Influenza is a large family of different viruses, some of which affect humans and many of which affect other animals and especially birds.
<img style="border-right:1px solid;border-top:1px solid;border-left:1px solid;border-bottom:1px solid" alt=" Delci virusa aviarne influence H5N1, transmisijski elektronski mikrograf " src="http://staging.ecdcdmz.europa.eu/en/healthtopics/avian_influenza/PublishingImages/1009_influenza_avian_startpage_pic.jpg" align=right border=1> Influenca je velika družina različnih virusov – nekateri od njih prizadenejo ljudi, veliko pa jih prizadene druge živali, zlasti ptice.