Related by context. Frequent words. (Click for all words.) 53 influenza pandemics 51 pandemic H#N# 51 outbreaks 50 pandemic influenza 50 pandemics 49 epidemics 46 pandemic 46 H#N# viruses 45 viral strains 45 virulent strains 45 influenza strains 45 bird flu outbreaks 44 influenza virus 44 influenza pandemic 44 influenza viruses 43 Pandemics 43 pandemic flu 43 influenza 43 highly pathogenic avian influenza 42 smallpox outbreak 42 seasonal influenza vaccines 42 pandemic influenza vaccine 42 cholera outbreaks 42 viruses 41 outbreak 41 avian influenza viruses 41 flu pandemics 41 avian flu 41 highly pathogenic strain 41 zoonotic 41 epidemic 41 H#N# avian flu 41 flu pandemic 40 H#N# pandemic 40 H#N# pandemic influenza 40 borne diseases 40 H#N# influenza virus 40 Influenza viruses 40 poultry flocks 40 flu viruses 40 coronaviruses 40 species extinctions 39 serotypes 39 flu strains 39 H#N# flu pandemic 39 pandemic H#N# influenza 39 multidrug resistant 39 zoonotic diseases 39 vaccines 39 influenza vaccine 39 natural disasters 39 milder winters 38 avian flu outbreak 38 H#N# swine flu 38 pandemic strain 38 bird flu epidemic 38 antimicrobial resistance 38 H#N# avian influenza 38 parasitic diseases 38 heatwaves 38 respiratory viruses 38 floods droughts 38 seasonal influenza vaccine 38 flu virus 38 bacterial strains 38 pneumococcal vaccines 38 mosquito borne 38 antibiotic resistant infections 38 A/H#N# influenza 38 H#N# strain 38 infections 38 avian influenza 38 infecting humans 38 H#N# Swine Flu 38 vector borne diseases 37 populations 37 antibiotic resistant strains 37 Anthony Fauci director 37 parasitic infections 37 infectious diseases 37 noroviruses 37 HPAI 37 foodborne pathogens 37 smallpox 37 disasters 37 Avian influenza 37 viral diseases 37 influenza vaccines 37 H#N# influenza 37 influenza A/H#N# 37 resistant strains 37 avian influenza virus 37 reassortment 37 cataclysms 37 vaccine 37 Avian flu 37 virologists 37 pneumococcal 37 bird flu pandemic 36 CDAD 36 pertussis whooping cough