Background
The ongoing outbreak of H5N1 highly pathogenic avian influenza (HPAI) has recently spread from Asia to Africa and Europe, posing an actual public threat as HPAI can occasionally infect humans. Ducks play a major role in the epidemiology of avian influenza because wild waterfowl, including ducks, constitute the natural reservoir of all subtypes of influenza A virus. Experimental infection of ducks with recent isolates indicates a longer shedding period and a selection for lower virulence variant, suggesting that duck has become the “Trojan horse” of Asian H5N1 Avian Influenza (AI) (Hulse-Post et al., 2005).
Although biosecurity is the first line of defence against HPAI, strategic use of vaccination is clearly recognized as a tool to help eradicate HPAI in an infected country. Most studies evaluating the efficacy of AI vaccines have been performed in chickens, and duck studies have been relatively rare. Existing inactivated AI vaccines are less immunogenic in ducks than in chickens and must generally be administered twice to be fully efficient; furthermore, there is no commercially available DIVA test to monitor AI infection in birds vaccinated with this type of vaccine. Therefore, highly efficient, cost-effective, DIVA-compatible AI vaccines for ducks are greatly needed.
In this specific context, live vector-based vaccines hold the greatest promise and are one of the most effective options. Indeed, some live recombinant vector-based AI vaccines have shown excellent results in chickens, but they are not necessarily adapted for use in ducks. Expected advantages of this type of vaccine include administration at a younger age, mass administration, rapid onset of immunity, and compatibility with the DIVA strategy.
The NOVADUCK project is designed to demonstrate and exploit the potential of live vector vaccines to develop a new generation of highly efficient and cost-effective AI vaccines for ducks and therefore could contribute to reduce AI from the ecosystem.
