In animals, the avian influenza symptomatology varies both in relation to the viral strain involved in the infection and to the species affected. In birds, in particular, the infection has a benign course, if caused by low pathogenic viruses belonging to all the H subtypes ( LPAI - Low Pathogenic Avian Influence ). The disease caused by LPAI virus is localized and characterized by respiratory and enteric symptoms, often associated with general malaise, tearing and reproductive abnormalities in farm animals (eg egg changes and decreased egg laying).
In contrast, some viral strains belonging to subtypes H5 and H7 can cause high pathogenic avian influenza ( HPAI - High Pathogenic Avian Influence ), a always systemic and serious disease, associated with high mortality between some species of wild and domestic birds. The most evident symptoms are in the nervous system, with depression of the sensory, backward rotation of the head and paralysis of the wings.
