Most strains of bird flu (or avian influenza to give it its scientific name) are relatively harmless to their natural bird hosts and do not infect humans - this sort is known as low pathogenic avian influenza (LPAI).
Enamik linnugripi tüvedest on looduslike kandjate jaoks suhteliselt ohutud ja ei nakata inimesi. Seda viiruse alatüüpi nimetatakse vähepatogeenseks linnugripiks (LPAI).