Dog being fed heartworm medicine

Dog Heartworm Disease

Dog heartworm disease is something no pet owner wants to deal with—thankfully, it’s a condition that you can easily prevent. It’s also a disease that dog owners should be well educated on, as quick treatment if it does occur is of utmost importance. Perhaps that’s why you’ve turned to the internet for answers. At Veterinary Medical Center, we work extremely hard to make sure you get the accurate information you need. We’ve taken the most frequently asked questions about dog heartworm disease and answered them as thoroughly and accurately as possible so that you can ideally prevent your dog from ever having to experience this.

If you’re looking for a highly trained veterinarian in Union City, CA, we’d love to help you care for your dog and other pets that you have. The first order of business is to get your dog seen right away to get them on heartworm prevention if they’re not already, so please call us at [practice: phone].

What is heartworm disease and how can it affect my dog?

Heartworm disease is a serious and potentially fatal disease that occurs in many parts of the world in which the dog is afflicted with foot-long heartworms, or parasites, which live in the right side of the heart. These parasites cause problems with the blood flow and the sealing of the valves—opening and shutting on the right side of the heart. And the most common thing that we see is respiratory issues because blood goes from the right side of the heart to the lungs. If heartworm disease affects those pulmonary arteries, which it often does, and those worms sometimes try to migrate into the lungs, that migration can cause a lot of respiratory signs and damage to other organs. The dog will often have difficulty breathing and will likely be coughing.

Golden retriever puppy sniffing grass

How would my dog catch heartworms?

The only way for dogs to get heartworm disease is through a mosquito bite—they are a mandated intermediate host. A mosquito bites a dog that has heartworms and picks immature larvae from that dog. This larva has to live and develop in the mosquito for about two weeks, and then it turns into infective larva. So if that mosquito, which now has heartworms, bites a dog that's not on prevention, that is how a dog will develop heartworms. That’s why this disease is thought to be in coastal areas or areas that are very hot. And if the weather by you is variable, it’s likely that heartworm disease is a serious risk year-round.

Can dog heartworms be prevented?

Yes, absolutely. In most areas, there's almost nothing you can do to completely get rid of mosquitoes, at least effectively enough to eliminate heartworm disease. Hence, our way of preventing heartworm disease in dogs is by putting them on heartworm prevention. These preventatives kill the baby heartworms before they can develop into adults. There are plenty of kinds of heartworm prevention methods — including injectables, oral, and topicals—so make sure to talk to us or your veterinarian about what is best for your dog and lifestyle.

What are the signs in my dog that would indicate they may have heartworms?

Mild or low worm burden cases of heartworm disease are asymptomatic, so most veterinarians will screen dogs every year for heartworm antigen, even if they're asymptomatic and have been on heartworm prevention, as we can catch any cases that might pop up.

When an infected dog starts showing symptoms, they typically depend on the stage of the infections, such as:

  • In the early stages, you can see lethargy, coughing, and shortness of breath.
  • Once your dog has adult worms that live live inside the heart, they can do a lot of damage over time. Again, the dog will be coughing, lethargic, and possibly experience exercise intolerance, so they cannot go as long as they usually would.
  • If you have a severe worm burden in the mid to late stages, you can have a dog with congestion in the lungs or the liver, so you could see bulging ribs or abdomen. The dog could also develop a heart murmur because of the worms affecting the function of the heart.
  • In more severe, late-stage cases, infected dogs can have edema or swelling of the extremities, and the abdomen will fill up with fluid. Those are much more advanced cases, but they do happen.

Small white dog being fed heartworm medication

How will a veterinarian diagnose if my dog has heartworms?

The only way that we can easily detect heartworms is by doing a blood test. The female heartworm releases an antigen that we can pick up on in the dog's blood. The vast majority of infections are going to be circulating heartworm antigens in the blood. A small blood sample allows us to detect adult worms, and then we know that the dog is infected.

It's vital to understand the life cycle of a heartworm. When the mosquito bites the dog, it takes five to six months for that worm to develop into an adult worm, and the adult heartworm is what we’re able to detect in the blood. If your dog were infected within the last six months, the heartworm test today would not be able to pick up that heartworm. That’s why if they've been off prevention and are an adult dog, we test them now and then again in six months to ensure they're negative.

Why is early detection and diagnosis of heartworms so important?

Early diagnosis and detection are essential because early detection of adult heartworms often can allow us to intervene and treat the heartworms before they do significant damage to the heart and lungs. And if we can do that, we can usually have long-term success with minimal to no long-term complications.

How is heartworm disease diagnosed?

Initially, we conduct an antigen test, which tells us that adult heartworms are giving off a substance that's screened for in the bloodstream. If you want to confirm that diagnosis, you do something called a microfilaria test, which tests for the larva in the blood. And that tells us you do have an adult heartworm infestation that we need to deal with.

How is heartworm disease treated?

Although somewhat manageable in the early stages, the treatment for heartworm disease is certainly no fun for the dog. We typically do three spinal muscle injections—one on the first day, then one a month later, and one a day later. These injections can be painful, do put them on steroids to reduce inflammation. We also have them on strict activity restriction because as these worms die off, they might give little pieces off into the dog's heart and the bloodstream. And we never want those to cause any sort of clots or other issues. So, the dog's pretty restricted for a couple of months and has to come into the clinic to do all these things, which is why we would much rather your dog not get heartworm disease than have to be treated for it.

How soon should I bring in my dog to see a veterinarian for heartworm prevention?

Your dog should come in as soon as possible. If you have a puppy, we recommend bringing it in as quickly as possible after you get it. We recommend starting puppies on heartworm prevention at eight weeks, or, again, as soon as you have them. Any dog over six months should have a heartworm test before starting for heartworm prevention. All veterinarians will highly recommend bringing any rescues, adoptees, or adult dogs that you might get to the clinic as soon as possible, and we would screen for heartworm and then get them on heartworm prevention.

The AVMA is another helpful resource on dog heartworm disease. If you have further questions about this serious yet preventable illness, reach out to your veterinarian. If you live in or near Union City, CA, we’d love to get your dog on heartworm prevention to keep them as healthy as possible, so please don’t hesitate to call us at [practice: phone] or email us at [practice: email].