PCVAD and the Kansas Experience
January 2, 2008 —
A presentation addressing PCV2 research has been uploaded and is available for viewing on the Kansas State 2007 Swine Day website.
The PowerPoint presentation entitled "Circovirus Disease in Kansas - What a Difference a Year can Make!" from Kansas State's 2007 Swine Day symposium describes the outbreak of PCVAD in Kansas during late 2005 and the subsequent clinical and research investigation that followed. The presentation does an excellent job describing the impact of the disease and the subsequent experience with vaccination. It discusses such topics as:
- Vaccines - how do they work, differences?
- Growth - what is the impact in immunized animals?
- Immunity - how can we use antibody to guide best vaccine use?
- Genetics - is there a difference between genetic lines in response to vaccine?
- Diagnostic methods - next generation methods from the Kansas State VDL
- PCV2 itself - is it changing and what does that mean?
- New tools - tests needed to differentiate strains in infections, vaccinated successfully vs. failed to immunize
- Virus elimination - is it possible?
The presentation describes vaccine field trials showing significant declines in mortality and improvements in growth performance resulting in an economic benefit of $8.68 per pig in one study. Some additional findings regarding vaccination and immunity include:
- Full doses are absolutely recommended if possible
- Demonstrated antibody response is better
- Clinically fewer lightweight pigs
- Clinically fewer affected pigs than half dose
- Maternal passive immunity inhibits antibody response to vaccine
- The younger the pig, higher the passive antibody and less likely to effectively immunize?
- But must immunize before infected/viremic
- Impact on performance trials to be done
- Two doses appear to produce a superior response over single dose
- IFA has high correlation with SN
- Question of passive interference with immunization is not answered conclusively
- Variation herd-to-herd and group-to-group
- Why do some groups/pigs apparently fail?
- Timing vaccinations, repeated doses?
- New antibody tests being developed
- Quantitative DIVA, differential ELISA
- Essential for compliance, apparent failure and herd status/timing decisions.
[Thanks to Drs. Steve Henry and Lisa Tokach for forwarding this information.]
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