Heartworm in Dogs: Everything You Should Know

An informative look at heartworm in dogs. Heartworm in Dogs: Everything You Should Know thegearhunt.com

While heartworms in dogs might be easy to prevent, they can also be both costly and difficult to cure. Let’s take a quick look at some information regarding this malady.

How Do Dogs Actually Get Heartworms?

Dogs can only get heartworms if they have been bitten by a mosquito that was infected. There isn’t any other way for them to get it. Also, there isn’t any way to tell if the mosquito is infected. Because of this, it is important to prevent it from happening in the first place.

Heartworm disease is something that has been occurring in all 50 states. Also, it only takes a single bite from one mosquito that has been infected with the larvae of heartworm to give the dog this disease.

Heartworm disease has spread throughout USA, but it is also being found in places where vets could previously reassure their patients that heartworm disease was not a possibility due to their location. Think about places like desert areas, Arizona, California, and Oregon, where building and irrigation are allowing populations of mosquitoes to flourish. If there are mosquitos present, and you own animals, heartworm is a definite concern. It is as simple as that.

All it takes is just about 7 months after your dog has been bitten by a mosquito that was infected for the heartworm larvae to grow into heartworms that are adults. Once they are mature, they will lodge themselves in the lungs, heart, and the blood vessels that surround these organs and they begin to reproduce. An adult heartworm can grow to a length of 12 inches and has a life expectancy of as much as 7 years, and dogs can have as many as 250 of these worms in their bodies.

Can Humans Get Heartworms From Their Pets?

Heartworm is something that can only be transferred by mosquitoes. This is a very specific parasite that only affects ferrets, cats, dogs, and other mammals. There have been rare cases where people have been infected by heartworms, but even then, the heartworms aren’t able to complete their entire life cycle. These worms migrate to the lungs and then cause there to be a circular lesion that appears as if it is a tumor. However, these cases are incredibly rare.

If One Dog is Infected, Can He Pass it to Another Dog?

Not at all. The only way that heartworms can be transmitted from one animal to another is through the bite of a mosquito that has been infected. Additionally, even if a mosquito that is not infected bites a dog that is infected and then bites another uninfected dog all in the same night, that mosquito wouldn’t be able to transfer this parasite from one animal to the next. This is due to the fact that once a mosquito bites an infected creature, the heartworm will need to go through a period of incubation inside that mosquito before the mosquito will be able to pass it on to another animal.

Is Adopting a Dog That Has Heartworms ok?

This is an issue that is becoming more and more common at animal shelters, and these public shelters often don’t have the funds to treat this disease. It is perfectly fine for you to adopt a dog that has heartworms, but you also need to dedicate yourself to getting this disease treated correctly. If it isn’t treated, the disease is one that is awful and can actually lead to the death of the animal.

How Can You Prevent Your Animals from Getting Heartworms?

If you go to Starbucks at least once a week for coffee, you will know what that costs. You can be able to prevent your dogs from getting this disease for even less than that. There are products that include injectable, topical, and pill prevention products. The injectable prevention is a 6 month one. The topical is meant to be put on the dog’s skin once a month. The pills are also a once a month thing. The damage that will be done to your dog and the cost of treating the heartworms once they have infected the animal are considerably more than what it costs to prevent it altogether. Heartworm preventative for a year will cost about $80 or less. This will depend on how much the dog actually weighs.

What Are the Symptoms of Heartworm in Dogs?

At first, there won’t be any symptoms at all. However, as more and more of the worms crowd into the lungs and heart, most of the time, the animal will start coughing. If it progresses, they will not be as active as they normally are, and it will be easier for them to get winded. Once heartworm disease becomes severe, your vet will be able to hear sounds from the lungs that aren’t normal, the animal can actually pass out from them not getting enough blood to their brain, and they can begin to retain fluid. If the disease isn’t treated, the dog will eventually die.

If a Dog has Heartworms, How Much is Treatment?

There are only a few options for treating a dog that has heartworm disease and all of them are injectable. The animal will be given 2 or 3 shots that will obliterate the adult heartworms that are in the heart’s blood vessels.

The absolute safest way to treat dogs with heartworms will include a quite extensive workup before treatment. This will include things like blood work, X-rays, and all of the various tests that will be needed in order to determine how serious the condition is. The dog will then be given injections. With all of this work and testing, the cost can be as much as $1,000. However, the treatment itself can be done in some areas for around $500.

Why is Keeping the Dog Quiet During the Months of Treatment Important?

Once the animal has been treated, the worms inside of it will start to die. When they die, they will break up into smaller pieces, and these pieces can actually cause a blockage in the pulmonary vessels that can lead to death. This is the reason for them to need to be quiet not only while they are being treated, but also for quite a few months after. There have been studies that have shown that when dogs die after being treated for heartworms, it is because the owners allowed them to exercise. These deaths are not attributed to the drugs used for treatment at all.

If a Dog is Diagnosed with Heartworms, Why Can’t They just be Treated with the Monthly Preventative as Opposed to Having them go Through Treatment?

Studies have found that if you utilize ivermectin, which is a common preventative, each month in a dog that has heartworm disease, after nearly 2 years, you will be able to kill most of the young heartworms. That being said, all of the time that is passing while you are using a preventative to treat it, these heartworms are using their time to permanently damage the blood vessels and heart.

However, if this is more affordable than the treatment, by using the monthly preventative, at least it could be considered a lesser alternative.

Should You Skip Giving the Preventative During the Cooler Months When There Aren’t Any Mosquitos?

According to the American Heartworm Society, AHS, heartworm prevention should be given all year long. One reason for this is that there is already a big issue with people forgetting to give these preventatives. This is a problem that is universal. However, if you use it all year long, and you happen to forget one month, the animal will still have been protected. That being said, if you miss more than 2 months, the dog is left vulnerable to being infected.

The other reason for not stopping is because many of today’s preventatives also contain intestinal parasite control for things like tapeworms, whipworms, and roundworms. All dogs need to be protected from these parasites all of the time.

If the Dog Isn’t Treated for Heartworms, Can It Outgrow Them?

Not at all. He will end up dying from the disease – a very slow and painful death.

Rumors Abound That Heartworm Treatment Can Be Dangerous. Is There Any Alternative Thatis Safer?

It used to be that plain old arsenic was used to treat heartworm disease, and this had quite a few side effects. What is used currently is the safest product and causes far fewer side effects. If it is used correctly, it is safe.

If a Dog Gets Heartworm Disease, and Gets Treatment For It, Will He Be Susceptible to Getting it Again?

In a word, yes. They will always be susceptible to it, whether or not they have already had it. This is the reason that prevention is so critical.

What is Heartworm Disease Really?

This disease is caused by a parasite called Dirofilarial immits, which is actually a sort of roundworm that makes its home in the blood vessels of the lungs and in the heart. This disease is transmitted by mosquitos, as mentioned above. It should be taken seriously because it affects the lungs and heart and it has also been known to affect the central nervous system, eyes, kidney, and liver, and if it isn’t treated, it can and will lead to death.

A Closer Look at Symptoms

Symptoms of this disease can be subtle, and that can make them quite easy to overlook. When the number of these parasites increases, the dog can show symptoms like weight loss, lack of appetite, intolerance to exercise, lethargy, and coughing. These symptoms will become more and more apparent as the disease progresses. That being said, it is always best not to wait until symptoms develop before having your animal checked out because permanent damage may have already occurred.

Where is the Largest Risk?

This disease has already been found in every state in the US. However, it seems to be more prevalent along the Mississippi River and in the Southeast. Studies that have been conducted by the AHS have determined that this disease is increasing across the country. Most people know that it affects dogs, but many might not be aware that it can also affect cats. At one time, it was thought that cats had a resistance to infections by heartworms, but studies done recently have proved that this is simply not true. Cats and dogs both can get the disease. In all actuality, any animal that gets bitten by an infected mosquito can be infected with this particular parasite. You need to have a conversation with your vet regarding the risks to your pet and how you can protect them.

Being Diagnosed

This disease is diagnosed most often by blood tests that are able to detect the presence of the parasite. Many vets run these simple, fast tests right in their clinics and will be able to tell you within only a few minutes whether or not your animal has been infected. Depending on the results of the test, and any symptoms that the animal is presenting, things like a cardiac ultrasound, radiographs, and more lab tests may also be recommended in order to determine both the infection and the severity of it.


The very best method of treating heartworm disease is to make sure that your pet doesn’t become infected in the first place. It is a good thing that there are quite a few effective and safe preventative medications that are available from vets in a few different forms. There are oral, injectable, and topical preventatives. Along with protecting your animals from this disease, many of the preventatives are also able to protect them from other internal parasites. This is critical due to the fact that it also helps to prevent the parasites from being spread. This means that not only are you protecting your pet from heartworm disease, you are also giving yourself the peace of mind that comes with knowing that they haven’t picked up any other parasites, such as roundworms, that they can transmit not just to your other pets, but also to you. Finally, before you start giving a preventative to a pet that is over 6 months old, you should have your vet check them for any existing heartworm infection due to the risk of serious complications developing if an animal that is infected begins taking certain preventatives.

If you happen to have any concerns or questions, call or go to your vet’s office. They are always the best resource when it comes to ensuring the well-being and health of your pet.


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