For the first time, researchers have been able to develop a vaccine virus that it able to protect ducks against both Duck enteritis virus (DEV) and avian influenza (AI).

DEV infects ducks, geese and swans, causing mortality rates of up to 100%. Vaccines are widely used to reduce the impact of DEV, and have recently been used for delivering vaccine components of other viruses such as AI.

Domestic duck populations in southeast Asia play a key role in maintaining the reservoir of severe bird flu strains and allow infection to spill over into chickens, making ducks important targets for vaccination campaigns.

As with human flu, bird flu vaccination is complicated by the hundreds of potential strains, with seasonal variations determining which vaccine should be used.

Professor Munir Iqbal at The Pirbright Institute has been able to insert protective AI virus genes into the DEV vaccine by using a method of CRISPR/Cas9 gene editing that allows higher rates of gene insertion.

This gene editing technique enables the rapid generation of vaccines that can protect against DEV whilst keeping up with the changing circulating flu strains.

Professor Iqbal said: “This is the first time this CRISPR/Cas9 method has been applied to duck enteritis virus and is an exciting step forward in the rapid development of bird flu vaccines. Vaccines that protect ducks against DEV as well as severe forms of avian flu will reduce production losses for duck farmers, safeguard other poultry species against flu infection and lower the risk of transmission to humans.”

DEV is increasingly being used to deliver protective genes to birds due to its large genome size, making it easy to manipulate. The method’s design allows its application to different genes and viruses, opening up the possibility that other diseases can be tackled rapidly using this system.

The vaccine is now ready for registration, and collaborations with pharmaceutical companies are being sought in order for the vaccine to be commercialised.