Author
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Swayne, David |
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Submitted to: International Symposium on Vaccines for OIE List A and Emerging Animal Diseases
Publication Type: Abstract Only Publication Acceptance Date: 6/2/2002 Publication Date: 9/16/2002 Citation: Swayne, D.E. 2002. Vaccines For Avian Influenza. International Symposium on Vaccines for OIE List A and Emerging Animal Diseases. Interpretive Summary: Technical Abstract: Various vaccine technologies have been shown experimentally to be effective for immunization against AI and include conventional inactivated oil-based whole AI virus, vectored virus, subunit protein and DNA vaccines. This protection is based upon antibodies produced against the surface glycoproteins, principally the hemagglutinin, but also the neuraminidase. This protection is specific only for individual subtypes of hemagglutinin (H1-15) and neuraminidase (N1-9) proteins. Avian influenza vaccines protect chickens and turkeys from clinical signs and death, and reduce respiratory and intestinal replication of a challenge virus containing homologous hemagglutinin protein. Many of the vaccines are effective if given by single injection and provide protection for greater than 20 weeks. Protection has been demonstrated against both low and high doses of challenge virus. Furthermore, AI vaccines have been shown to provide protection against homologous field viruses with over 10.6% difference in hemagglutinin sequence homology and isolated over 29 years. Currently, inactivated whole AI virus vaccines and a fowl pox-vectored vaccine with AI H5 hemagglutinin gene insert are used commercially in various countries of the world. These vaccines have economic and intense labor disadvantages associated with parenteral administration. However, a recombinant Newcastle disease virus vaccine with an AI hemagglutinin gene insert shows promise as a low cost, mass administered aerosol vaccine. Critical for the use of vaccines in the field is the ability to differentiate vaccinated birds from birds exposed to the field virus. Differentiation is necessary for outbreak surveillance and trade. The use of AI vaccines varies with individual countries and for different AI virus subtypes |
