When it comes to the potential of H5N1 avian flu, otherwise known as bird flu, picking up mutations that may lead to human-to-human spread, that "train has already left the station," warns one infectious disease expert.

Q&A: From people avoiding wild birds to farmers protecting their animals, Kent State epidemiologist Dr. Tara Smith shares tips on bird flu prevention.

Bird flu cases continue to spread across the country and the world, leaving many worried about their health as outbreaks increase in poultry and wild birds. The CDC said the public health risk is currently low,