The Dog Liberator™

The Dog Liberator rescues abandoned dogs throughout the Southeast. Based in Central Florida, this non-profit organization fosters all of their dogs in a home environment. Founded in 2009, all dogs are fully vetted, spayed or neutered prior to adoption. The Dog Liberator focuses in rescuing the herding breed, which consists of Border Collies, Shepherds, Sheepdogs, Aussies, Collies, and Deaf/Blind Dogs.

Everything You Wanted to Know about Heartworm Disease

Everything You Wanted to Know about Heartworm Disease

Recognizing that their is no consensus in the medical community regarding heartworm treatment, we chose to treat our dogs under our care with slow-kill/ivermectin, however, after adoption, it is up to you to discuss the options with you vets, and choose the option that works for you.

Rolling up my sleeves and getting this over with. Nothing has confused me more than trying to explain the treatment of heartworm disease. It’s probably the most controversial topic I’ve come across. I’ve spent hours talking to vet techs, vets, homeopathic vets, other rescues, dog owners, and shelter directors. But, the vote is in, treating with Doxy, and ivermectin is the preferred method. What’s ironic, is it’s the only affordable method. Border Collie and Aussie owners beware, the dosage is different for certain breeds.

At this time, the vet of choice for treating heartworms is Dr. Susan Wayne, Murphy’s Vet. Clinic in Sanford, FL. However, if anyone has a vet that they would like to recommend, please email us and we will post it here, and on the blog.

Here’s the stuff I’ve heard:

– Someone’s dog died on immiticide because they didn’t keep it quiet. The immiticide treatment killed her.

– A friend of mine did the slow kill method, and the dog died.

– I used ivermectin, and my dog died.

Let’s get real here, it’s heartworms that kills dogs.

Let’s get real here, it’s heartworms that kill dogs. The overall health of your dog, your dog’s age, the load of heartworms, and breed are all taken into consideration. You have the right to review all methods of treatment, and choose the method you think is best for you, your dog, and your pocket book. In the case of Collie Girl, Gisele, there were no options. Her condition and load were both severe. She had to be nursed back to health, for two months before she could go through the fast-kill immiticide treatment. Her load was so heavy, that the slow kill method would not have been affective for her, for she was simply running out of time before the heatworms would kill her.

In the case of Jackson Browne, and many other dogs that I have rescued, they were young, healthy, had a light load, and were treated using the slow kill method, by monthly heartgard. Jackson Browne’s high energy level immediately disqualified him as a candidate for the fast kill method.

I strongly recommend you review this entire article by Dog Aware, which breaks down the disease itself, and stresses the use of Doxy.

In this article, focusing on the treatment of the disease, provided by Dog Aware, both the slow kill and the fast kill method are detailed. Also provided is information regarding different forms of monthly heartworm preventative, and which ones are affective at killing the heartworms.

Controversy: This article clearly states – “Whenever heartworm treatment is delayed, for whatever reason, it is usually a good idea to start the dog on monthly Heartgard in the meantime, which will help destroy the microfilariae and weaken the adult worms. Because there is a small chance of an adverse reaction to this treatment, it should only be done on a day when you are home to observe the dog and seek treatment if necessary. Do not use Interceptor (milbemycin oxime), which is much more dangerous to a dog with heartworms, due to its greater efficacy against microfilariae. ”

Question: Then why is it some vets refuse to give me heartgard for a HW+ dog? What are they thinking?

The Author’s final recommendation: “Based on the research below, I recommend giving weekly ivermectin (Heartgard) along with doxycycline prior to treatment with Immiticide (unless your dog has the MDR1 gene mutation that causes sensitivity to ivermectin). If Immiticide is not used (slow-kill treatment method), then I recommend giving weekly ivermectin along with pulsed doxycycline (see the schedule below) for at least a year, or until the dog no longer tests positive for heartworms (note that a dog may test positive for up to six months after the worms are all gone).”

Here’s an overview about Ivermectin and Collies: “Approximately 35% of Collies have a genetic mutation creating a non-functional P-glycoprotein. This allows for ivermectin doses that would normally be blocked from the central nervous system to gain access to it. Other herding breeds as listed above also have a tendency to express this mutation. There is now a test for P-glycoprotein mutation so that ivermectin sensitive dogs can be identified. This is a DNA test using an oral swab. Test kits can be ordered directly from the Washington State University Veterinary School via

Here is a post we kept up with while Collie Girl, Gisele went through her heartworm treatment, and we also received updates from other adopters about their treatment plans as well. The Diary of Treatment Heartworm Disease.

7 thoughts on “Everything You Wanted to Know about Heartworm Disease

  1. This is great information, especially since HW+ status seems to scare many people away from adopting dogs. It also emphasizes how vitally important monthly heartworm medications are to ensure the continued good health of your dog.

  2. The following was posted on The Dog Liberator Facebook page by Trisha Adamson Riggins:

    We adopted last year and our dog tested hw pos after a year and he was on preventative bc I gave/give to all my dogs ademently. It was interceptor. Intercptor is awesome but if u have a rescue should consider heard guard for first year as i…t kills larve at a different phase of their larval stage. I learned a ton, we did the new protocol for hw slow kill and just finished . We are in the build heart up and play slow and then n a few weeks will be back to normal. It is slow process but all will be well forever now. Hw is treatable and preventable. Knowledge is poweful and we thought we would never be in that position bc he was on preventative since day one of rescue without deviation. It was the type he was on and lack of knowing his history. So hw pos is not something not fixible and can be prevented with knowing some of the research. Now if he tests neg in six months than a year, he can go on any preventative. For now has to stay on heart guard at least six months bc only stage possible since treatment is early larval tha only heard guard can. There is a ton of info on which larval stages which hw preventative kills. Hopefully people can learn bc we never at all expected to hear…he is hw pos when he tested neg twice when we got him and was on preventative. Cool thing is we did tons of research as to if u do not know history dog might test neg but as stray…..larva were too small to show pos. They they grow u think u r good bc on something that does not kill larva that stage, then they keep growing and then finally show. Hw pos is not fav thing to hear but soon as it is found, begin slow kill…do not wait. Age of the dog and how bad is infection are considerations as well……anyway it is treatable and preventable. If dog was stray but tested neg….give heart guard…..that is what I leanred. Then if they test neg after one year can do Interceptor or whatever else. It is not the drug that is bad at all…all rock. It is knowing history and what stage u need to kill that is key.

  3. I found d my dog in the street 2 years ago, she tested HW negativeat I’ve at that time and although she has been on trifexis for one year she he’s turned HW positive,. She is an otherwise healthy 2Y/O AT 66.1 POUNDS sherpherd/lab mix…BLONDIE, SHE is very active however does show some increase in respiration after exercise but recovers fairly quick. The doctor has recommended this treatment as Im disabled and don’t have the finance for primary route of treatment and her HW Test showed small # of larvae. I would like to know the dosage and length time required for Co treatment with trifexis or other HR PREVENTIVE med for use of doxcycline. I understand the limitations of exercise during treatment and the nwe’d for indoors is not a problem . As I said she has been on trifexis and does t show any complications from it… please help me as I would like to rid my dog of this deadly parasite

  4. we adopted a heart worm positive dog last year. he’s been on the slow kill method of hw preventative and pulsed doxycycline for 15 months but we still got a positive high on his heart worm test. i would have hoped even if we were still positive that it would be a mild positive. why is the treatment not working for him?

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