Researchers with the Western College of Veterinary Medicine have identified the TlyA protein as one factor playing a role in the severity of Brachyspira associated diarrhea in swine. 
Brachyspira is a common bacteria found in several species, certain strains of which can cause symptoms in pigs ranging from mild diarrhea to severe mucosal hemorrhagic dysentery. 
Researchers are exploring the role of certain proteins that are part of Brachyspira hampsonii. 
Dr. Matt Loewen, an associate professor said the environment could cause some variability in symptoms such as the barn the diet. Still, other differences are due to species differences. 
With the species differences there are specific proteins expressed in one species of bacteria but not in another species of bacteria. So there are specific proteins expressed in more virulence and then they’re not necessarily described in less virulence. 
“We’ve specifically narrowed down different proteins that could be important virulence factors to a couple of proteins involved in hemolysis. There is one protein we’re spending a lot of time looking at is TlyA, which looks like it could be a hemolysin.” 
But looking at other less pathogenic Brachyspira species, they have mutations in them that would potentially disrupt its function.  
“We’ve made those mutations and demonstrated that the protein does not function as a hemolysin and missing a few other functions if those mutations are there.” 
Dr. Loewen said this leads to the belief that this protein is central to how severe an outbreak of Brachyspira is associated with diarrhea. 
“I think at this point it’s pretty much baby steps in understanding the disease. We still have a lot more to do. We need a comprehensive understanding of how the disease works to combat it.” 
The disease has been around for almost 100 years but is still dealing with it, so this is one small piece of the pie. The key is to know all of this disease’s on and off switches. It would appear that TlyA is one of the on switches so right now they’re trying to figure out that one. This will assist breeding programs to develop pigs that potentially would be less susceptible to Brachyspira. 
He makes the point while a very simplistic look at things there are lots of issues with doing that but that’s a general idea. 
“The other thing is that, we now know that this TlyA is an important factor in the virulence of these bacteria. So I think as new strains appear it will help us with the understanding of, is this a virulent strain, is this something else, knowing that this protein and a certain sequence of this protein are important for the virulence and severity of the disease.””
Dr. Loewen said the focus is on understanding where and how TlyA interacts with the animal. •
— By Harry Siemens