Heartworms in Dogs - Symptoms You Should Know How to Know if Your Dealing With Heartworms in Dogs

Heartworms in Dogs - Symptoms You Should Know
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vet verified PetCareRx Staff Veterinarian DVM

Early detection of heartworms can protect your dog from serious illness or worse. Read about heartworms in dogs and how to combat them at PetCareRx.

Most dog owners show their love and affection for their furry friends by playing fetch, giving treats, and daily hugs and attention. But the most important way to show you care for them is by protecting them from heartworms in dogs with preventatives like Sentinel Spectrum, Sentinel for dogs, or Tri-Heart Plus. Find out what heartworm symptoms look like and how to deal with them.

Cause of Heartworms in dogs

Heartworms are large parasitic worms that live in the bodies of dogs, cats, horses, and other animal species. Over time, these unwelcome intruders attack the animal's veins, liver, lungs, heart, and other vital organs. The most common animals infected are dogs. The carrier culprits are mosquitos. Heartworm larvae are injected by the mosquito into the bloodstream of the dog and mature into adult worms that can live up to 7 years. One sting is all it takes from an infected mosquito, and your beloved pup could be in danger.

It is a common myth that heartworms only affect animals in specific states. The truth is that mosquitos have been reported in all 50 states, and where there are mosquitoes, there are heartworms. Because it is impossible to know if a mosquito is infected with the disease, it is of utmost importance to take preventative measures to protect your dog from this serious and potentially fatal disease.

Many families have more than one dog and often wonder if heartworm disease can be spread from pet to pet. Luckily, the answer to this question is no. Heartworms are only transmitted through the bite of an infected mosquito. Therefore, the only dog affected will be the one who suffered the infectious sting. There should be no worries about your dogs sharing food or water, dog bowls, toys, dog brush, or play areas. There have also been very few human cases of heartworm reported.

Heartworm Symptoms

There are some clear signs and symptoms of your dog having heartworms. Initially, a dog may show no apparent signs, but over time, the dog may develop a mild to severe cough as the worms begin to crowd the lungs and heart. Dogs may also become worn out and winded more easily and engage in less physical activity than before. Usually, playful and energetic dogs may begin to lie down instead of running to fetch or leap upstairs. Another heartworm symptom is weight loss, lack of interest, or fever. A lack of appetite or jaundice may also be clear signs of the presence of heartworms. In the final stages of the disease, a dog may collapse or pass out from a lack of blood in the brain. At this point, it may be nearly impossible to save the pet.

Prevention and Treatment

As a pet owner, you have two options when it comes to heartworm and your dog: prevention or treatment. Prevention, of course, should be the obvious choice and will save you hundreds of dollars in the long run. You can choose between pills, topical ointments, or injections for your dog that will run under $100 per year, depending on the dog's weight. Popular brands of heartworm medicine are Heartgard for dogs, Heartgard Plus, Sentinel, Iverhart, Interceptor, Interceptor Plus, and Trifexis

An investment in one of these products could mean saving the life of your pet. However, if a dog is infected due to a lack of preventative care, the results may be devastating if not treated soon after heartworm symptoms arise. The treatment for heartworms will cost approximately $300 to $1000, which may include x-rays, blood work, tests, and injections. The treatment is a lengthy process that requires a dog to be contained for up to 6 weeks. It is not guaranteed that all dogs will survive heartworm treatment, but if caught early enough, treatment is usually successful.

According to researchers, only about 50% of dogs in the U.S. are on some sort of heartworm preventative medication. Not only are preventative measures significantly more affordable than treatment after the fact, but part of showing care and compassion for your pet is sparing them from potentially dangerous and/or fatal diseases. 

Preventative medications have been proven to be 99% effective, and many of them also prevent other types of worm infections. Giving dogs regular preventative medications are a sure way to show your pet you care about their health, safety, and well-being.

How to Prevent Heartworm in Dogs

As with most parasite-borne illnesses, it is far easier to prevent heartworms than to cure an infection. Treating your dog for heartworms can be a costly and extended process. Without preventative drugs, there is a very high probability your dog will get bit by a mosquito carrying heartworm larvae and receive the disease.

How Do Preventative Heartworm Treatments Work?

Preventative heartworm medication for dogs is available as spot-on treatments, shots, or monthly pills. Many of these treatments will also protect your dog from other parasites, such as roundworm and fleas. Regardless of how the medication is given, there is no way to stop dogs from exposure to larvae following a mosquito bite. Rather than warding off the disease, the medicines act as an insecticide. The preventatives destroy the larvae, preventing them from growing to adulthood and reproducing.

Why Year-Round?

Preventative medications are generally used year-round, even in places where mosquito season only occurs for a few months out of the year. It's far easier to keep on schedule with medication when giving it on a routine basis. Keep in mind that preventative treatments do not destroy adult heartworms, so a yearly test is recommended to double-check that your dog has not contracted heartworms despite the use of preventative medication.

Medication Options

There are several options available for preventing heartworms. The FDA-regulated drugs are available by prescription only, which is partially due to the need to test dogs for infection before giving a preventative. The following are the major preventative medications available:

  • Ivermectin – These chewable tablets are sold under the brand names HeartgardIverhart, and Tri-Heart Plus and need to be taken every month. In addition to killing the developing microfilaria (baby heartworms), these drugs also protect dogs from roundworms and hookworms.

  • Milbemycin Oxime – Available under the brand names Inceptor, Milbemax, and Trifexis, these monthly tablets control adult hookworm and roundworm infections as well as destroy larval heartworms.

  • Selamectin – Sold under the brand name Revolution for dogs or Revolution Plus, this drug is a topical ointment that is applied every month to the skin by your dog's neck. This treatment also kills adult fleas, mites, and ticks.

  • Moxidectin – This drug is sold under the names Advantage and Proheart. The Advantage multi dogs treatment is given topically every month and Proheart 6 is available as an injection, which is administered every six months in your veterinarian’s office.

Missed Dose?

If you miss a dose of a medication, give it to your dog as soon as you realize it. Avoid giving two doses at one time, however, and if you miss two months, let your veterinarian know. The vet may want to test your dog for signs of heartworm in six or seven months when the infection would be detectable.

Factors That Affect a Dog’s Risk for Heartworm Diseases

Your dog's risk for heartworm disease depends on several factors, including:

Age: A puppy or kitten is at the highest risk because they haven't been exposed to heartworm before and may not have built up immunity to it.

Weight: The heavier the dog, the greater chance that it will develop heartworms (since this increases blood flow).

Gender: Female dogs are more likely to be infected with heartworms than males because of their faster reproductive cycle and higher rate of reproduction.

Breed/type: Certain breeds are more susceptible than others; for example, German shepherds tend to have a higher prevalence of these parasites than mixed-breed dogs do. But any breed can contract them if they aren't kept free from mosquito bites and infected other animals' saliva when playing outside!

Never Ignore Any of These Signs 

Heartworm prevention is safe and effective, except a small number of dogs may suffer an allergic reaction to the medicine. If you're in doubt about your dog's reaction to heartworm prevention, talk to your vet about having him tested for allergies, and if necessary, alternate between different types until one works out well.

If you notice any changes in your dog's behavior or physical symptoms, consult with your veterinarian as soon as possible. Heartworm infection can be fatal if not treated early on in its course, so it's important not to ignore any signs that could indicate an infection, such as coughing or difficulty breathing.

We hope you'll take the time to educate yourself on heartworms in dogs and how to prevent them. This is especially important if you live in a state where they're prevalent, such as Mississippi or Louisiana. The best thing you can do for your pet is to learn what signs to look out for so that if something does happen, then it's not too late.

This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis, or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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