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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 8/10/2006 Publication Date: 9/1/2006 Citation: Suarez, D.L. 2006. Influenza virus in poultry. In: Proceedings of the Pre-Emerging Virus Infections, Pasteur/NHRI/CDC Symposium, September 1-3, 2006, Tainan, Taiwan. p. 16. Interpretive Summary: Technical Abstract: Avian influenza virus (AIV) is normally found in wild birds, particularly in ducks and shorebirds, where it does not cause any perceptible clinical disease. However, poultry, including chickens and turkeys, are not normal hosts for avian influenza, but if the virus is introduced it can result in mild to severe disease symptoms. The most severe form of disease is highly pathogenic avian influenza (HPAI), which by definition kills 75% or more of experimentally inoculated chickens. Although 16 hemagglutinin subtypes of avian influenza are known, only some H5s and H7s have the HPAI phenotype. The most severe outbreak of HPAI in recent times has been the Asian H5N1 outbreak. A variant of this virus was first reported in 1996, and the virus has circulated in the region since then. The human and poultry outbreak in Hong Kong was when the H5N1 virus was first recognized internationally to be an issue. Since 2003 the virus has spread beyond Asia, and many countries in Europe and Africa have had outbreaks in wild birds or poultry. Outbreaks of HPAI are usually controlled by a test and slaughter method (stamping out), but this approach works well only when the outbreak is contained early. The Asian H5N1 is now endemic in several countries and is thought to be maintained in the wild bird reservoir, which makes control extremely difficult. Vaccination is being used in several countries for control, and will likely continue until the outbreak is more contained. Vaccination if used as an integrated control program can be useful for the control of AIV. Unfortunately, the virus has spread to many poorly developed countries that lack the veterinary infrastructure to deal with the outbreak, and international assistance is needed to aid the affected countries. |
