Brachyspira hyodysenteriae, the organism that causes swine dysentery, had been thought to have been eradicated thirty years ago.

Researchers with the University of Saskatchewan in partnership with the Canadian Swine Health Board are working to characterize and control an infection that appeared in late 2009, causing similar symptoms.

Dr Joe Rubin, a doctor of veterinary medicine with the University of Saskatchewan, says we now know Brachyspira 30446 is a new species distinct from other species of Brachyspira and it does cause infection.

Dr Joe Rubin-University of Saskatchewan

What we don't know, particularly with our new strain, that Brachyspira 30446, is what the infectious dose is and the reason for that is we don't know how many organisms it takes to actually make a pig sick.

This varies quite widely among different pathogens so, for example, if we had five individual brachyspira in the environment, would that be enough to make a pig sick or would we need hundreds of thousands or millions of them.

We need to have a better understanding of what level of exposure leads to disease.

We also don't understand how it's getting into the barns so whether we have carrier pigs that are shedding these organisms without becoming sick and leading to infection of more susceptible animals.

We also don't know if there's transmission between pigs and wildlife.

We found a number of different kinds of brachyspira in wild birds but we don't know if those birds have acquired that brachyspira from pigs or if the birds are giving it to the pigs or if it's purely coincidental so it may be that birds and pigs independently of each other just happen to have brachyspira and there's really no implications for either species.

There's a lot of questions yet to be addressed.

Dr Rubin says the most important achievement so far is the ability to identify whether Brachyspira 30446 is the cause of an outbreak of swine dysentery and the ultimate goal is to come up with new strategies to control these organisms and their spread so we can prevent infection in the first place.