Changes in a viral protein called VP4 could explain differences in severity between strains of infectious bursal disease virus (IBDV), according to a new study from The Pirbright Institute.
The discovery, published in Frontiers in Cellular and Infection Microbiology, could lead to a vaccine for the virus, which can cause high mortality in chicken flocks.
Infectious bursal disease virus (IBDV) is the cause of infectious bursal disease, a highly contagious disease that lowers the immunosuppression of young chickens. Chickens with infectious bursal disease are highly susceptible to other secondary infections.
“In the 1980s, a so-called “very virulent” (vv) IBDV strain emerged that could kill up to 60% of some flocks. This strain has now spread across the globe. There are several vaccines licensed for use against IBDV, but we are now seeing more and more vaccine failures, for reasons that we don’t fully understand. This means IBDV is a big concern for commercial poultry units,” explained Andrew Broadbent, head of the Birnaviruses Group at The Pirbright Institute.
“My group is doing research to improve the control of IBDV through improving surveillance, vaccine design, and vaccine regimens. We are also studying how IBDV replicates inside chicken cells, and how it damages the immune system.”
The study
Researchers at The Pirbright Institute compared a very virulent strain to a classic strain of IBDV, revealing that the very virulent strain more effectively stopped the antiviral response of infected cells. The findings suggest that genetic variations in the VP4 protein contributed to differences in IBDV virulence.
The researchers hope to use this information to create a vaccine for IBDV.
“If we insert the VP4 from a weak strain into a vv strain, it may weaken the virus such that it does not induce disease but it still induces immune responses, and it may therefore make a good vaccine. Alternatively, we could insert the VP4 protein from a vv strain into an overly weak vaccine that doesn’t work very well to potentially make it more effective,” Broadbent said.
This study was funded by the Biotechnology and Biological Sciences Research Council (BBSRC), part of UK Research and Innovation (UKRI).
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