Farmscape for November 4, 2020

A new vaccine being developed by the Vaccine and Infectious Disease Organization will allow pork producers to differentiate between animals infected by Lawsonia intracellularis from those that have been vaccinated against the infection.
Lawsonia intracellularis, a bacteria found in most of the world's swine herds, causes Ileitis, a swelling of the intestine in pigs.
Researchers with VIDO-InterVac are developing a subunit DIVA vaccine which will allow producers to differentiate between infected and vaccinated animals.
Dr. Heather Wilson, a research scientist with VIDO-InterVac, says this is one of the most economically significant production diseases.

Clip-Dr. Heather Wilson-VIDO-InterVac:
It's an interesting disease because it's actually in about 95 percent of the herds worldwide so it's absolutely everywhere.
For the most part we almost call it a commensal, so it's just kind of in the background but it doesn’t cause disease and yet, in some instances and we don't understand why, it can actually lead to this disease.
Whether there's new strains coming in, that's something we're looking at.
There's two forms of the disease.
One form affects the weaner piglet, so just after you take them from mom.
If the disease attacks them at that stage, the piglets are usually fine.
They clinically don't show much sign of infection but the intestine gets thicker and they have a poor ability to absorb nutrients, which means you're feeding them more to get them up to market weight so it's more an economic impact.
But, if you impact the grower pig, that can be a devastating disease, bloody diarrhea and they have very poor health very very quickly.

Dr. Wilson says, by taking select proteins from Lawsonia, paring them with proteins that are not related to Lawsonia and administering both in a vaccine, the antibody response against the Lawsonia and the non-Lawsonia components can be measured and if they're both high you know the animal has been vaccinated.
And, she says, there is absolutely no way a pig can contract a disease from a subunit vaccine.
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Bruce Cochrane.

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