Blister Beetles

Chris) Hello and welcome to Horsin’ Around. I’m Dr. Chris Blevins here at Kansas State University Veterinary Health Center, today joined by Dr. Laurie Beard. She is a Clinical Professor here at the Vet School and a specialist in Internal Medicine here in the Equine Section. So today we’re going to talk about a topic that a lot of people, especially in the Midwest need to make sure they know about, and that’s Blister Beetles. Could you give us just a…I guess why should owners be concerned if they have horses with Blister Beetles? (Laurie) Yes, so Blister Beetles are an insect that tend to swarm in legumes and one of those legumes is alfalfa. And that occurs in Kansas and Oklahoma and other places in the Midwest. And Blister Beetles are extremely toxic to horses. And so hay can get contaminated with Blister Beetles, horses ingest any part of the beetle, they can develop very serious clinical signs that can result in death in some instances. (Chris) Now some of the aspects and what I’ve heard some owners say is, does the beetle have to be alive or really fresh, or if it’s dried out is it a lot better? Because you know, if they cut the alfalfa and maybe they’re just partially dried is that any better? (Laurie) No, unfortunately, in these cases it’s a dried out beetle. So, the beetles are actually killed when the hay is baled and so it doesn’t lessen the toxicity even when the hay is stored. (Chris) And I think that’s something that’s very important for a lot of owners to just remember is that it doesn’t take very much of that to cause issues on the horse. Now when you look at horses too, what are some signs so Blister Beetles I guess is maybe what the name is, but what’s the toxin that’s in ’em and why is it such an issue with the horse when they ingest it? (Laurie) The toxin in the Blister Beetles is actually called cantharidin and anything that toxin touches, mucus membranes, it’s actually…so it goes through the GI tract, it’s actually eliminated though the kidney. It can cause severe irritation, necrosis, anything it touches. And some of the clinical signs that you might see can vary. It might start out just the horse is not eating, maybe see some colic, but the most classic sign that we see is something called thumbs or synchronous diaphragmatic flutter. And that’s when the diaphragm is contracting with the heart. And so that’s very typical of Blister Beetle and that’s because the Blister Beetle or the cantharidin also causes low calcium in the blood as well. (Chris) Wow, that’s very interesting and things that I think owners need to be aware of, the other thing is just alfalfa and we feed horses alfalfa, is there anything that they can do to maybe hopefully prevent, if they’re gonna feed alfalfa, things to watch for, or things they can do to try to prevent with the alfalfa based on cuttings or anything like that? (Laurie) Yea, so we know that the Blister Beetles tend to swarm, usually it’s June/July. That’s the time where they’re most active. So we talk about the first cutting of alfalfa to be the safest. The other thing is paying attention or maybe asking some questions how the hay was baled? Not using crimpers would be one of those ideal situations. So, first cutting is the best, after that later cuttings would be the next step. But the cuttings that are happening in June, July are the ones that are most at risk for sure. (Chris) And I think even the regions too, you go further south, you’re more likely to see the Blister Beetles and more of the different cuttings. And then of course you go into Nebraska or the Dakotas, you hardly ever hear about it. (Laurie) Correct. So knowing where that hay comes from is really important. (Chris) Yea, and what should an owner do if they’re worried about that of the Blister Beetles, call a veterinarian, or call us or what do you suggest? (Laurie) So, if they see signs that they think they might have Blister Beetles, is call your veterinarian. And the other thing is to making sure that maybe the veterinarian needs to get keyed in, hey I’m feeding alfalfa, what do you think the chances of that can be Blister Beetle. And this is where actually there is a test for cantharidin, or Blister Beetle. It’s actually collecting urine really early in a disease process, large volumes. So that might be something even an owner could do. And that could be sent off to test to find out is there cantharidin in it or not, because if it’s got Blister Beetle cantharidin in it, then that hay can’t be fed. (Chris) And so when they would test or grab a sample, they could just get a cup and grab a sample? (Laurie) A cup. But usually we’re talking like half liter So, large… (Chris) Large cup. (Laurie) Three hundred mills…half liter, large cup, multiple cups. But again, early in those disease processes. (Chris) Good. And what would a veterinarian have to do or potentially would do if they’re worried about it in the earlier stages of Blister Beetle? (Laurie) So, what the veterinarian is going to do is when that horse needs to get treated, so usually these horses can get very dehydrated. They usually have very low calciums, other electrolyte abnormalities. So, usually it’s large volumes of fluids, lots of calcium. The stomach can get severely ulcerated, so we do something there. Other supportive treatments. But usually the hallmark is fluids and calcium supplements. (Chris) Great. Well thank you Dr. Beard on the information on Blister Beetles and I think it’s something that a lot of owners need to remember whenever they’re feeding alfalfa, especially around here in the Midwest. (Laurie) Yes, for sure. (Chris) Well, I’m Dr. Chris Blevins with Horsin’ Around and we’ll see you around.

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