What to Know About the H5N9 Bird Flu

In late January, scientists at the World Organization for Animal Health (WOAH) reported the first cases of H5N9 avian influenza in the U.S., on a duck farm in California. The latest strain isn’t a surprise, say public-health experts, since influenza takes different forms in different species and is constantly mutating. But the appearance of H5N9 … Read more