Bird flu virus adapting in mammals raises pandemic concern

Cases of the H5N1 bird flu virus have been detected in Australian children and a new variant found in US cattle, sparking concern over potential human-to-human transmission. Researchers are monitoring changes in the virus's polymerase protein, which could enable it to replicate more efficiently in human cells. While direct risk remains low, any mutation allowing easier spread among people would demand a nervous system-level response for immunity.