H5N1 Bird Flu Highly Pathogenic Avian Influenza (HPAI) Highly Pathogenic Avian Influenza Transmission Precautions H5N1 Strain Prevention Symptoms H5N1 Virus Highly Pathogenic Bird Flu HPAI Spread Zoonotic Diseases Poultry Biosecurity Measures Cattle Human Risks Pathogenic Avian Influenza Immune System Virus Mutations HPAI H5N1 Transmission Risk Outbreak High Pathogenicity Avian Influenza (HPAI) H5N1 Alpacas Human Case Human Exposure Strains of Influenza Public Health Concerns Impact on Agriculture Public Health Newcastle Disease