The spread of type A influenza.
D000956:Antigens, Viral / Q000276:immunology; D006801:Humans; D009980:Influenza A virus / Q000276:immunology; D007251:Influenza, Human / Q000276:immunology / Q000635:transmission*; D012621:Seasons; D013472:Sunlight
D000956:Antigens, Viral