Epidemiology Virus Transmission Transmission Pathways H5N1 Virus Disease Transmission Transmission Nipah Virus Transmission Risks Virus Mutation Avian Influenza Bird Flu Virus Evolution Animal-to-Human Transmission Animal Health Pathogens Virus Surveillance Field Mice Rabies-like Viruses Infectious Agents Rabies Virus Pathogen Transmission Genetic Sequencing Flu Viruses Viral Evolution H5N1 Research Bornavirus Transmission of Viruses Influenza Viruses Research on COVID-19 Origins