Public health experts are continuing to raise the alarm about a highly contagious avian disease that has quickly spread across the globe. The virus — known as H5N1 or colloquially, bird flu — has been causing significant problems over the past year, spawning a "panzootic," or a pandemic among animals. The evolving disaster is contributing to commercial egg shortages and killing large amounts of wild and factory farmed animals — and a few hundred humans.
There have 873 human H5N1 cases since 2003, but an estimated 53 percent have been fatal.
