avian influenza

noun

variants or avian flu

: highly variable influenza A of birds caused by any of several subtypes of the causative orthomyxovirus (Alphainfluenzavirus influenzae) of which some strains have been or may be transmitted to other vertebrates including humans especially after undergoing mutation

Most cases of avian influenza infection in humans have resulted from contact with infected poultry (e.g., domesticated chicken, ducks, and turkeys) or surfaces contaminated with secretion/excretions from infected birds.

—The Tennessee Tribune

compare bird flu

Examples of avian influenza in a Sentence

Recent Examples on the Web

Over the past quarter century, the powerful, highly contagious form of avian influenza that hit Universal Ostrich Farms has spread from poultry to wild bird populations around the globe. — J. B. MacKinnon, Harpers Magazine, 22 Sep. 2026

This is also some good press for the species, which has been rocked by avian influenza outbreaks across North American nesting sites in the past few years. — New Atlas, 21 Sep. 2026

Frontier models raise stakes A second case involved research into highly pathogenic avian influenza. — Aamir Khollam, Interesting Engineering, 10 Sep. 2026

According to the report, Secret World typically avoids waterbird rescue because of the risk of avian influenza, commonly known as bird flu, spreading through its center and affecting the rest of the wildlife hospital. — Moná Thomas, PEOPLE, 9 Sep. 2026

Word History

First Known Use

1965, in the meaning defined above

Rhymes for avian influenza

• parainfluenza
• cadenza

Medical Definition

avian influenza

noun

variants or avian flu

: influenza of birds that is caused by any of several subtypes (such as H5N2 or H7N7) of an orthomyxovirus (Alphainfluenzavirus influenzae) of which some strains have been transmitted to other vertebrates including humans especially after undergoing mutation

More than 100 species of wild waterfowl have been identified as natural, usually asymptomatic hosts of a variety of avian influenza … subtypes.

—Discover

Bird flu, or H5N1 avian influenza, has been circulating across North America since 2022, infecting birds, livestock, wildlife, pets, and humans. Despite 70 documented human cases, there are no known instances of human-to-human transmission—but some scientists are starting to worry that it's only a matter of time.

—Catherine Caruso, Harvard Medical School

called also fowl pest, fowl plague

see bird flu