A new test that can differentiate between birds that have been vaccinated against the H5N1 strain of avian influenza virus or "bird flu" with those that have been naturally infected has been developed by scientists.
The study conducted at University of Adelaide can be a step in the fight against this often fatal strain of avian influenza which is widespread in the poultry populations of South East Asia, particularly Indonesia and Vietnam.
Project leader Dr Farhid Hemmatzadeh, Senior Lecturer in Virology in the School of Animal and Veterinary Sciences at the Roseworthy campus, said that avian flu was on the top list of notifiable diseases of the World Organization for Animal Health (OIE) because of its high economic cost and risk to human health.
Hemmatzadeh asserted that these birds that had been vaccinated but still had live naturally infected H5N1 virus in their systems were the main source of emerging strains of the virus and these new strains may be even more dangerous to birds or humans.
The bird vaccine is made from avian influenza virus which has been killed but still promotes the production of antibodies in the bird protecting it against the live virus. The antibodies prevent the replication of the virus in the bird, but in some cases the virus mutates in a vaccinated bird and can still replicate even with the existing high level of antibodies to the vaccines.
The new DIVA test (differentiation of infected from vaccinated animals) uses a particular viral protein called Matrix protein 2 that reacts differently with blood serum from vaccinated or infected animals. Since the first outbreak of H5N1 avian influenza virus in 2004, the development of a reliable DIVA test has been global priority.
The study is been published in journal PLOS ONE.