New step toward eradication of H5N1 bird flu

A SIGNIFICANT significant step in the fight against H5N1, an often fatal strain of avian influenza,  with a new tests that distinguishes between births that have been vaccinated against the “bird flu” and those that have been naturally infected. The development of the new DIVA test (differentiation of infected from vaccinated animals) was led by scientists from the University of Adelaide.

H5N1 bird flu, which is widespread in the poultry populations of Southeast Asia, particularly Indonesia and Viet Nam, causes global concern because of its possible transmission to humans and the threat of a pandemic if it mutates to a form that can be easily passed from bird to human then human to human. The research has been published in PLOS ONE.

“Avian flu is 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,” said project leader Dr. Farhid Hemmatzadeh, senior lecturer in Virology in the School of Animal and Veterinary Sciences at the Roseworthy campus of University of Adelaide.

While outbreaks in birds are largely being controlled by vaccination,  the inability of distinguishing between vaccinated and naturally infected birds has been a major challenge. This has prevented tracking the virus, which can still circulate in vaccinated birds and may mutate to new strains under what is called vaccination pressure.

“These birds that have been vaccinated, but still have live naturally infected H5N1 virus in their systems are the main source of emerging strains of the virus – and these new strains may be even more dangerous to birds or humans,” explained Dr. Hemmatzadeh.

Since the first outbreak of H5N1 avian influenza virus in 2004, the development of a reliable DIVA test has been global priority. The test uses a particular viral protein called Matrix protein 2 that reacts differently with blood serum from vaccinated or infected animals. 

“With this new, more sensitive, test we can identify these vaccinated birds with live virus and prevent the escape of any mutant strains. This is essential if we want to prevent pandemics developing from this virus and eventually eradicate this disease,”Dr. Hemmatzadeh said.

The researchers, including the University of Melbourne, CSIRO and Indonesian organizations, are carrying out large surveillance programs in poultry farms across Indonesia. The research is funded by the Australian Centre for International Agricultural Research (ACIAR).