Professor Zhizhong Cui from Shandong Agricultural University presented data which showed that sporadic outbreak of avian flu could coincide with infections by immunosuppressive viruses. The avian flu outbreaks can happen in populations of farm chickens where all the chickens are vaccinated against avian flu.
These findings were supported by experimental data showing that several immune suppressive viruses have the ability to weaken the immune protection in vaccinated chickens. With a weakened immune defence the chickens are vulnerable to avian flu virus.
The conclusion of this new finding is that the current vaccination programmes alone can not be guaranteed to control avian flu in commercially farmed chickens. Various immune suppressive viruses are widespread in chicken farms and have the ability to make the chicken vulnerable to avian flu even after vaccination. The prevalence of immunosuppressive virus infection in chicken is not well known and should be studied in more detail. There may be a need for a new vaccination strategy targeting a range of viruses in order to control avian flu.
