What is the cycle of heartworm, and how will this information be beneficial to the treatment of my dog?

As I said, we have the adult heartworm, and then we have some larval stages. And so often, when you think of heartworm and talk to your veterinarian, we're talking to you a lot about heartworm prevention. And what we're trying to do with that prevention is kill the larval stage of that heartworm so that it never develops into an adult worm that lives in the heart. Whereas when we diagnose a pet with heartworm disease, it's because we're picking up those adult worm antigens that are living in the heart or maybe the pulmonary vessels—the vessels going to the lungs. And we do a separate protocol for the treatment of those adult worms.

That's a good question, too, because it actually gets into the core of how heartburn prevention works. What exactly is it doing now? Essentially, a mosquito will bite an infected dog and then transmit it. It will go through a series of stages of development, a couple of stages that avail within a mosquito. Then the mosquito bites an unprotected dog and squirts this larva into the dog as it's sucking out the blood, in which case, there's more larval development inside the dog. Then it develops into adult heartworms, which live primarily in the heart but can also migrate into the lungs. How does heartworm prevention work? How does that fit into this whole sequence? When we think of heartworm prevention, we think we're preventing getting it in the next couple of weeks or six months. But it actually works backward. It is working to protect or eliminate any of the heartworms, the development, or the larva the previous 30 days when we're giving the once-a-month medication. If we're giving the medication, it works backward over the last 30 days. That's why it's imperative that you've got to keep your dog on prevention once a month. Don't try to cheat and go every 45 days or certainly not every couple of months because you're missing that window when the larva can develop and go on to the adult stage. Again, if you're going to start with prevention, be consistent. Make sure you're giving the medication every single month, about every 30 days. Let's be precise, how about every 30 days? If you get it every 30 days, your dog's going to be protected. But if you start skipping days and if you forget to give it, that's when we can run into problems. That's why we do have a six-month injection, and a 12-month injection for situations where we forget to give it or your dog doesn't really like to take the chewable tablet. We also have one topical liquid for people who don't want the injection or if their dogs won't take the chewable tablets. So essentially, that's the life cycle. The cycle starts when the mosquito bites an infected dog and sucks its blood. The larva develops, and the mosquito transmits it to an unprotected dog through a mosquito bite. Then the cycle just keeps on going that way. So please, the take-home message is to make sure you give your dog heartworm medication when it is supposed to be given.

The cycle of heartworm starts when the microfilaria, which is found in the parasite, the mosquito, is injected into one dog, and microfilaria then slowly reaches different stages. There are actually six larva stages before it reaches the adult stage. Depending on the number of heartworms, we'd use that to determine how we stage the pet based on the size of the heart and the vessel issues we see.

The cycle of heartworms starts when a mosquito carrying the infected larva bites your dog and deposits the infected larva into the tissue. The infected larva then spreads to the heart, where the adult heartworm develops. Heartworm preventatives help clear the baby heartworms or infected larva, but none of the preventatives treat the adult stage.

Heartworms have multiple life stages. They start as larvae, known as microfilaria, which live in the bloodstream and then move to the heart. These larvae are usually picked up by mosquitoes and then transmitted to another dog. This larva that circulates through the bloodstream goes into the heart and takes about six months to develop into a fully mature adult heartworm.