Farmscape for October 26, 2021

Researchers with the Western College of Veterinary Medicine hope to identify the mechanisms of Brachyspira infection in an effort to develop vaccines to protect pigs from the bacteria.
The Western College of Veterinary Medicine, in partnership with the Natural Sciences and Engineering Research Council, is exploring the mechanisms of infection in hopes of developing vaccines to prevent disease associated with Brachyspira.
Dr. Matheus Costa, an Assistant Professor with the Western College of Veterinary Medicine and an adjunct professor with Utrecht University, says we don't fully understand how know how Brachyspira induces disease.

Clip-Dr. Matheus Costa-Western College of Veterinary Medicine:
We know that Brachyspira hyodysenteriae and hamsonii does not attach to the host.
Think about it as a free-living bacterium in the large intestine that never invades the host, never attaches directly to it but yet causes very severe disease, which is different from Brachyspira pilosicoli.
We know that Brachyspira pilosicoli will actually attach to the cells and we believe that's how it will induce disease.
So, one of the key challenges is characterising that.
How specifically, from a molecular perspective, is Brachyspira hyodysenteriae and hamsonii which cause swine dysentery, how do they actually cause disease?
We don't know if it's one toxin or multiple toxins.
We don't fully understand that.
We have definitely characterised a few toxins in that past decade or so here that could potentially contribute to that but we haven't been able to completely reproduce the disease just with these candidate toxins without the bacteria alive when exposing a suspectable pig.
We're missing that gap.

Dr. Costa says another gap is that we don't understand why pigs that have had the infection don't develop protective immunity.
He says we've learned Brachyspira shuts down one specific response cascade that activates and allows B cells to mature and produce antibodies and the hypothesis is that this prevents the pig from developing immunity.
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Bruce Cochrane.

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