Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2001
Publication Date: 2/1/2000
Interpretive Summary: Avian influenza (AI) is a disease of poultry caused by a virus. AI has caused outbreaks of disease in poultry worldwide. Previous studies have shown vaccines can be effective at preventing the disease in chickens and can be part of any future comprehensive eradication programs. The purpose of the current study was to determine if three different types of vaccines would provide protection against only a few H5 AI viruses from today or i protection could be against a variety of H5 AI viruses from different genetic backgrounds. The vaccines provided protection against clinical signs and death in chickens given different deadly H5 AI viruses. The vaccines also reduced the ability of AI viruses to infect chickens and reduced the quantity of virus put back into the environment. Our results show that these three vaccine technologies can provide protection against a variety of different deadly H5 AI viruses without the need to change the vaccine strains.
Technical Abstract: Inactivated whole avian influenza (AI) virus vaccines, baculovirus-derived AI haemagglutinin vaccine and recombinant fowl poxvirus-AI heamagglutinin vaccine were tested for the ability to protect chickens against multiple highly pathogenic (HP) H5 AI viruses. The vaccine and challenge viruses, or their haemagglutinin protein components, were obtained from field AI viruses of diverse backgrounds and included strains obtained from four different continents, six different host species and isolated over a 38 year period. The vaccines protected against clinical signs and death, and reduced the number of chickens shedding virus and the titre of the virus shed following a HP H5 AI virus challenge. Immunization with these vaccines should decrease AI virus shedding from the respiratory and digestive tracts of AI virus exposed chickens and reduce bird-to-bird transmission. Although, most consistent reduction in respiratory shedding was afforded when vaccine was more similar to the challenge virus, the genetic drift of avian influenza virus did not interfere with general protection as has been reported for human influenza viruses.