Vectored Vaccines for Avian Influenza - By David Swayne, USDA's Agricultural Research Service, Southeast Poultry Research Laboratory - Cases of avian influenza infections of poultry and humans have caused the world to be on alert for a pandemic. ARS veterinary medical officer and laboratory director David Swayne and his team at the Southeast Poultry Research Laboratory in Athens, Georgia, are developing new viral-vectored vaccines to facilitate vaccine efficiency against avian influenza.

A vector is a biological carrier of genes of another pathogen. Vectors such as the turkey herpesvirus, infectious laryngotracheitis virus, and adenoviruses are being used and could allow mass application of vaccine. Development of new vaccines will help to protect birds and humans in the event of an outbreak of avian influenza in the United States. “Mass-application technologies, like a spray or in ovo injection, for new viral or bacterial vector systems will provide economic incentives for adoption over current labor-intensive, manual, individual-bird injection methods used today,” says Swayne.

Swayne and his research team are working with Mount Sinai Hospital in New York to develop a spray vaccine for avian influenza that uses the Newcastle disease virus as a vector. “This combination allows us to use one vaccination that will protect against both avian influenza and Newcastle disease,” says Swayne.

Another collaboration with Merial, Inc., of Athens, Georgia, is using fowl pox as a vector for avian influenza virus, yielding one vaccine that lends protection for both of those diseases. “We are also working with the University of Pittsburgh and Vaxin, Inc., of Birmingham, Alabama, to develop vaccines using adenoviruses as vectors,” says Swayne. The common cold is caused by an adenovirus. The avian influenza gene is inserted into the adenovirus, and the preparation can be injected into individual birds or potentially sprayed onto many birds at one time.

Another advantage of using these types of vaccinations is that vaccinated birds can be distinguished from infected birds. “It is very important to be able to tell the difference between a bird with a natural infection of avian influenza and a bird that has been vaccinated with the virus,” says Swayne. “This differentiation assures international traders that the poultry is not infected with the virus, but rather protected against it.”

Source: USDA Agricultural Research Service - February 2006