Can avian influenza spread to humans?
Although rare, the H5N1 strain has spread from birds to humans, where it has caused severe illness and death. Exactly how humans become infected from birds is not known. Research has shown that the risk of spread of H5N1 infection from birds to humans is greatest in persons having close contact with live, infected poultry. Sustained human-to-human transmission of H5N1 has not occurred.
