[What is the source of the influenza virus?].
D000818:Animals; D006168:Guinea Pigs; D006801:Humans; D007251:Influenza, Human / Q000662:veterinary; D009975:Orthomyxoviridae; D013552:Swine; D013553:Swine Diseases; D015047:Zoonoses / Q000382:microbiology