News - EUROPA - Animal Health & Welfare - Animal Diseases - Avian Influenza - Introduction

Avian Influenza (AI) or "Bird Flu" is a highly contagious viral infection which can affect all species of birds and can manifest itself in different ways depending mainly on the pathogenicity of the virus involved and on the species affected.

Influenza infections in birds are divided in two groups on the basis of their ability to cause disease:

Highly Pathogenic Avian Influenza (HPAI): causing serious disease with high mortality (up to 100%) ? notifiable to the OIE;
Low Pathogenic Avian Influenza (LPAI): causing generally a mild disease ? not notifiable to the OIE.
Even if in certain cases LPAI virus may mutate in HPAI virus and cause a serious disease, the two infections are well distinct and should not be confused.

While domestic birds are generally highly susceptible to the clinical manifestation of the disease, wild birds, and especially waterfowls, are usually naturally resistant and often don?t show any clinical sign. Therefore, wild waterfowl represent a natural reservoir for these viruses and can be responsible for the primary introduction of infection into domestic poultry.

EUROPA - Animal Health & Welfare - Animal Diseases - Avian Influenza - Introduction