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Data update—Infectious Diseases

April 15

Track confirmed human cases of H5N1 “bird flu” since 1997

Avian influenza A (H5N1), often referred to as “bird flu”, is a subtype of influenza virus that infects birds and mammals. In rare cases, humans can also be infected.

Public health experts consider H5N1 a potential pandemic threat and monitor it closely, especially through the WHO Global Influenza Programme (GIP).

Since 2003, the WHO has recorded nearly 1,000 confirmed human infections with H5N1 across 25 countries, causing more than 450 deaths.

Keep in mind that the true burden of infection is not fully known, because only a small fraction of potential cases are tested by labs to confirm whether they have influenza and to identify their strain.

I've updated our chart with the latest data from the WHO GIP (obtained via the US CDC), covering monthly reported cases since 1997. We update this data quarterly.

Explore the updated data in our interactive chart
Column chart of monthly reported human cases of H5N1 by world region from 1997 to 2026 where most cases cluster in Asia in the early 2000s, there is a very large spike in Africa around mid-2014, and a smaller spike in North America in early 2026. Data source: WHO, Global Influenza Programme (2026). License: CC BY.
Lucas Rodés-Guirao