Heartworm in puppies was something that was recently discussed in the Reddit dog group I belong to, vets and puppy parents whose puppies have had it enlightened us a lot about it.
I decided to make a blog post about it and help puppy parents whose puppies might have heartworm disease.
What is heartworm in puppies?
Heartworm disease in puppies is a critical disease and it could be fatal, leading to severe lung disease, heart failure, damage to other organs, and death.
Heartworm in puppies are very long parasitic worms called Dirofilaria immitis, they live in the hearts, lungs, and blood vessels causing a lot of damage.
Your puppy is a natural host for heartworms, meaning that heartworms in your puppy mature into adults, mate, and produce offspring in your puppy.
The number of heartworms in your puppy can increase if not treated immediately.
Cats, ferrets, wolves, coyotes, foxes, sea lions, and in rare cases also humans can be affected by heartworms.
The parasitic worms are called “heartworms” because the heart, lungs, and associated blood vessels are where the adults live.
Adult heartworms look like strands of cooked spaghetti, the females are usually the longest reaching about 10 to 12 inches in length and the males are usually about 4 to 6 inches.
The average worm burden in dogs is about 14 to 16 worms, but it could be up to 250 worms.
A worm burden is the number of worms living inside an infected dog.
Causes of heartworm in puppies
Heartworm is spread to puppies by mosquitos which are the intermediate host, this means that the heartworms live inside a mosquito for a short transition period to become able to cause heartworm disease.
Lifecycle of heartworm in puppies
In an infected dog, fox, coyote, or wolf, adult female heartworms release their offspring which are microscopic baby worms called microfilariae into their bloodstream.
When an infected animal is bitten by a mosquito, it takes along the baby worms in the blood and it would take 10 to 14 days for the bat worms to develop and mature to a stage in which they can be infective.
When the infected mosquito bites another puppy, the infective larvae are spread through the bite wound.
It takes about 6 to 7 months for infective larvae to mature into adult heartworms in newly infected puppies.
Mating occurs between the adult heartworms and the female releases her offspring into the puppy’s bloodstream which completes the lifecycle.
Heartworm can live up to 5 to 7 years in dogs.
Signs and symptoms of heartworm in puppies
In the beginning stages of heartworm disease in puppies, it is very common for there to be no signs or symptoms but as it becomes severe you would start to see symptoms.
The severity of the disease would depend on how long your puppy has been infected, the number of worms living in your puppy, and how your puppy’s body is responding to the presence of the heartworms.
If your puppy has a low worm burden or is recently infected, you may not see any symptoms but if his/her worm burden is high and they have been infected for a long time, you would see symptoms.
From the discussion that went on in the dog Reddit group I talked about, they divided heartworm in puppies into 4 stages when it comes to symptoms.
Stage 1: in this stage, you might not see any symptoms but sometimes there are mild symptoms like occasional cough.
Stage 2: you would notice symptoms like occasional cough, tiredness after moderate activity, and other mild or moderate symptoms.
Stage 3: you would notice more serious symptoms like persistent cough, trouble breathing, unhealthy appearance, tiredness after little activities, and signs of heart failure.
Stage 4: there would be a heavy lot of worms to the extent that blood flowing back would be physically blocked by the heartworms and it is called caval syndrome.
This stage could end your puppy’s life if the heartworms are not quickly surgically removed and surgery is the only option at that point.
Most dogs with caval syndrome die even with the surgery.
Diagnosis of heartworm in puppies
Your vet would most likely carry out one or more blood tests to diagnose heartworm disease.
One of the tests your vet might carry out on your pup’s blood is an antigen test.
An antigen test detects proteins that are produced by female adult heartworms in your puppy’s bloodstream.
This test would only work if it has been 5 months or more after your puppy has been bitten because that is the earliest that the heartworm protein can be detected in your pup’s bloodstream.
The other test detects the baby worms (microfilariae) that the adult female has released in your puppy’s bloodstream.
It would take 6 months or more after your puppy is bitten by an infected mosquito for the baby worms to be detectable and that’s because it takes about 6 months for the infected larvas to turn to adults and make a lot of babies that can be noticed in the blood.
Knowing about this test, you should know that there is no need to carry out a test on puppies below 7 months.
Treatment of heartworm in puppies
There is an arsenic-containing drug called melarsomine dihydrochloride that is used to kill adult heartworms in dogs, it is FDA-approved.
If your puppy has a stabilized stage 1, stage 2, or stage 3 heartworm disease, he/she may be given melarsomine dihydrochloride by deep injection into the back muscles to treat the heartworm disease.
Some puppy parents also said their puppy was given Advantage Multi for Dogs to get rid of baby worms in their pup’s bloodstream.
Advantage Multi for Dogs is a topical solution that would be applied to your puppy’s skin.
The treatment of heartworm in puppies is expensive because you would have to visit your vet a lot and you would also be doing a lot of injections, x-rays, blood tests, and some hospitalization.
Sometimes treatment can be toxic to the puppy’s body and can cause life-threatening blood clots in the dog’s lungs and other complications.
The thing about roundworm treatment is that most dogs would have gotten to the serious stage and the heartworms have already done damage to the heart, lungs, livers, and blood vessels.
If your puppy has gotten to that stage it may only be able to live a few weeks or months.
In cases where the puppy’s organ is already damaged, the vet would prefer to treat the organ damage than risk the negative effects the drugs used for treatment may have on their body.
Your puppy may experience some complications after treatment which is mostly caused by the decomposed fragments of the worms in their blood vessels that would get reabsorbed in their bodies.
Your puppy should rest and not exercise for a month or two after treatment.
You may also notice a cough in your puppy after treatment, this cough may last for 6 to 9 weeks especially if your puppy was heavily infected, if the cough becomes severe, you should consult your vet.
Prevention of heartworm in puppies
Most people on the Reddit dog group and Facebook groups I belong to say that said that the products they give their puppy for prevention are monthly and are either a topical liquid applied to your pup’s skin or an oral tablet.
There are many products for treating heartworms in puppies that are FDA approved with both chewable and non-chewable tablets
Some heartworm preventions are injections applied under the skin every 6 to 12 months.
FAQs about heartworms in puppies
Can a puppy recover from heartworms?
Yes a puppy can recover from heartworms if diagnosed and treated on time and organ damage has not occurred
What kills heartworms in puppies?
Drugs like melarsomine dihydrochloride and Advantage Multi for Dogs are used to kill heartworms in puppies who have stage 1, stage 2, or stage 3 heartworm disease. I talked about the stages of heartworm disease with symptoms in this post somewhere above.
Can a 2-month-old puppy have heartworms?
Yes, a 2-month-old puppy can have heartworms but it won’t harm the puppy or show any signs yet because it is not fully developed and it takes 6 months for a heartworm to develop after it enters its infectious stage, it would keep growing in the puppy.
What age do puppies have heartworms?
Puppies can have heartworms at any age but it won’t harm the puppy or show any signs yet if it hasn’t stayed up to 6 months because it is not fully developed and it takes 6 months for a heartworm to develop after it enters its infectious stage, it would keep growing in the puppy.
Important information
I am not a vet, everything I talked about in this blog post was based on my personal experience, the experience of people whose dog have had heartworm, and some advice from vets on the Reddit dog group I belong to.
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