Research offers new insight on infectious bronchitis vaccination

USPOULTRY and the USPOULTRY Foundation announce the completion of a funded research project at the University of Georgia, Athens, Georgia, in which researchers provide insight on vacation against infectious bronchitis.
Dr. Mark Jackwood and Dr. Brian Jordan at the University of Georgia recently completed a research project that looked at the possible reasons for frequent vaccine failures when broilers are vaccinated with Arkansas infectious bronchitis vaccine. They found the vaccine contains a mixture of subpopulations of viruses, and one of the minor subpopulations is actually responsible for immunizing the birds. Using a hatchery spray cabinet, they showed the limiting factor for immunizing chicks with the vaccine was delivering an adequate dosage of the critical minor virus subpopulation to the chicks. This research may lead to future improvements in the Arkansas infectious bronchitis vaccine.
The project is part of USPOULTRY’s comprehensive research program encompassing all phases of poultry and egg production and processing. A brief summary of the completed project is shown below. A complete report, along with information on other association research, may be obtained by going to the USPOULTRY website.

Viral genotyping can improve infectious bronchitis control

Infectious bronchitis virus continues to cause losses for broiler and layer operations around the globe in spite of extensive vaccination and diagnostic efforts. Dr. Richard Currie, veterinarian, molecular biologist, and co-founder of x-OvO, said that there are three types of diagnostic test for determining the infectious bronchitis status of a flock of chickens. He told the audiences of the WATTAgnet.com webinar, Infectious Bronchitis – Using PCR analysis to identify the predominant strain, sponsored by MSD Animal Health, that three diagnostic methods, ELISA, Hemagglutination inhibition, and molecular diagnostics (PCR), all have distinct advantages and disadvantages.
Currie explained that ELISA testing can be low cost, automated and convenient, but it doesn’t differentiate between different subtypes of the virus. Hemagglutination is low cost, serotype differentiation is possible and he said it can be more useful than ELISA for the construction of an appropriate vaccination program. Unfortunately, he said that the results of Hemagglutination inhibition are sometimes not clear, because there is no differentiation between vaccine response of the same serotype.
Genotyping the virus lets you differentiate vaccine strains from true field viruses so you know where your disease challenge is coming from, said Currie. He explained that vaccines from the same serotype of bronchitis virus can still be different genetically. So vaccines from different companies will be different genetically even though they are the same serotype. Currie said that using DNA sequencing is what lets you differentiate between different vaccine strains and field viruses
Currie’s three practical applications of infectious bronchitis molecular diagnostics:


1. Ensure your flocks are vaccinated
In a test of 300 flocks of commercial broilers in the EU, Currie reported that 18 percent were negative for Infectious bronchitis virus (which means they weren’t effectively vaccinated), 8 percent were sample untypeable (Usually meaning they were exposed to a field type Bronchitis virus that you can’t identify because there is so little genetic material).


2. Vaccinate against true field viruses
This method allows for clear differentiation of vaccine strains from field viruses.
When applied to field outbreaks, it can clarify the apparent large number of field viruses and allow their reclassification.


3. Optimize protection: determine what vaccination programs are associated with the fewest field viruses
Currie explained that current technology does not provide conclusive proof via sequencing analysis that a particular vaccine will protect against a certain field virus. However, molecular characteristics can be identified that are supportive of a protectotype response of a particular vaccine strain for an identified field strain.
To learn more about the field data Currie has gathered on the genotypes of infectious bronchitis virus found in broilers in layers in Europe and the Middle East view the archived webinar.

Molecular technology can identify IB strains

Advances in molecular technology now make it possible to pinpoint the strains of infectious bronchitis (IB) affecting poultry flocks and to tailor a vaccine program that can more effectively control the disease.  By comparing sequences of commercial infectious bronchitis (IB) vaccine strains to those in the field, it is possible to determine if an IB field strain is identical to a vaccine IB strain or different in a defined way.
Register at https://www1.gotomeeting.com/register/357574856?linknumber=website to attend “Using PCR analysis to identify the predominant IB strain,” a webinar sponsored by MSD Animal Health and presented by WATT Global Media. The webinar will broadcast on Tuesday, January 13, 2015, at 9 a.m.
By attending this webinar, you will learn:


• How PCR analysis (genetic analysis) helps identify variants
• How to identify the "vaccine strain"
• The persistency of 4/91
• Local/region IB variants
The speaker for this webinar will be Dr. Richard Currie, veterinarian and co-founder of x-OvO.
Currie is a veterinary graduate of Edinburgh University with a Ph.D. in cell and molecular biology. He began his poultry career with Aviagen as the veterinarian in charge of the pedigree program. Currie moved to Fort Dodge Animal Health as director of poultry, prior to co-founding x-OvO in 2007. x-OvO is a specialist diagnostics organization, marketing a complete line of serological tests, plus diagnostic antigens and sera.