Submitted to: International Symposium on Avian Influenza
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/2014
Publication Date: 7/3/2014
Citation: Pantin Jackwood, M.J., Swayne, D.E. 2014. Prevention, control and eradication of avian influenza including the use of vaccines [abstract]. International Symposium on Avian Influenza, July 3-4, 2014, Leon, Guanajuato, Mexico. CDROM.
Technical Abstract: Avian influenza (AI) is one of the most important diseases affecting the poultry industry worldwide. The AI virus can cause a range of clinical disease in poultry. AI viruses that cause mild disease with low mortality are termed low pathogenic avian influenza (LPAI) viruses. Viruses that replicate systemically and cause severe disease and mortality are referred to as highly pathogenic avian influenza (HPAI) viruses. AI remains a difficult disease to control because of the highly infectious nature of the virus and the interface of domestic and wild animals, and understanding of the disease and its transmission is important for control of the virus. The most effective strategy for dealing with avian influenza includes: early detection and early warning, rapid confirmation of suspected infections, rapid and transparent notification, and rapid response, including containment, management of poultry movement, zoning and compartmentalization, humane stamping out, and vaccination where appropriate. Animal health surveillance is essential for early detection and warning of avian influenza, with biosecurity representing the first and most important means of preventing AI infections in poultry. Stamping-out without vaccination has been the preferred method for HPAI control and eradication used successfully in 27 HPAI epizootics. Vaccination can be used as a tool for supporting eradication programs by increasing the resistance of birds to field challenge and by reducing the amount and duration of virus shed in the environment, but critical to the success of a vaccination program to control AI is monitoring flocks for field virus exposure so appropriate measures can be taken. Field outbreaks of H5N1 HPAI have occurred in vaccinated flocks from both failure of the vaccines (i.e. vaccine efficacy) and failure in administration or immune response of the target species (i.e. vaccination effectiveness). Antigenic drift in field viruses has resulted in failure of protection by classic H5 vaccines strains in Mexico, China, Egypt, Indonesia, Hong Kong and Vietnam. This challenge has been met by developing new vaccine strains that provide protection against ever changing AI viruses. To overcome or prevent such failures, an effective AI vaccination program will require: 1) vaccine must be used in the correct type of vaccination program; 2) vaccine must contain antigenically relevant seed strain and vaccine seed strains must be changed as field virus drifts; 3) vaccine must have sufficient antigen content in each dose; 4) a minimum of two vaccinations must be administered and they should be boosted every six months of life; 5) vaccinated populations must be monitored for protective titers with a goal of greater than 80% of birds in a population being immune; and 6) vaccinated populations must have surveillance to find infections, and infected premises should have birds culled.