Avian Influenza Avian Flu Bird Flu H5N1 Symptoms Flu infections Flu activity Pandemics Transmission Pneumonia 1918 Influenza Pandemic Flu season Complications Flu-like illness Complications of the flu Influenza Cases Flu Shots Antiviral Drugs H5N1 virus Treatments Cross-Species Transmission Genetic Analysis Mutations Risk to Human Health Comparison to Covid-19 History of Avian Influenza Tests and Vaccines Seasonal Flu Preventive Measures Prevention A(H5N2) Human Case H1N1 Influenza Pandemic Avian Influenza (H5N1) Sepsis Influenza Complications Flu Season