Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2005
Publication Date: 4/7/2005
Citation: Bublot, M., Swayne, D.E., Selleck, P., Montiel, E., Pritchard, N., Lee, M. 2005. Trovac AIh5, an avian influenza fowlpox vector vaccine, as an alternative vaccine for hatcheries. [abstract]. In: Proceedings of OIE/FAO International Scientific Conference on Avian Influenza, April 7-8, 2005, Paris, France. p.68.
Technical Abstract: Inactivated vaccines are the most widely used vaccines in avian influenza (AI) controlled vaccination programs but there is currently no serology test commercially available that can differentiate infected from vaccinated birds (DIVA test). TROVAC AI H5, a fowlpox recombinant expressing the hemagglutinin of an H5 isolate, has received a conditional license in US in 1998 and is used since then in Mexico, Guatemala and El Salvador. More than one billion doses of TROVAC AI H5 have been used so far with no reported adverse reactions. This vaccine protects chickens against mortality and morbidity and significantly decreases shedding after challenge with a wide panel of H5-subtype AI strains. It was recently found to provide 100% protection against mortality/morbidity induced by challenge with recent Asian highly pathogenic H5N1 isolates and reduced challenge virus shedding from respiratory and gastrointestinal tracts by 2.5-4.5log10 of virus. TROVAC AI H5 is fully active in maternal antibody positive 1 day old broiler chickens from breeder hens vaccinated with killed AI and/or fowlpox. However, after placement of chickens in the field, fowlpox vaccination or natural infection interferes with TROVAC AI-induced immunity. Vaccinated birds with TROVAC AI H5 will develop antibodies detectable by the HI test using the appropriate antigen. However, they will not produce antibodies against matrix/nucleoprotein detectable by common serological tests such as AGP and ELISA, which therefore can be used as DIVA tests. Another advantage of TROVAC AI H5 over inactivated vaccine is that it is fully efficacious when administered once in one day-old bird, and it is compatible with Marek's disease vaccination. These features make TROVAC AI H5 the ideal vaccine to be used in hatcheries.