What is Avian Influenza (AI)?

Avian influenza (AI), caused by the influenza virus Type “A”, can affect several species of food producing birds (chickens, turkeys, quails, guinea fowl, etc.), as well as pet birds and wild birds with some strains resulting in high mortality rates. The virus has also been isolated from mammalian species including humans, rats and mice, weasels and ferrets, pigs, cats, tigers and dogs.

AI viruses are not new. There are many descriptions of historical outbreaks of AI in domestic poultry throughout available literature. There are many strains of AI viruses and generally can be classified into two categories: low pathogenic (LPAI) that typically causes little or no clinical signs in birds and highly pathogenic (HPAI) that can cause severe clinical signs and/or high mortality in birds.

The Asian origin highly pathogenic H5N1 strain of the AI virus has attracted much attention over the last few years because of significant outbreaks globally in domestic and wild birds. Concern is raised because of the degree of virulence not only in poultry but also in wild birds as well as the ability to infect mammalian species. While AI viruses are generally highly species specific, the highly pathogenic H5N1 AI virus has also infected humans.

Low pathogenic strains of AI H5N1 virus exist but do not produce significant clinical signs in birds. Avian influenza is a disease listed under the World Organization for Animal Health (OIE) Terrestrial Animal Health Code – 2006 (Article 2.1.1.3). Notifiable avian influenza includes two particular subtypes, H5 and H7 that must be reported to the OIE (as per Chapter 1.1.2. – Notification of Diseases and Epidemiological Information).

source: http://www.oie.int/eng/en_index.htm