Computer models will be built to forecast how Marek’s disease — a highly contagious viral infection affecting chickens — is transmitted from bird to bird and how it evolves to become more harmful, according to The Roslin Institute in the U.K. The models could enable development of effective vaccines and control strategies to prevent outbreaks.
Researchers will also determine the combined effects of vaccination with bird and virus genetics on how viruses spread and evolve to higher virulence, Roslin said in an announcement.
The study will focus on Marek’s disease and infectious bronchitis viruses, which are currently controlled by imperfect vaccines and cost the industry billions of dollars in losses each year.
The study has been awarded £3.1 million by the U.S. National Science Foundation and the U.K. Biotechnology & Biological Sciences Research Council and will be led by Drs. John Dunn and Hans Cheng at the U.S. Department of Agriculture’s Agricultural Research Service. The U.K. component of the study will be led by professor Andrea Doeschl-Wilson and Dr. Sam Lycett at Roslin.
Bird and virus genetics
The effectiveness of current control approaches for each virus, such as vaccines and selective breeding, will be determined by analyzing data from more than 7,000 birds, Roslin said.
Researchers will investigate how the viruses evolve as they are transmitted up to 10 times by comparing the effects in vaccinated versus non-vaccinated chickens and in chickens that differ in their genetic resistance to the virus.
The researchers said they hope to discover common variations in the genetic code of the birds and viruses that are linked to higher virulence and to the ability of the viruses to evade immune surveillance. To achieve this, they will compare the genetic makeup of the most virulent variations of the viruses — those that have been transmitted 10 times — with the original virus that infected the first chickens, Roslin said.
All the data will be fed into computational models that simulate the transmission and evolution of Marek’s disease.
"This is the first study that investigates the combined influence of vaccination, host and viral genetics on how viruses are transmitted and evolve to higher virulence. We hope that our models can inform future control strategies to help tackle the health, welfare and economic burden of Marek’s disease as well as other poultry viruses," said Doeschl-Wilson, personal chair in animal disease genetics and modeling at the Roslin Institute.
Through collaboration with researchers and communities in tropical Africa, the model results will be used to develop strategies for mitigating the impacts of Marek’s disease in tropical African countries, where poultry production plays an important economic role.