Influenza D study raises new spillover questions for veterinarians

Researchers at The Ohio State University report that influenza D virus, a pathogen first identified in animals in 2011 and primarily associated with cattle, replicated efficiently in human airway cells and human lung tissue at levels comparable to seasonal influenza A viruses. The study, published in Proceedings of the National Academy of Sciences and highlighted by Ohio State on April 24, 2026, tested multiple genetically distinct influenza D strains from cattle and pigs, and found they behaved similarly in human respiratory models. The team also found that, unlike influenza A, influenza D did not trigger a strong antiviral interferon response in infected human cells, which could help explain why human infections, if they occur, might be missed or remain subclinical. (news.osu.edu)

Why it matters: For veterinary professionals, the findings add weight to influenza D’s status as a One Health surveillance concern, especially at the cattle-human and pig-human interface. There are still no confirmed active human influenza D cases, but prior CDC-cited and peer-reviewed work has found antibodies in people with livestock exposure, including very high seroprevalence reported among cattle workers in one Florida study. That means veterinary teams, diagnosticians, and herd health programs may need to think of influenza D not just as a bovine respiratory pathogen, but as a virus worth watching for occupational exposure, surveillance gaps, and possible silent spillover. (news.osu.edu)

What to watch: Watch for follow-up surveillance in pigs, cattle, and exposed workers, as well as any attempt to document a confirmed human infection or evidence that circulating strains are changing in ways that could increase adaptation risk. (news.osu.edu)