A highly pathogenic strain of avian flu, part of the H5N1 family, is causing concern among health and animal experts due to its ability to affect a wide range of bird species and potentially jump to humans. Initially affecting seabirds and some duck species, the virus's behavior is becoming increasingly unpredictable, with some birds showing no symptoms while transmitting the virus. The virus's rapid spread in British Columbia has led the local health authorities to warn clinicians about the potential for human infection, adding to the global concern over this outbreak. Avian immunologist Shayan Sharif at the University of Guelph highlights the unknowns surrounding the virus's virulence and transmission in different bird species and raises alarm over the recent discovery of the virus in mammals like bears and foxes, potentially signaling a broader jump to other species, including humans.