RNA technology platform may selectively stop production of nucleic acids that cause disease in animals.

POULTRY disease is an international issue, whether the outbreak is close to home or in developing countries, where it can be a particularly costly problem.

Developing animals resistant to disease may be one of the long-term solutions to disease outbreaks, and University of Georgia researchers in the Regenerative Bioscience Center have spent the last four years gathering data that could make the process a reality, according to an announcement from the university.

The team, which includes Steven Stice and Franklin West in the University of Georgia's College of Agricultural & Environmental Sciences and Claudio Afonso at the Southeast Poultry Research Laboratory of the U.S. Department of Agriculture's Agricultural Research Service, used a technology platform called shRNA -- single strands of RNA that fold back on themselves -- to selectively stop the production of nucleic acids that cause disease, such as the Newcastle disease virus in poultry.

Newcastle disease is a worldwide problem caused by one of the most deadly of all viruses that spreads among birds. Although, exotic Newcastle virus, the most devastating form of the virus, has been eradicated in the U.S. and Canada, it was found in the southwestern U.S. as recently as 2003-04. The milder forms of Newcastle are kept under control by using vaccines.

The research team's tooling process for enhancing disease resistance, published recently in the Journal of the International Alliance for Biological Standardization, is potentially a much better method of disease protection than vaccination because it introduces permanent genetic resistance that is transmittable to a bird's offspring, the researchers said. In contrast, many vaccines provide protection for a given period of time and must be re-administered periodically.

"With this technology, we can target specific regions used by the Newcastle disease virus that are critical for its survival," said Stice, a Georgia Research Alliance eminent scholar and director of the Regenerative Bioscience Center. "Preventing these lethal viruses from replicating in individual chickens may, in the end, reduce the overall level of virus transmission from one chicken to the next."

Multiple types of animals and disease could be targeted. This technology could also be applied to avian and swine influenzas.

"Ultimately, you could have birds that are both avian influenza resistant and Newcastle disease virus resistant," West said. "Theoretically, you may never have to vaccinate again."

Organized distribution of vaccine products can present problems, especially in countries where farmers may not have a refrigerator or other means to store the vaccines at the appropriate temperature. This is particularly true in rural areas where backyard flocks may be a farmer's main source of income.

Shipping disease-resistant chickens produced in the U.S. could be the best possible solution for such countries, Stice said.

"We've taken many years to prove that this technology is viable, and we're now ready to expand our work to the next stage," he said.

The study, "Delayed Newcastle Disease Virus Replication Using RNA Interference to Target the Nucleoprotein," is available at www.sciencedirect.com/science/article/pii/S1045105615000275.

Volume:87 Issue:25