In the course of reading up on heartworm and heartworm treatment, which I did when the test result was positive in mid-April, I considered the ‘alternative’ methods of treatment, and it took me remarkably little time to reject them. First I looked at Paratox, which is a homeopathic preparation that is given in conjunction with heartworm nosodes; I read about claims of successful treatment of heartworm-positive dogs with it, but I was skeptical. I don’t believe that homeopathy is anything other than a placebo effect, and sometimes not even that. I’ve never had success with homeopathic remedies given to my dogs for anything, and I wasn’t going to go into a life-or-death situation like this one and pin my hopes on homeopathy.
Next I read about the ‘slow kill’ method, which consists of giving ivermectin (Heartgard) monthly to kill microfilarae and at the same time, just waiting for the adult worms present to die over time. This boggled my mind. If I felt like I was having a nervous breakdown over one month of living with worms in my dog’s heart, how could I do that for several YEARS? And the more time the worms live in the dog’s body, the more damage they do, to the heart and the lungs and other organs. No, slow-kill wasn’t an option. The more I read about it, too, the more I found reports of slow-kill methods taking as long as five years to eradicate all the worms – five years before my dog would be heartworm negative? Seriously? No.
So I ended up back where I started: at the American Heartworm Society protocol, which we followed and are following, step by step.
False positives do happen, so the first step was to verify the test result. The same blood sample that had produced the positive on the IDEXX antigen test was run through a microfilarae test, to see if there were any immature heartworms in his blood: the antigen test had indicated the presence of the hormone of adult female heartworm(s). If the microfilarae test were to show immature worms, the positive result would be confirmed. But it didn’t. No microfilarae in Rowley’s sample. “Yay, it’s a false positive!” I said hopefully to our vet; he had already drawn another blood sample from Rowley and was running it through another antigen test even as I spoke. This one also came back positive, dashing my hope of a false positive on the original test.
So we had adult heartworms but no immature heartworms. That’s good! (Well, ‘good’ may be overstating it … how about just ‘less awful.’) The next step was a physical exam to see if any irregularities were noted in Rowley’s heart sounds, and a chest x-ray to see how his lungs looked; we also did bloodwork to make sure everything was in order. Without microfilarae we hoped for good results from both those things, and we got them. He showed no signs of his heart or lungs being compromised – yet – by the worms. His bloodwork was excellent. Rowley’s was a Stage One infection, and we could have every expectation of an entirely successful treatment. Okay, so let’s kill the bleeping things! — Not so fast. A step in the treatment of heartworm, added a few years ago, is to administer doxycycline for one month before the Immiticide treatment, in order to destroy the wolbachia bacteria that accompany the heartworms and facilitate their survival in the dog’s body. I read that antibiotic therapy directed against Wolbachia leads to decreases in all stages of immature heartworms and might decrease numbers of adult heartworms as well. And because the presence of wolbachia often contributes to a significant, and often dangerous, inflammatory response seen in some dogs, treating with doxycycline can decrease complications associated with heartworm disease both pre- and post-treatment. It wasn’t a step we would skip, so Rowley started taking 10 mg of Doxy per pound of body weight per day. Even though I offset this whopping dose with daily probiotics and saccharomyces boulardii, by week two I was having to trick him to get the Doxy into him – it’s not a pleasant substance. In week four he stopped eating kefir, which was one of my most frequent hiding places for the antibiotic, and it’s only now, several weeks later, that he’ll accept kefir in his food dish again. And in addition to the doxycycline, Rowley started on a monthly course of Heartgard, to kill any microfilarae that might find their way into his body.
That was a really long month. There were worms living in my dog’s heart, and every single day I was conscious of that fact. I had started to reduce his exercise, pulling him from his twice-weekly agility classes and substituting leash walks for some of our trips to the nature preserve where he always bounded about off-leash. Neither of us liked the change to our routine, and I wanted those worms DEAD. I was actually relieved when the day came for his first shot of Immiticide. Of course, my relief alternated with a terror that the Immiticide shot would kill him, but what options did we have? To anyone who has never gone through the process of heartworm treatment in one of your dogs, I can say only: you never want to repeat it. You don’t even want to be doing it at all!
I dropped Rowley at our vet clinic in the morning and returned to collect him late that afternoon. He received the shot at about 9 a.m. and our vet called to tell me that all had gone well, there had been no problems and indeed, Rowley had been very cooperative. This is pretty amazing because that shot’s a nasty one: it’s a deep IM injection given in the lumbar (back) muscles. It’s a lovely compound that features arsenic, and it’s a carcinogen. Wow, could this get any better?! When I picked up my dog that evening, he had a square shaved patch on his back at the injection site. It looked like someone had stuck a Post-It on him. He’d been given Benadryl before the shot and generic Rimadyl after, and he had some more generic Rimadyl to take home, since we assumed his back would be sore. It probably was – and boy, was he tired! If I know Rowley, and I do, he didn’t sleep in the kennel at the clinic at all. And judging by the ten-minute leg-lift in the back yard at home, he didn’t relieve himself there at all either. There’s no place like home! He went right to his bed and zonked out. An hour or so later, he showed up in the kitchen when I was putting the dogs’ dinner together; he ate every bite – no doxycycline in it for a change! – and went out again to relieve himself and then went back to bed.
The relief I felt that a killing blow had been struck against the worms was enormous, and it was magnified by the fact that Rowley seemed to have handled the whole thing remarkably well. Whew! And in a perversely positive note, I requested and received an exemption from the requirement for any more rabies vaccinations for Rowley. Illinois is one of many states that now allows medical exemptions from rabies vax requirements if a veterinarian will state in writing that the administration of that vaccine would be harmful to the health of the dog. I felt, quite reasonably, that if I had to have my dog injected with a carcinogen in order to kill his heartworms, I sure shouldn’t have to have him injected later with a rabies vaccine that might have the effect of dropping a lit match into a pool of gasoline. So the request was made and granted, a short time later, by the County Department of Public Health.
Then came the lesser challenge of the treatment: keeping him quiet. More about that in the next post.