Does the Avian Influenza A/H5N1 virus spread easily from birds to humans?
No. Despite the extension and duration of the outbreaks in animals presenting vast opportunities for animal to human exposure (in particular in areas where backyard flocks are common), the number of human H5N1 avian influenza cases remains very small. It is not presently understood why some people, and not others, become infected following similar ‘high risk’ exposures. Family genetic predisposition might play a role as a blood relationship has been found in most of the clusters of cases.
