The epidemiology of influenza.
D000818:Animals; D000956:Antigens, Viral; D014644:Genetic Variation; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology* / Q000662:veterinary; D009975:Orthomyxoviridae / Q000235:genetics*; D011995:Recombination, Genetic
D000956:Antigens, Viral