[Natural focus nature of influenza].
D000293:Adolescent; D000818:Animals; D000835:Animals, Wild; D000956:Antigens, Viral / Q000032:analysis / Q000302:isolation & purification; D001717:Birds; D002031:Bulgaria; D002648:Child; D004197:Disease Reservoirs; D004463:Ecology; D014644:Genetic Variation; D006801:Humans; D009980:Influenza A virus / Q000145:classification / Q000276:immunology / Q000472:pathogenicity; D007251:Influenza, Human / Q000453:epidemiology* / Q000276:immunology / Q000382:microbiology; D011995:Recombination, Genetic; D014586:USSR; D014481:United States
D000956:Antigens, Viral
O prirodnoĭ ochagovosti grippa.