Tails of Truth: The Truth about Veterinary Medicine

Rethinking Heartworm Prevention: A Fresh Take on Heartworm Protocols

• Dr. Angie Krause, DVM CVA CCRT • Episode 16

Share episode

✏️ Podcast Summary

In this episode of Tails of Truth, Dr. Angie breaks down everything you thought you knew about heartworm prevention and invites you to rethink the one-size-fits-all approach many clinics follow. She and JoJo explore common veterinary practices around annual testing, year-round prevention, and how geography, travel, and climate play a bigger role than most pet parents realize.

They also tackle the realities of holistic care: what it means to balance low-toxicity living with real disease prevention, why heartworm treatment is more dangerous than prevention, and how to empower pet parents with information — not pressure.

Plus, Dr. Angie shares a free resource to help you navigate parasite prevention with more confidence. Visit boulderholisticvet.com and use code TRUTHTAILS to access her Parasite Prevention course for free.

✅ Key Takeaways

  • Testing isn’t always necessary to dispense prevention. In low-risk areas, annual testing may not make sense.
  • Access to prevention should be simple. Withholding medication due to skipped testing can be counterproductive.
  • Prevention is safer than treatment. The heartworm treatment protocol is highly toxic; prevention is a micro-dose of ivermectin.
  • Seasonal prevention can be appropriate. In places like Boulder, Colorado, heartworm risk is seasonal due to mosquito activity.
  • Pet travel matters. If your pet leaves your local area, even briefly, prevention should be timed to cover that exposure window.
  • Heartworm affects cats, too. Though less common, cats can still get heartworm.
  • “Natural” doesn’t mean skipping prevention. A holistic approach still includes smart, low-risk prevention strategies.
  • Understanding transmission helps. Mosquitoes are the only vector — if they’re not present, the risk drops significantly.

🔊 Sound Bites

“Just give it to them. Like if you want to prevent this disease.” — Dr. Angie
“Just do it. Just do it. I don’t want it to be your dog.” — Dr. Angie
“Prevention is a holistic approach to heartworm.” — JoJo
“It’s one of the least toxic things we do — it’s just ivermectin.” — Dr. Angie
“We’re not saying don’t test. We’re saying don’t withhold care.” — Dr. Angie
 

Please subscribe and review! xoxo Dr. Angie & JoJo


Dr. Angie Krause (00:05.295)
Welcome back to Tails of Truth, where we tell the truth about veterinary medicine. I'm Dr. Angie, and this is my nurse, JoJo. And today, we're going to talk about heartworm disease. But first, JoJo and I haven't seen each other in what feels like weeks. We are in the middle of the summer, and we both have children. And we feel like we're long lost coworkers.

JoJo (00:22.67)
It's

Dr. Angie Krause (00:34.499)
Even though we probably communicate most every day, I haven't seen your face in weeks. I know they're just short texts and emails.

JoJo (00:34.702)
It's been a minute.

That's true. I actually heard your voice. In a week. So we are recording this early morning hours before the families rise with makeup on, which is not, that is not a daily for us. But we're here to talk to you about heartworm because that matters. It matters to us.

Dr. Angie Krause (00:50.937)
before the... Mm-hmm. Yeah, we got up early to hang out.

Dr. Angie Krause (01:00.101)
There's mascara. It really does. And we have some hot takes.

JoJo (01:07.948)
Yeah, you have, you have a, I've wanted to talk about this because you have a particular take that I've not heard in any other practice I've ever worked in.

Dr. Angie Krause (01:17.627)
I know, and I don't get it. And I have a little anxiety that some other veterinary professional is going to like school me with some information I don't have. But I don't think that's true. But should we just get right to the hot take? And then we'll talk about heartworm disease in general.

JoJo (01:30.285)
Mm-mm.

Yeah, let's get the big, let's just open it.

Dr. Angie Krause (01:37.083)
Let's just get to it. So if you have a dog or cat, because we can talk about cats and heartworm disease too, your veterinarian probably makes a really big deal about testing before they give you new prevention. we can give you prevention for a year. Most clinics require a new test every single year. And then there's even like,

You know what, wait for us to get this test back before you give any prevention. We'll call you or if we don't call you, you can give prevention, but wait X amount of time. And I don't understand this because when dogs turn positive, one of the ways we treat them is with the preventative medicine. And so I don't understand this obsession of not being able to dispense a new prescription without a heartworm test.

And it's not that I don't understand why we heartworm test because we need to make sure our prevention is working and we need to know that status, but it's not necessarily so we can give prevention. And that's the piece I don't understand. And it annoys me.

JoJo (02:46.563)
Mmm.

Yeah, so how do you navigate it differently?

Dr. Angie Krause (02:53.435)
Well, I don't require heartworm tests to dispense prevention. It's kind of like telling somebody, um, I don't know if I can find a good, um, analogy, but I always think of it as like dispensing contraceptives to teenagers. It's like, just give it to them. Like if you want to prevent this disease, heartworm disease.

JoJo (03:16.302)
Mm.

JoJo (03:21.228)
Yes.

Dr. Angie Krause (03:23.439)
then dispense the prevention easily. Make it easy. And I do think we should do testing. So when someone comes into my exam room and they're like, I'm not going to test, I still dispense the prevention because I really don't want that dog getting heartworm disease. Now I also live in a place, mean, Boulder County, in the 18 years I've been here, I've seen one

JoJo (03:43.606)
Mm-hmm.

Dr. Angie Krause (03:50.469)
heartworm positive dog that I swear got it traveling somewhere else.

JoJo (03:54.412)
was just gonna say that dog probably was not born and stayed in this region. Yeah.

Dr. Angie Krause (03:57.04)
Yeah.

Exactly. So I don't see a lot of heartworm positive cases. And so maybe a veterinarian practicing in Mississippi is going to listen to this and be like, my gosh, what is her problem? But I just don't understand how rigid we get about it. Because there are some moments that I would like to use that money for something else if someone's financially restricted.

and I can either do a vaccine that I want to do or something else that I want to do or, you know, do blood work or something else that feels more important than that heartworm test, the hang up on the heartworm test or the other thing. If I have a really scared, maybe sometimes fear aggressive dog, I might not choose to have a blood draw be the battle of the day.

JoJo (04:54.24)
Mm-hmm

Dr. Angie Krause (04:55.739)
So anyways, but I will still dispense heartworm prevention because I want that dog to be protected.

JoJo (04:57.238)
Yeah.

JoJo (05:01.144)
Well, it makes so much logical sense to tack on a heartworm test if you're already doing blood work. Just, mean, it's financially pretty insignificant to add that on, but to do one solo for the purpose, yeah, for the purpose of dispensing heartworm. That feels different.

Dr. Angie Krause (05:06.703)
Yes.

Dr. Angie Krause (05:12.005)
Yes.

Dr. Angie Krause (05:19.109)
Yeah. Yeah. So that's, don't understand it. It's universal. It's every clinic. And I really do want to know my patient's heartworm status. I want to know it for so many reasons, for their cardiovascular health, before anesthesia. It's not that I think heartworm testing is silly. I just don't understand the correlation. And people get irritated with us when we won't dispense without a heartworm test. And so.

That's why I love working at Boulder's Natural Animal is because I can be reasonable in case by case. Like some people are like, why do I need to do a heartworm test when I get, give my dog prevention year round, which we should talk about seasonal versus year round prevention.

JoJo (05:54.958)
Hmm.

JoJo (06:03.648)
Mm-hmm.

Yep, was gonna say that's another hot topic that you walk around with.

Dr. Angie Krause (06:09.903)
Yes, yes. And so I, when people push back, I just don't have a good reason to make them do it. And so I will be like, well, let's do it every other year. So for people that are on giving their dog prevention all year round in Colorado, in Boulder County, I just want to be really specific about that. Because if you live in Florida, like none of this applies to you.

I am totally fine testing every other year because I think what they're saying is reasonable. You're like, why would I? Where's my prize for doing year round prevention in a place with a, with a complete winter season.

JoJo (06:44.565)
Mm-hmm.

JoJo (06:50.19)
Well, and in veterinary medicine, I think we've done a good job of getting that message to the people because the average customer comes in or the average pet parent comes in knowing they need their heartworm test. It's something that we have trained pet people to know it's needed. And so I think sometimes when they have moved to Colorado or they're living in Colorado and they meet you, it's just...

Dr. Angie Krause (07:10.223)
Yes.

JoJo (07:20.664)
There's a whole educational unlearning that has to take place for them to understand why they don't have to have the heartworm tests. So maybe start there. What would, if somebody came in and they've done prevention.

Dr. Angie Krause (07:24.559)
Yes.

Dr. Angie Krause (07:37.159)
Well

Okay, so there are a few, well, okay, first of all, we'll get to the point here, but in Colorado, like if you're in Boulder, Colorado, your dog can't get heartworm disease when there are no mosquitoes. And our mosquito season is roughly June to September. Every once in a while in May, we might have a warm month, but for the most part, it's June through September, and sometimes we even have snow at the beginning of September.

So sometimes it's even less than that. And so if there are no mosquitoes, your dog or cat cannot get heartworm disease. They just, that's how it's transmitted. They can't get it otherwise. A lot of veterinarians here will push for year round prevention. And the reason why they do that is if you travel with your pet and forget about it, like if you're like, I'm going to make a quick trip down to Texas, Oklahoma, wherever, go, you know, travel up and down the West coast.

then that's problematic because people forget about it. So veterinarians here are like, I just want it on the first of every month, no matter what. And that makes sense to me. But it's a good habit. And I work for a lot of people that probably could use that habit because they have so many things going on in their life. And we even had, remember the dog in our practice, that became heartworm positive because they traveled. And so I think

JoJo (08:47.918)
That's a good habit.

Dr. Angie Krause (09:09.153)
I understand that. The other reason is that heartworm prevention also protects from pair, intestinal parasites, which can be transmitted to people, certain, certain intestinal parasites. So a lot of veterinarians feel like if there's kids in the house, I just want to make sure we're covered. I think that's a little excessive. As we experience global warming, we do see more intestinal parasites in this area.

but still not in the winter and not as much as you would think. so veterinarians have a good reason for doing that, but I do think it's a little excessive, which is.

JoJo (09:41.678)
Mm-hmm.

JoJo (09:47.758)
Well, I mean, I will own that I I only heart guard, I only prevent in the summer months. That's all I do. I just have it on my phone to remind me. it's time to start.

Dr. Angie Krause (09:53.519)
Mm-hmm.

Yes.

Dr. Angie Krause (10:02.137)
Yeah, well.

JoJo (10:03.062)
And then I just base it on, how's our weather changing? But I actually haven't seen a mosquito this year, which surprised, I haven't. Yeah, I know, but I'm still, I'm still preventing.

Dr. Angie Krause (10:09.433)
You haven't. Nice. Nice.

Yes. Well, I think that that is totally fine. And a few years ago, so when I had my pug, I hardly ever did heartworm prevention because I just don't think the odds of getting a heartworm disease in Boulder County are high enough to matter. Now, what I'm telling my clients is that I think it's possible that could change because we are warming up and because we're seeing different parasites and the

flora and fauna are changing and the types of mosquitoes that we could have here are going to be different and maybe they can live longer. So as I understand right now, not only do we not have in Boulder County specifically, and I'm only going to talk about Boulder County because the minute you go down an elevation, everything changes. And I mean, I think difference, if Pueblo, Colorado could have a completely different fauna than we have here.

JoJo (11:05.74)
Mm-hmm.

Dr. Angie Krause (11:14.755)
So we don't have the correct mosquito to transmit heartworm disease. And I don't know if this is true or not, but this is a personal theory. I don't think the mosquitoes live long enough to bite an infected dog, have the heartworm larva mature, and then be able to bite another dog and infect them. And so I think

JoJo (11:38.252)
Yeah, talk about that. Talk about the life cycle so that people understand how this, what the life cycle of the heart worm is.

Dr. Angie Krause (11:44.557)
Okay, first of all, I have to get the cat on my lap because he's going to scratch me. Hold on. Come here, Fritz.

JoJo (11:49.133)
Okay.

JoJo (11:52.654)
Well here, I'll keep talking while you do that. Well, cause I also have this theory of, and maybe this is not true either. This is just made up in my own head. But I wonder if we will see a heavier load of heartworm positive dogs as kennels and breeders or the, guess it's the, like humane societies are moving dogs from areas. So.

Dr. Angie Krause (11:54.107)
Okay, okay, he's good.

JoJo (12:19.552)
as we get Texas dogs and New Mexico dogs here for adoption, do we increase the risk of, well, the mosquito, guess, yeah, I'm like the mosquito still has to be with it. That's, yeah, no.

Dr. Angie Krause (12:28.045)
Yeah, don't think we do. And that's what veterinarians always tell clients, like, we have all these heartworm positive dogs coming in from other states, but I don't think, I mean, we have had that for decades, decades. And so if the...

JoJo (12:35.213)
Yeah.

JoJo (12:40.8)
Yeah. So we actually need the mosquito is the key component to this here. It's not the positive dogs.

Dr. Angie Krause (12:45.72)
Yeah, the-

It's not the positive dogs. And if someone wants to tell me how wrong I am, please do that. I mean, I have, you know, I've been here for 18 years and I have had one heartworm positive dog. I mean, and I do heartworm tests all day long. That's probably number one test. And so it's like, we still do it. And the reason why we do tests, so if you live in another state, my gosh, all the cats are coming. If we,

JoJo (12:58.51)
Mm-hmm.

JoJo (13:05.304)
Mm-hmm.

Dr. Angie Krause (13:15.745)
If you live in another state, the reason why we test is because heartworm prevention can fail. so veterinarians are not just trying to make money. We're really trying to make sure that one did the prevention fail. And it's really important to know the heartworm status of your dog. And so in no way do I think heartworm tests aren't important. I just think it's strange that we are, I've got a tail right in my face. I just think it's strange that we're withholding prevention.

based off of a heartworm test.

JoJo (13:48.332)
Yeah, I think that's fair.

Dr. Angie Krause (13:51.375)
And I just want to say one more thing. If you're trying to be integrative, natural, less chemicals, preventing heartworm disease is like the one of the least toxic things that you can do because it's just ivermectin. It's this micro dose of ivermectin and it's in and out of your dog's system in like 48 hours. It's not there for long. I don't worry about it.

But if your dog gets heartworm disease, the treatment for that is so toxic. It is an arsenic derivative. And while I still support doing it, your dog does not need to have heartworm disease. It's so much easier to prevent it. So for those of you that are worried about toxic prevention, preventing heartworm disease is just not one of those.

JoJo (14:25.538)
Mm-hmm.

JoJo (14:44.53)
Right, your risk of toxicity is much lower on doing annual or monthly preventative. Yeah.

Dr. Angie Krause (14:52.601)
It's like zero. is, ivermectin is one of the most studied, safest drugs, and you're not even using like a therapeutic dose. It's like a micro whisper dose. It's so small that dogs like collies that have a gene that makes them sensitive to ivermectin can still take it. That's how small it is. So.

JoJo (15:16.398)
Okay, I was gonna ask actually specifically about that. is a phrase and I can never remember it about, oh, maybe that's with tick and flea. Yeah, that's the one. Okay, I can never remember it for some reason. It should stick, right? It's meant to stick. It doesn't stick. White feet don't treat with ivermectin specifically.

Dr. Angie Krause (15:24.441)
White feet don't treat. yes.

Dr. Angie Krause (15:34.969)
Yeah, I mean, there was a time, I think it was in the maybe 90s, early 2000s, where we were like testing for this gene mutation. And now we know we don't have to do that. We can if we need to treat for other things, but we don't have to do that for prevention.

JoJo (15:52.846)
Okay, good to know.

Dr. Angie Krause (15:53.669)
So small. Yes. OK, what else? What else did we say we would talk about? We never really prepare for these. This is all unscripted.

JoJo (15:57.515)
Okay.

JoJo (16:02.83)
Well, think, okay, so something else I've heard you say is for people who are not doing prevention, because we do have people who really are trying to be minimal. And this is an area that we can kind of move that bar without too much risk in Boulder County, again, but they do travel. So when they're traveling, the medication or the preventative reaches backwards, right? And not forward.

Dr. Angie Krause (16:19.471)
Yes. Yes.

Dr. Angie Krause (16:28.599)
Yes. my gosh. That's so important. Yes. Okay. So what, when you're giving the heart guard, ivermectin, whatever product you're using, it's reaching back the last 30 days. So it's killing any like baby infection that's there. So that's how heartworm prevention works. And so if you travel, don't just give it before you travel, go travel, and then think you're good for the next month. it reaches back. And so if you've traveled,

JoJo (16:31.36)
So talk about that.

Dr. Angie Krause (16:58.223)
then do it after you travel, depending on how long you travel. If you're traveling for months, just keep doing it throughout, but don't stop until you've reached that travel with the 30 day reach back. Does that make sense? Did I say that in a way that makes sense?

JoJo (17:13.708)
Well, I understand it, so I'm not a fair person to ask. I hope people can say that was confusing. What I heard is if you're traveling for 30 days or less, and you had not given preventative before you left, give it when you get back, because it can reach back 30 days. But ideally, you give it before and after enduring.

Dr. Angie Krause (17:16.347)
Okay. Yeah.

Dr. Angie Krause (17:26.938)
Yeah.

Dr. Angie Krause (17:31.579)
That's right.

Dr. Angie Krause (17:37.593)
Yeah, mean, depending on what you're doing.

JoJo (17:40.792)
but the before is only gonna reach back 30 days. So if you give it before your trip, you're actually just treating anything that your dog was exposed to before you left for your trip. And then if you're giving it while you're on the trip, you're just constantly going back 30 days. I maybe just made it all the more confusing.

Dr. Angie Krause (17:48.324)
Yeah.

Dr. Angie Krause (17:54.041)
Yes. So I know. So yeah, just keep giving it until you've reached back 30 days enough to travel your, to cover your travel. Yeah.

JoJo (18:04.204)
Yeah. Okay, well, here's another question. We don't really talk about heartwarming cats.

Dr. Angie Krause (18:09.539)
We don't because they're more resistant. and so we think they get it less, but they do get it. So here in Boulder County, we had a barn cat, that sadly passed away and I did a necropsy or an autopsy. And then I sent the heart in and they were, they were convinced this cat probably had heartworm disease, but I don't know where the cat came from.

And so I don't know if that cat picked up heartworm disease in Boulder County. They didn't find any adult worms, but they suspected. So I don't know. It's possible that the cat didn't have heartworm disease and the pathologist was wrong because sometimes we're just wrong. but cats can get it. They tend to clear it on their own, but it can be fatal for kitties too. I have to admit that I have never given any cat of mine heartworm prevention.

I definitely won't be giving my indoor cats heartworm prevention, not because I don't think it's safe, but just because I would not choose to spend the money on preventing it in Boulder County. But if you have an outdoor kitty in Florida, I think it's worth doing. Cause once again, it's just ivermectin. Just do it.

JoJo (19:23.648)
Mm-hmm.

JoJo (19:27.827)
Right. But there are different preventatives than ivermectin. that is that correct?

Dr. Angie Krause (19:33.687)
Yeah, I mean, you can use other things like Moxodectin, but yes. But I think for...

JoJo (19:40.342)
Because some of the multi that are doing not just heartworm prevention, but they're also doing external parasite preventions, they use a different formulation.

Dr. Angie Krause (19:43.727)
Yeah.

Dr. Angie Krause (19:48.667)
Flee and tick. Yes.

Dr. Angie Krause (19:55.587)
Right. So they would use, mean, I think most of those have something like Moxie dectin in there for the heartworm prevention piece. And I'll say it again at the end, but if you want to learn more about how I manage flea and tick prevention as naturally as possible, I have a course that you can get for free if you listen to this podcast. And so if you go to boulderholisticvet.com and you go to the courses,

JoJo (20:00.77)
Mm-hmm.

Dr. Angie Krause (20:23.193)
and it's called, what do we call it? Parasite prevention in dogs and cats? I think it was like the...

JoJo (20:26.048)
Yeah, it has a really long name, a holistic approach to the creepy crawlers. But on the main page, it'll say, flea and tick prevention to simplify what people are looking for. Yeah.

Dr. Angie Krause (20:30.454)
Okay

Dr. Angie Krause (20:36.503)
Yes. And if you use the code truth tales, T-A-L-E-S.

JoJo (20:44.106)
O-T-A-I-L-S.

Dr. Angie Krause (20:46.781)
I thought you made it both. T-

JoJo (20:48.874)
I think I do. put it in there both just in case. In case somebody spelled it wrong.

Dr. Angie Krause (20:51.607)
Yes. T-A-I-L-S or T-A-L-E-S. So just type in truth tales, however you want to spell tails. And then you can get it for free. then, cause that's a whole, that's a whole conversation about if once we get into ticks and fleas which we should do, we'll do an episode on that at some point.

JoJo (20:58.317)
Yes.

JoJo (21:08.8)
Mm-hmm, it really is.

JoJo (21:16.332)
Yeah. So heartworm. Okay. I don't, are there more things you want to talk about around? We didn't do the life cycle. Okay.

Dr. Angie Krause (21:22.571)
Hmm. Let's see. Okay. We've talked. That's okay. That's science. You can get on the American Association of heartworm. Wait, what's it called? American Heartworm Association. I was like, I'll just get those words together somehow. And then you can look at the life cycle of the mosquito. But here, the other thing I really want to say is, even if you live in Boulder County in the summer, I'm really recommending prevention.

I'm really nervous about the dogs, especially that are my patients, that are going to turn up heartworm positive. And those are going to be the dogs that make us realize that we do have it here and they can get it here. And I feel very protective of my patients. And so just, just do it. Just do it. Just do it. I don't want it to be your dog.

JoJo (22:10.2)
Hmm.

JoJo (22:16.662)
Yeah, and I would say because once they are heartworm positive, there's not much holistically that we can do. And it's not a fun process for the dog or for you. It's just not just from the medication standpoint, but from the non exercise induced, you know, just, I don't know, kenneling them. Yeah. And actually asking active dogs that want to be active still, but

Dr. Angie Krause (22:23.982)
No.

No. It's pretty awful. Yeah.

Dr. Angie Krause (22:38.095)
All the crate. Yes.

Dr. Angie Krause (22:45.519)
Yeah.

JoJo (22:46.412)
because it's a heavy load on their heart, it really is.

Dr. Angie Krause (22:49.997)
Yeah. So just prevent it. And I know, like, even if you're so holistic and natural, I get that. And let's keep doing that. Let's be natural. You can feed all the things that you want to feed and do all those things, but like, just prevent it. I'm nervous. I used to not care about heartworm prevention. I didn't care at all. But now I'm like, just in the summer, just a few months out of the year, let's do a little ivermectin. It is the thing.

JoJo (23:11.438)
Yeah, that is the holistic approach right there. Prevention is a holistic approach to heartworm. That is what you're recommending. So, yeah.

Dr. Angie Krause (23:19.179)
It is, just do it. Okay, I think that's it. Go grab that course, because we do talk about heartworm prevention in that course. Use Truth Tales, you can get it for free. Okay, we want to hear from you, so leave a comment wherever you're listening to this. Have we decided that people can leave comments anywhere?

JoJo (23:32.472)
Great. Yeah. Wonderful.

JoJo (23:43.554)
Well, I know on Spotify there are comments, YouTube there are comments. You are supposed to be able to leave comments on Apple and I just haven't. Okay, I'm working on the SEO stuff. And learning how to upload and all the non-nursy things that I'm doing. Nurse slash tech. Yeah, so if you learn how to put a comment, would love to hear it.

Dr. Angie Krause (23:45.78)
huh.

Yeah.

Dr. Angie Krause (23:56.251)
Yeah, I know we're...

Dr. Angie Krause (24:02.669)
I know we're just veterinary professionals podcasting with no help. We're just doing this by ourselves.

Dr. Angie Krause (24:12.581)
Yeah, then send us an email saying, hey, I put a comment, or maybe that'll notify us. We don't know.

JoJo (24:15.886)
Yeah, maybe they exist and I haven't found them. So I'm so sorry if I have not responded.

Dr. Angie Krause (24:20.795)
Okay, we will see you next time. Bye.

JoJo (24:24.877)
Bye.