For the first time, researchers -- led by professor Munir Iqbal at The Pirbright Institute in the U.K. -- have been able to insert protective avian influenza virus genes into the duck enteritis virus (DEV) vaccine by using a method of CRISPR/Cas9 gene editing that allows higher rates of gene insertion.
According to an announcement from the U.K.'s Biotechnology & Biological Sciences Research Council (BBSRC), which funded the project, the development makes the process more efficient, and the resulting vaccine virus is able to protect ducks against both DEV and avian influenza.
DEV, which infects ducks, geese and swans, causes mortality rates of up to 100%. Vaccines are widely used to reduce the effects of DEV and have recently been utilized for delivering vaccine components of other viruses such as avian influenza. Domesticated duck populations in Southeast Asia also play a key role in maintaining the reservoir of severe avian influenza strains and allow infection to "spillover" into chickens, making ducks important targets for vaccination campaigns, BBSRC said.
As with human flu, avian flu vaccination is complicated by the hundreds of potential strains, with seasonal variations determining which vaccine should be used. The gene editing technique, described in the journal Viruses, enables the rapid generation of vaccines that can protect against DEV while keeping up with the changing flu strains that are circulating, the announcement said.
Iqbal, leader of the Avian Influenza group at Pirbright, 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, which makes it easy to manipulate, as well as the narrow range of species it is able to infect, BBSRC said. 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 to commercialize the vaccine. The potential for avian flu to mutate in such a way that makes human-to-human transmission possible is of increasing concern, so vaccinating ducks is an essential strategy for protecting both birds and humans from infection.
The Pirbright Institute is a center of excellence in research and the surveillance of viral diseases of farm animals and viruses that spread from animals to humans. Based in the U.K. and receiving strategic funding from BBSRC, the institute works to enhance the capability to contain, control and eliminate these economically and medically important diseases through highly innovative, fundamental and applied bioscience.