Coding direction: Influenza due to influenza A/H5N1 (avian influenza)

Effective April 1, 2025 — This bulletin clarifies the use of J09 Influenza due to identified zoonotic or pandemic influenza virus and updates coding direction for classifying influenza A/H5N1 virus using the Canadian Emergency Department Diagnosis Shortlist (CED-DxS). 

Clarification: Coding direction for DAD and NACRS

As communicated in 2024, influenza A/H5N1 virus is classified to J09 Influenza due to identified zoonotic or pandemic influenza virus.

Updated direction: A/H5N1 [avian influenza] is the only type of influenza virus that is classified to J09. All other identified influenza virus strains are classified to J10.– Influenza due to other identified influenza virus.

Zoonotic influenza viruses are influenza type A viruses that are transmitted from animals to humans; they are rarely transmitted from one human to another. Zoonotic influenza is also known as non-seasonal influenza, as it may be transmitted at any time of the year when people are exposed to animal influenza viruses.

Seasonal influenza viruses are those that have adapted to humans; they are strains of influenza virus types A and B that cause respiratory illnesses in humans annually. Seasonal influenza spreads between humans and can cause mild to severe illnesses. Seasonal influenza virus strains are classified to J10.– Influenza due to identified seasonal influenza virus.

Update: Capturing influenza A/H5N1 virus using CED-DxS (effective April 1, 2025)

The ICD-10-CA code J09 Influenza due to identified zoonotic or pandemic influenza virus and the accompanying common diagnostic term Avian (Bird) Flu have been added to the CED-DxS. The CED-DxS v8.3 will be available for use April 1, 2025.

Use J09 to classify influenza due to influenza A/H5N1 virus, as outlined in this bulletin.

The CED-DxS is used to capture ED Discharge Diagnoses (NACRS data element 137). 

Send your questions about the CED-DxS to nacrspicklists@cihi.ca.

For further clinical information, see Avian influenza A(H5N1): Symptoms and treatment (Government of Canada) or Influenza (avian and other zoonotic) (World Health Organization).