Poultry vaccination advances obscured by COVID-19's shadow

New ways of protecting poultry from disease of economic importance continue to be developed

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JurgaR | iStockPhoto.com
JurgaR | iStockPhoto.com

Nobody can be unhappy about the various COVID-19 vaccine announcements that have filled the headlines over the last 10 days or so. We have probably all become, to varying degrees, armchair vaccination experts.

However, there is a lot of other vaccine research being conducted, including in the poultry industry, that is, perhaps, not getting the attention it deserves.

Groundbreaking ways of understanding more about infectious bronchitis virus (IBV) and preventing infection, for example, along with studies into Marek’s disease, are progressing, even if they are not grabbing headlines.

At the U.K.’s Pirbright Institute, researchers have found new ways of studying IBV strains, many of which are extremely difficult to grow in the laboratory.

Adding the enzyme trypsin to two types of laboratory cell cultures to look at its impact on the growth of three IBV strains, revealed that two of the strains, M41-CK and BeauR, subsequently grew rapidly.

After being grown in cells with trypsin multiple times, M41-CK was able to grow at lower levels without the enzyme, meaning that the virus may have adapted to growth in these cells. The BeauR strain was already able to replicate in these cells but, with the addition of trypsin, it significantly increased its growth levels.

The third IBV strain, 4/91 U.K., was unable to grow in either cell culture, with or without the addition of trypsin, and more research is needed into how trypsin increases IBV growth, and its effects on more strains.

Nevertheless, the study provides a first step in establishing new IBV strains in laboratory cell cultures and could have implications for vaccine development. Instead of growing IBV vaccine viruses in eggs, they could be produced in cells, offering a more reliable and flexible platform for developing the next generation of IBV vaccines.

First of its kind

In what is the first study of the combined influence of vaccination, host and viral genetics on how viruses are transmitted to evolve higher virulence, work at the U.K.’s Roslin Institute is looking at Marek’s disease and infectious bronchitis viruses. It is building computer models that can forecast how Marek’s disease transmits and becomes more harmful.

The model, it is hoped, could enable not only the development of more effective vaccines, but also control strategies to control outbreaks.

The effectiveness of current approaches for Marek’s and infectious bronchitis virus will be determined by analyzing data from 7,000 birds. Researchers will investigate how the viruses evolve as they are transmitted up to 10 times by comparing the effects in vaccinated and non-vaccinated chickens, and in chickens that differ in their genetic resistance to the viruses.

The scientists hope to discover common variations in the genetic code of the birds and viruses that are linked to higher virulence and the ability of viruses to evade immune surveillance.

While the economic impact of disease may be something the general public has only recently become aware of, for the agricultural sector the connection has been ever-present, so developments in poultry vaccination ought to be welcomed as much as they are in any other sector.



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