Epidemiological impact of recent influenza viruses in various countries.
D000956:Antigens, Viral; D004196:Disease Outbreaks / Q000453:epidemiology*; D006801:Humans; D009980:Influenza A virus; D007251:Influenza, Human / Q000453:epidemiology* / Q000401:mortality; D009975:Orthomyxoviridae / Q000276:immunology
D000956:Antigens, Viral