what are the signs of heartworms in dogs?
Pet Health Questions and Answers

How to Get Rid of Heartworms in Dogs

Of all the infectious diseases that result from parasites attaching themselves to our dogs, heartworm is arguably the most concerning. It must be dealt with as quickly as possible if you suspect that it’s made itself at home within your dog’s internal organs.

Heartworm is a disease that takes its name from parasitic worms that wrap themselves around a dog’s heart. The result of this, as you can imagine, is a painful time for your poor dog.

It’s crucial to note that heartworm is the name of the disease itself, not the parasites that cause it; those go by the moniker of Dirofilaria Immitis. Semantics are not important – the key thing to understand is that heartworm can and should be avoided. Treatment is available, however, if your pet does find themselves struck down by this parasite.

How Does a Dog End Up with Heartworm?

Heartworm is caused by mosquito bites, meaning that any pooch living in a hot climate is at risk.

When these parasitic insects feast upon Fido’s blood, they leave certain larvae – known as microfilariae – behind. These larvae will proceed to burrow into your dog’s body, where they can live for up to seven years and eventually grow as large as 12 inches in length.

Now, not all of these larvae will automatically become life-threatening. The fact is, your dog may already have a number of them in his or her body already. Over time, however, more of these parasites will find their way into Fido’s body during every mosquito season.

If enough of these larvae are present and your dog’s immune system cannot fight them off, at least one may grow into an adult parasite that wraps around the canine heart (hence the name) and other internal organs. This will ultimately cause a great deal of discomfort as these body parts systematically fail, eventually leading to a tragic and painful demise for your dog.

Can Any Dog Get Heartworm?

Yes, but thankfully there are a handful of caveats that also need to apply:

  • As larvae are involved, the mosquito guilty of causing the heartworm infection must be female.
  • These larvae that cause heartworm will not develop within the mosquito unless it’s particularly hot – usually over 55.
  • The mosquito must then target a dog that has already been infected by heartworm. In biting this pooch, the mosquito will extract the larvae (aka microfilariae) that will then be passed on.
  • The mosquito will provide a home for these larvae, waiting around fourteen days for them to develop.

what are the side effects of heartworm treatment?

When this time elapses, however, any dog is fair game for infection – the bug will be looking for something to snack on.  If it’s your pooch that is chosen, it could take up to seven months before you notice any ill effects in your pet’s behavior.

What are the Signs of Heartworm in Dogs?

Speaking of those ill effects, there are seven typical signs and symptoms of heartworm in a dog.

These are as follows:

  1. Coughing, especially after physical exercise. This may even expand to fainting.
  2. Weakness, lethargy and a general disinterest in playing or walking outdoors.
  3. Loss of weight at a rapid and alarming rate.
  4. Panting and difficulty breathing.
  5. Bulges in the ribs and chest.
  6. Sudden allergic reactions to seemingly innocuous items where none have been previously noted.
  7. Collapsing, seemingly out of nowhere.

If you notice any of these symptoms on your dog, get them to a vet ASAP. Time may be of the essence with heartworm – the larvae take a while to mature, but when they do so, they can wreak havoc on a doggy body in record time.

Be aware, however, that heartworm typically unravels in a canine body over four stages and the very earliest phases of the disease may not come with any visible symptoms. This is why regular testing and preventative measures are hugely important.

These phases typically unfold as follows:

  • Phase I – No physical symptoms.
  • Phase II – Coughing or struggling for breath. Possible lethargy. Heartworm would be diagnosed through a blood test under these circumstances.
  • Phase III – All of the above, but considerably more severe. Your dog will also be less interested in food by this stage and losing weight fast.
  • Phase IV – There is no way of sugarcoating this; a dog with Phase IV Heartworm is dying. Medication will no longer help, and in such a scenario, emergency surgery to physically remove the parasites is the only way to save Fido’s life.

As always, educated is armed in this case – be aware of all of the symptoms of each stage, and seek early intervention if necessary!

Is Heartworm Contagious?

As the disease is only passed on by mosquito bites, a dog cannot pass heartworm onto another canine through play, sharing food or toys, or any other concern that would arise from an airborne virus.

Naturally, however, an area that plays host to a sizable mosquito population could see an epidemic of heartworm if necessary precautions are not taken.

Can Other Animals Suffer from Heartworm?

Yes, very much so – heartworm is not limited exclusively to domestic dogs. Canines provide a natural home for the parasites that cause this disease, however, so any members of this animal family are particularly at risk. This could include coyotes and foxes, so if you live close to such wildlife, you will have to be particularly vigilant about taking preventative measures where it comes to heartworm.

Cats, meanwhile, are also at risk of heartworm – though it takes a different form in felines. Mosquitos may bite a domestic cat and pass on the larvae, but as this animal’s body is hostile to the parasites, they will typically not survive into adulthood. Even a young and immature parasite could cause difficulty breathing though, so a vet should investigate any strange behavior from your cat.

Can a Human Get Heartworm?

It’s possible for a human to contract heartworm from a mosquito bite, but it’s extremely rare – and even if we do, the larvae do not live long enough within your body to complete the cycle of sickness.

There is no way that a dog could pass the condition on to their owner either, so there is no need to quarantine a canine that has the condition. This, in turn, means that there is no reason to prolong their suffering – seek medical attention immediately if you suspect that your dog has been exposed to this awful disease.

What Should I Do if I Suspect My Dog Has a Heartworm?

Seek professional advice! Heartworm is not something to trifle with, and if you have any reason at all to suspect that your dog is living with this condition, they should be rushed to a vet ASAP.

Any animal healthcare professional will be able to run many blood tests on your dog to confirm or deny if they have been struck down with heartworm. It’s much better for all concerned if the infection can be avoided in the first place. Heartworm treatment can be intrusive, painful, long and expensive.

How Long Can a Dog Live with Heartworm?

This depends on the severity of the condition. A mild case can be dealt with almost naturally by allowing the existing worms to reach the end of their lifespan and prevent anymore for infesting your dog, but this isn’t advisable.

is heartworm contagious?

Overall, every case of heartworm is different, and there is no definitive answer as to how long an untreated dog will survive without medical intervention. One thing is known, however – ignoring heartworm will place your dog in a great deal of avoidable pain and discomfort.

How Can Heartworm Be Prevented?

Preventing heartworm is a much better approach than waiting for it to strike and then attempting to eradicate the problem. Avoiding any contact with mosquitos is easier said than done, especially if you live in a warm or sub-tropical climate, but thankfully, there are many ways that any dog owner can minimize the risk of infection.

These include:

1) Mosquito Repellent

This should not be used single-handedly, as no such treatment will prove to be entirely effective, but there are many ways of making your dog less appealing to a passing mosquito. This could include picking up an OTC, topical treatment from a pet store, or using a natural ingredient that is known to deter these bloodsucking bugs.

These three most impactful options on this front are –

  • A combination of Geranium Oil and Soybean Oil
  • Citronella
  • Lemon Eucalyptus Oil

2) Vaccination Shots

ProHeart 6 (aka Moxidectin) is approved by the FDA, and thus will be available from almost any vet. Be aware that a vet must administer the shot, though – this is not an OTC treatment – and it will not be available to puppies or dogs over seven years old.

A ProHeart 6 shot will protect a dog for six months, but it won’t prevent other infestations such as roundworms, hookworms, and whipworms. Ensure that your dog will not suffer a reaction to the shot either, as some canines react poorly to the treatment.

3) Oral Pills

Arguably the cheapest and easiest solution for preventing heartworm from taking hold in your pet is to use oral pills, which will kill any larvae before they have the chance to grow and develop into adult parasites.

You can pick these up from any pet store and drop them into your dog’s dinner, so they are consumed without Fido even realizing that he is taking medication. Oral pills won’t last as long as a shot, but this may be fine for a climate where mosquitos are not present for particular seasons.

Speak to your vet if you’re not sure which particular treatment is best for your dog, though in most cases a professional will recommend either Heartgard or Ivermectin, both of which are readily available.

4) Holistic Treatments

If you prefer to take a natural approach, you could consult a homeopathic veterinarian and natural treatments for preventing heartworm in your dog. This approach will avoid any potential side effects of the medicinal approach, but it isn’t for everybody. Make sure that you understand what it means to eschew conventional medicine and the impact that it may have on your pet.

Regular Testing

Take your dog to the vet at least once per year for a full check-up, including testing for heartworm. This is just a simple blood test, and it could save a lot of expense and heartache further down the line if it identifies the disease at a very early stage, before symptoms have started to manifest.

How to Treat Heartworm in Dogs

If the results are in and you’re led to believe that your dog has heartworm, there are many steps that will need to be taken to treat the condition.

These are as follows:

  • Get a Second Opinion. If your dog does have heartworm, you’re staring down the barrel of a lengthy recovery period with a hefty bill waiting for you at the end of it. See a second vet if necessary, and make sure beyond all doubt that the diagnosis is correct.
  • Don’t Allow Fido to Exercise Too Much. If your dog has heartworm, any physical exercise will only aggravate the problem, and potentially lead to them collapsing. How much exercise your dog will be able to enjoy will depend on how far along the heartworm is within their body.
  • Prevent the Problem from Getting Any Worse. This ties in with the step above – many vets will not begin the process of treating heartworm until they are quite confident that it will not progress any further. This means that you’ll have to keep your dog calm, and possibly undergo many initial treatments before the real work begins.

Once this has been completed your vet will start the process of treating your dog’s heartworm.

Medical Treatment for Heartworm in Dogs

The most popular medical treatment for heartworm is called Immiticide, and it’s not much for either dog or owner.

Immiticide, which contains traces of arsenic, is injected straight into your dog’s body – usually in two separate treatments within a 24-hour period for an intensive treatment, or three over the course of a month. After a month, if the treatment is deemed successful, there will be a course of Ivermectin to kill off any larvae that remain.

is treating heartworms painful?

The good news is that this will kill the adult worms that are infecting your dog almost straight away – it is arsenic, after all. The bad news is that, in doing so, these worms start to decay and find their way into your dog’s bloodstream and lungs. This means that your dog may end up coughing up blood, or worse.

Once a treatment course has been successfully completed, your dog will be expected to attend regular check-ups to ensure that the problem has not returned.

Is Treating Heartworm Painful?

Yes. Not only does the injection involve an arsenic compound, which will always cause a reaction, but it also has to be administered to the canine’s lower back. That means that your dog will be left in a great deal of pain in the short-term, but it may mean that they struggle to use their back legs for a few days afterward.

What are the Side Effects of Heartworm Treatment?

As we have just covered, there is always a risk of a dog coughing up blood after a dose of heartworm treatment, maybe even leading to blot clots inside their body, and they may find that their lower back and hind legs ache.

Your dog will require regular supervision from a vet throughout their recovery process, so be sure to discuss any possible side effects at their first warning sign. The side effects of heartworm treatment typically peak after a week or two, so it’s particularly important that you’re vigilant about watching Fido during this period. If your canine companion is vomiting, gagging or coughing, get them some medical attention ASAP. This will be a result of the dead worms reluctantly leaving their system, and help may be required.

If a dog has been provided with the correct dosage of medication to prevent heartworm, there should not be any side effects, especially if you have checked with a vet to ensure that there are no allergies to contend with.

However, some dogs may experience the following:

  • Vomiting and Diarrhea
  • Hives and Itching
  • Loss of Appetite
  • Lack of Coordination or Mobility
  • Seizures and Convulsions
  • Lethargy and Depression
  • Excessive Drool

If your dog exhibits any of these symptoms after taking a preventative medication, speak to a professional for advice on switching them onto something else.

How Much Does Heartworm Treatment Cost?

This depends on just how much treatment is needed – which, again, depends on how far the disease has progressed within your dog.

It is safe to say that anybody looking to undertake a full course of heartworm treatment for their dog should be prepared to hand over at least four figures. We did warn you that heartworm treatment doesn’t come cheap. This will cover the medications required to treat your pet, and the fact that they will need to spend at least one night in the vet surgery – possibly longer if surgery is needed.

how long after heartworm treatment can dog be active?

There will also be a period of convalescence after the fact, possibly one that involves the purchasing of medications that will help your canine chum overcome any side effects of their treatment. That’s a lot of money and a lot of discomfort for your dog. Surely the idea of prevention is much more appealing?

Will My Pet Insurance Cover the Cost of Heartworm Treatment?

This depends on your contract with your insurer, so read the small print very carefully before deciding upon which policy to take out.

Some policies will cover the cost of preventative measures against heartworm, others will pay for the surgical or medical intervention required after the fact, and others still will play no part at all in heartworm.

Where pet insurance is concerned, you always get what you pay for. Pay close attention to what is offered by your insurer (and consider the price of the excess alongside your monthly payments), and make an informed choice if you consider your dog to be at risk of contracting this condition.

How to Care for a Dog After Heartworm Treatment

The most important thing to know is that your dog will need to be watched regularly, so keep in constant contact with your vet during the recovery period and be prepared to leap into action if you spot any untoward symptoms as part of your canine’s recovery.

It’s also important to know that, after a dog has undergone heartworm treatment, they’ll have to take things very, very easy. This means that you’ll have to make your dog comfortable and give them space.

If you haven’t previously done so, check out the guide on to how to crate train a dog that barks and whines. The same advice applies here – giving your dog somewhere they feel safe and relaxed is hugely important.

Your dog will also need to rest, so make sure that their crate (or open bed if that’s the approach that you decide to take) is somewhere away from the rest of your family. If your dog is under the weather, young children may want to cheer them up by playing.

Unfortunately, Fido will not be able to undertake exercise while recovering from heartworm treatment, so remove the temptation from his or her path. Plenty of love, plenty of food and water, and plenty of sleep – that’s the only way that your dog will make a full recovery.

How Long Will It Take for a Dog to Be Active Following Treatment?

It will take around six weeks – four at the absolute least – before your dog can get back to being their old running, jumping and playing selves.

It’s hugely important that your canine companion is given enough time to recover fully from their ordeal, as excessive exercise will aggravate their problems and potentially undo all the work of their invasive and expensive treatments.