The CDC said the patient's sample showed mutations in the hemagglutinin (HA) gene, the part of the virus that plays a key role in it attaching to host...

California, the most populous state, declared an emergency over the H5N1 virus as it spread more widely in dairy herds and after it has infected dozen...

Avian influenza viruses pose a serious public health risk because they are commonly found in animals and have the potential to cause a future pandemic...

Mexico's Health Ministry also said in a statement the source of infection had not been identified.