How does the avian influenza virus spread in birds?
Avian influenza is primarily spread by direct contact between healthy birds and infected birds, and through indirect contact with contaminated equipment and materials. The virus is excreted through the feces of infected birds and through secretions from the nose, mouth and eyes.
Contact with infected fecal material is the most common of bird?뱓o?밷ird transmission. Wild ducks often introduce low pathogenic avian influenza into domestic flocks raised on range or in open flight pens through fecal contamination. Within a poultry house, transfer of the highly pathogenic avian influenza virus between birds also can occur via airborne secretions. The spread of avian influenza between poultry premises almost always follows the movement of contaminated people and equipment. Avian influenza also can be found on the outer surfaces of egg shells. Transfer of eggs is a potential means of transmission. Airborne transmission of virus from farm to farm is highly unlikely under usual circumstances.