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Submitted to: Animal Health Research Reviews
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/9/2005 Publication Date: 6/1/2005 Citation: Lee, C.W., Suarez, D.L. 2005. Avian influenza virus: prospects for prevention and control by vaccination. Animal Health Research Reviews. 6(1):1-15. Interpretive Summary: Avian influenza is a virus that can cause serious disease in poultry. On rare occasions these viruses may also infect humans. Therefore, it is important for both human and animal health to control these outbreaks. One method of control is the use of vaccines. Vaccinated birds are generally protected from disease, but the birds can still become infected with the virus and shed virus into the environment. A good vaccine will allow little shedding of virus. A poor vaccine will allow a lot of virus to be shed. By a combination of animal and laboratory studies, it can be determined which vaccines will perform well in the field. The procedures are similar to how human influenza vaccines are selected every year. The availability and use of effective vaccines can be a valuable tool in controlling outbreaks of avian influenza. However, effective control measures must also include quarantines, surveillance, and good biosecurity. Technical Abstract: Like many other RNA viruses, the success of influenza is associated with the virus' ability to undergo antigenic changes. For these reason, human influenza vaccines are evaluated every year to update the vaccine formulation to include vaccine seed that is more similar to currently prevailing strains. In contrast, broad subtype-specific immunity has been observed for avian influenza (AI) vaccines through experimental and field experience. Poultry are usually naïve to influenza virus due to their short production lives, and vaccination has rarely been used for the long-term control of AI. This has likely resulted in less immune selection pressure on the AI virus as compared to human influenza virus, and may partially explain the broader protection of AI vaccine in poultry. However, our recent findings indicate antigenic drift away from the vaccine strain, which has not been observed in AI virus, can occur in poultry. Thus, vaccination can lead to the evolution of antigenically divergent strains. However, it is also possible to control and eradicate the virus by judicious use of vaccination coupled with strong surveillance program. This paper discusses the effectiveness of currently available AI vaccines and suggests the ideal use of the vaccine even with antigenic drift of the virus. |
