Over the past two years, the dangerous H5N1 bird flu has killed millions of wild and farm birds worldwide and spread to animals like seals, sea lions, mink, cats, dogs, skunks, foxes, and a polar bear. However, few humans have been infected, puzzling experts. Dr. Richard Webby from St. Jude Children’s Research Hospital suggests that species-specific differences in infection might explain this. Scientists worry the virus could cause a serious human epidemic, with Dr. Tom Frieden, former CDC director and current head of Resolve to Save Lives, stressing the need for preventive actions.

First detected in birds in 1959, the H5N1 virus gained global attention after a major outbreak in Hong Kong in 1997. It has since mutated and spread rapidly. In the U.S., it has caused outbreaks on dairy farms and among poultry. The U.S. Department of Agriculture has recorded four human infections among farm workers, with the actual number possibly higher. Globally, there have been 15 known human cases, including one death in China in 2022, mainly from direct contact with birds. The virus affects various organs in animals, causing severe symptoms. Researchers like Amy Baker from the USDA are studying why some species are more affected than others. Although cows show milder symptoms, there are concerns that the virus could mutate and become more dangerous to humans, leading to increased monitoring and preparations for future outbreaks.