EAHO #29 - PART 2: "Theileria deep dive "with Dr. Craig Payne of The University of Missouri Extension

For the modern large-animal veterinarian and producer alike, the Theileria protozoan and related disease Theileriosis demand understanding.

In this episode (Part 2 of 2), Dr. Craig Payne, Extension Professor at The University of Missouri, finishes this critical two-part podcast on the details of Theileria/Theileriosis and its growing impact on the American cattle environment.

Part two covers:

• Involving veterinarians to make an individual "Theileria plan"
• Theileria/Theileriosis can LOOK like BRD (Bovine Respiratory Disease) - but know the difference!
• Minding the impact of Theileria/Theileriosis on new animals into a herd or system

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SPEAKER_00 0:05

Welcome to Every Animal Has an Owner. Large Animal Podcast for veterinarians and the people that depend on them.

SPEAKER_01 0:17

So I just had a question. So what should or what do you recommend a veterinarian do if or when a producer calls on a panic about, you know, what's Tyleria? And I think my word has it.

SPEAKER_02 0:27

So I think one thing that we got to keep in mind when we're talking about whether cattle are having a clinical disease event associated with Tyleria or not, is that a PCR test, which is a blood test that would need to be ran by a diagnostic lab, positive test alone probably is not sufficient in an animal to determine whether or not Tyleria was the cause of that disease or not. The reason why I say that is because we can have animals that are chronic carriers that may be ill because of another disease, but because they are chronic carriers, they will show up PCR positive for Tyleria on a test. And so as a veterinarian tries to make the determination of whether Tyleria is the cause of a disease problem, it's not only based upon the test, but it's also based upon their clinical findings. So is that animal anemic? Have they ruled out other potential diseases? Because one thing that we have seen in Missouri, because Tyleria is kind of the popular topic right now, is that people are still missing anaplasmosis as the cause of an animal that's having disease because they're so focused on Tyleria. Maybe the other important thing to point out here, we haven't done enough surveillance of cattle populations in Missouri yet to establish this. But when you talk with our colleagues in Virginia, when Tilaria passes through a cattle population, or let's take a cow calf herd, for example, it's not uncommon to find 90% to 100% of those cattle within that herd positive on a PCR test to Tyleria. Again, that kind of goes to the question of what does a PCR test mean if you've got an animal showing some clinical disease. If you've got 100% of a population that's positive and they're all just chronic carriers, there very well could be something else going on just besides Tilaria.

SPEAKER_01 2:58

Dr. Payne, what are your thoughts about cold morbidities associated with tilaria?

SPEAKER_02 3:03

What I'm hearing quite a bit of is coming from situations where feeder cattle are showing symptoms that are reminiscent of ovine respiratory disease, but these cattle are either non-responsive to treatment with antimicrobials, or instead these animals are dying, there's necropies being done, and veterinarians are not finding any lung pathology, but they are finding on a test that these animals are PCR positive to Tyleria. So that has brought up this conversation or discussion within the veterinary profession as to you know, if we have Tyleria and we have an animal that's at risk for respiratory disease because of shipping, um, commingling, whatever the case may be, does tiluria contribute to that severity of that BRD? Or is because thyria can through anemia look very similar to BRD, is itself the primary cause of some of these issues. Nobody really knows yet. Uh there's lots of work yet to be done.

SPEAKER_01 4:27

Is there any way for producers to keep Tyleria out of their herds? I mean, is this Is it a lost cause? It's moving. Yeah. Is it a lost cause or is it you know it's just a matter of time?

SPEAKER_02 4:38

So uh there probably one of the most difficult conversations I have with producers is whether or not Tyleria, if you can keep Tyleria out of a cow calf herd, for example, or not. And and so I I it really depends upon that particular circumstances that that operation is in. Let me qualify that by saying, you know, if that cattle operation is in a in a location where chileria is pretty much endemic, and there's quite a few cattle in that area that are already infected with Tyleria. And if there is also an established Asian longhorn tick, I think the likelihood of a operation being able to keep it out in the long term is probably not sustainable. Not saying it's impossible, but the odds are not in your favor. You know, that does not mean that a person should just throw their hands up and walk away. Um, what I've been discussing with our producers in Missouri as Tyleria has passed through our state is in relation to how do we minimize transmission in an operation if that disease or protozoa gets into the system, so that when animals are exposed to that protozoa, it's at a low level, which gives them more likelihood to be able to deal with it. And so in those situations, to minimize the exposure level, it basically boils down to controlling ways in which this disease is transmitting, controlling Asian longhorn tick populations, fly populations, you know, maybe changing needles, cleaning blood-contaminated equipment between each animal use, so on and so forth. And so for the cow-calf operation, however, that is in a place where um chilerea is not common, andor Asian longhorn tick populations are not established, keeping it out of a herd becomes a bit easier, but still yet, they're gonna have to be mindful of the status of the animals that they're bringing into that system. And so, regardless of what situation you find yourself in, uh, you know, uh again, it's gonna be extremely important for people depending upon their goals to work with their local veterinarian and come up with the way they're gonna manage this.