Escherichia coli [E. coli ] as the cause of diseases classified elsewhere

  • B96.20|

    Unspecified Escherichia coli [E. coli] as the cause of diseases classified elsewhere

  • B96.21|

    Shiga toxin-producing Escherichia coli [E. coli] [STEC] O157 as the cause of diseases classified elsewhere

  • B96.22|

    Other specified Shiga toxin-producing Escherichia coli [E. coli] [STEC] as the cause of diseases classified elsewhere

  • B96.23|

    Unspecified Shiga toxin-producing Escherichia coli [E. coli] [STEC] as the cause of diseases classified elsewhere

  • B96.29|

    Other Escherichia coli [E. coli] as the cause of diseases classified elsewhere

  • B96.3|

    Hemophilus influenzae [H. influenzae] as the cause of diseases classified elsewhere

  • B96.4|

    Proteus (mirabilis) (morganii) as the cause of diseases classified elsewhere

  • B96.5|

    Pseudomonas (aeruginosa) (mallei) (pseudomallei) as the cause of diseases classified elsewhere

  • B96.6|

    Bacteroides fragilis [B. fragilis] as the cause of diseases classified elsewhere

  • B96.7|

    Clostridium perfringens [C. perfringens] as the cause of diseases classified elsewhere

  • B96.8|

    Other specified bacterial agents as the cause of diseases classified elsewhere

  • B96.81|

    Helicobacter pylori [H. pylori] as the cause of diseases classified elsewhere

  • B96.82|

    Vibrio vulnificus as the cause of diseases classified elsewhere

  • B96.83|

    Acinetobacter baumannii as the cause of diseases classified elsewhere

  • B96.89|

    Other specified bacterial agents as the cause of diseases classified elsewhere

  • B97|

    Viral agents as the cause of diseases classified elsewhere

  • B97.0|

    Adenovirus as the cause of diseases classified elsewhere

  • B97.1|

    Enterovirus as the cause of diseases classified elsewhere

  • B97.10|

    Unspecified enterovirus as the cause of diseases classified elsewhere

  • B97.11|

    Coxsackievirus as the cause of diseases classified elsewhere

  • B97.12|

    Echovirus as the cause of diseases classified elsewhere

  • B97.19|

    Other enterovirus as the cause of diseases classified elsewhere

  • B97.2|

    Coronavirus as the cause of diseases classified elsewhere

  • B97.21|

    SARS-associated coronavirus as the cause of diseases classified elsewhere

  • B97.29|

    Other coronavirus as the cause of diseases classified elsewhere

  • B97.3|

    Retrovirus as the cause of diseases classified elsewhere

  • B97.30|

    Unspecified retrovirus as the cause of diseases classified elsewhere

  • B97.31|

    Lentivirus as the cause of diseases classified elsewhere

  • B97.32|

    Oncovirus as the cause of diseases classified elsewhere

  • B97.33|

    Human T-cell lymphotrophic virus, type I [HTLV-I] as the cause of diseases classified elsewhere

  • B97.34|

    Human T-cell lymphotrophic virus, type II [HTLV-II] as the cause of diseases classified elsewhere

  • B97.35|

    Human immunodeficiency virus, type 2 [HIV 2] as the cause of diseases classified elsewhere

  • B97.39|

    Other retrovirus as the cause of diseases classified elsewhere

  • B97.4|

    Respiratory syncytial virus as the cause of diseases classified elsewhere

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