01/31/2025

Another Strain Of Bird Flu Discovered In California

A large group of white-haired ducks in the duck farm.
Credit: Shutterstock

This week, the World Organization for Animal Health reported that it had been notified by the USDA that a November outbreak of highly pathogenic avian influenza on a California duck farm was caused by a strain not before seen in the United States: H5N9. The dominant bird flu strain circulating currently, H5N1, has led to massive culling of bird flocks, has infected dairy cattle, and has killed almost 500 people around the world since 2003. The US reported its first human death from bird flu earlier this month.

Experts stressed that the new strain did not itself appear to be an immediate human threat. But the rise of a new strain is troubling and points to the risk of a viral phenomenon known as “reassortment,” in which different viruses mingled in a host can sometimes exchange bits of viral code, forming new strains.

SciFri’s Charles Bergquist joins Flora Lichtman to talk about H5N9 and other stories from the week in science, including a spacewalk that was meant to include a search for microbes on the outside of the International Space Station, a possible positive side effect of scratching an itch, and the discovery of 66 million-year-old fossilized vomit.


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Segment Guests

Charles Bergquist

As Science Friday’s director and senior producer, Charles Bergquist channels the chaos of a live production studio into something sounding like a radio program. Favorite topics include planetary sciences, chemistry, materials, and shiny things with blinking lights.

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Meet the Producer

About Flora Lichtman

Flora Lichtman is a host of Science Friday. In a previous life, she lived on a research ship where apertivi were served on the top deck, hoisted there via pulley by the ship’s chef.

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