As the U.S. awaits word on whether federal regulators will OK a genetically modified salmon, there’s news–and more controversy–about GM chickens developed by researchers at the universities of Cambridge and Edinburgh.

First described in the journal Science, the transgenic chickens cannot transmit avian influenza virus (H5N1) to other chickens. Such a trait might be able to halt the bird outbreaks that can wipe out poultry, especially in developing countries, as well as reduce the risk of flu epidemics among humans, the scientists say. 

To block transmission of H5N1, chickens were genetically engineered to act as a sort of “firewall” in the flock, according to a description in Nature News. Bryan Walsh, in Time, explains the process this way:  “(the researchers) identified a gene that could make birds produce a piece of RNA that acts as a decoy to polymerase, an enzyme that is vital for viral replication. Rather than binding with the virus’ genome, polymerase attaches itself to the decoy gene, preventing the virus from being able to replicate itself and spread.”

In a prepared statement, the study’s lead author Dr. Laurence Tiley, from the University of Cambridge Department of Veterinary Medicine, called the genetic modification “a significant first step along the path to developing chickens that are completely resistant to bird flu.” 

Co-author Helen Sang, a geneticist with the Roslin Institute at the University of Edinburgh, said, “This work could also form the basis for improving economic and food security in many regions of the world where bird flu is a significant problem.”

Sang also noted, “Genetic modification could be more effective than vaccination. You wouldn’t need to change the way you tackle each disease.”

Millions of poultry flocks have had to be destroyed to quell bird flu outbreaks in Asia and the Middle East in the past seven years.  While bird-to-human transmission is rare, it can be extremely lethal. The World Health Organization says there have been 516 avian flu infections with 306 fatalities since 2003.

Don’t expect to see production of flu-blocking GM chickens any time soon. That would require regulator approval as well as consumer acceptance, both significant hurdles. Besides, the researchers say the study was intended to prove a concept. 

Still, reaction to the research was predictable, from those who consider GM crops and animals inherently unsafe, and from those who wonder if genetic modification and other biotechnology may help safely feed a growing world.

Peter Melchett, policy director for the Soil Association, a UK organic farming advocacy group, said in a website statement: “Keeping animals cramped together in inhumane factories encourages the spread of diseases such as bird flu and swine flu. This GM fantasy simply tries to cover up for flawed farming practice.  

“Experience with GM crops shows how quickly resistant super-weeds and new insect pests have developed, despite promises from the GM industry that this could not happen. Viruses are some of the most rapidly evolving organisms on earth, and they could rapidly evolve resistance to the GM chickens.”

And he added: “In a race to develop new strains, viruses would get there faster than new breeds of GM chickens could be produced. Viruses could even evolve to become more virulent in response to the GM challenge, posing a greater threat to human health.”

Douglas Kell, chief executive of the UK’s Biotechnology and Biological Sciences Research Council, which backed the study, said in a prepared statement, “Infectious diseases of livestock represent a significant threat to global food security and the potential of pathogens, such as bird flu, to jump to humans and become pandemic has been identified by the government as a top-level national security risk.” 

Walsh, writing in Time, mused whether “If we can protect ourselves from the next flu pandemic by tweaking our birds, the benefits might be worth the Frankenstein factor.”