What are Heartworms in Dogs?

Heartworm larvae are injected into a dog from the bite of an infected mosquito. Once bitten the larvae make their way through the blood stream and lodge onto the blood vessels of the heart and lungs of the dog. Larvae take 6 to 7 months to develop into adults. These heartworm adults will then reproduce and cause further infection to the dog.
A single host (dog) can have up to 250 heartworms in its body. The worms look spaghetti-like and measure from 4 to 12 inches in length and live up to 7 years.

A dog that suffers from heartworm disease may also suffer from lung disease and heart failure.
Mosquitos can contract the heartworm larvae by sucking the blood of an infected dog and thus spread the disease.

Heartworm Symptoms in a Dog

Symptoms of this disease may be difficult to detect in the early stages of the infestation. Dogs that have been infected for 5 to 6 months or longer may show more clear symptoms of infection.

Blood tests can be done but will only detect signs of infestation after 5 or 6 months when the adult heartworms have produced more microfilariae (immature heartworms).

There are 4 class levels to the disease with symptoms to each class:

• Class 1 – No clear symptoms. The dog may cough a bit.
• Class 2 – A very clear and continuous cough and lower levels of exercise or activeness.
• Class 3 – This is a very advanced stage of the heartworm disease, the dog has difficulty breathing and is coughing a lot. The dog is exhausted after any physical activities. Heart failure is quite prominent at this level.
• Class 4 – This is the highest level of worm infestation. Blood flow to the heart slows down significantly due to the masses of worms in the heart, this will cause the dog to feel very weak and become lethargic. A dog that has reached this class will almost certainly die. Surgery can be performed to try and remove the worms but this often proves unsuccessful.
This class is also referred to as “Caval Syndrome”.

Heartworms Treatment for Dogs

There are two main methods used to treat a dog with heartworms, the first is drugs which can only be used in classes 1, 2 and 3. The drug most commonly used by vets is called Immiticide (FDA APPROVED). Immiticide only kills off the adult worms while larvae and microfilariae still survive.
The larvae will start to reproduce once they reach adulthood so it would be necessary for the vet to inject the dog with the Immiticide once again.

The dead adult heartworms decompose and are gradually expelled though the lungs so it is important to limit any activities that may increase the dogs breathing rate as this may cause the dog to cough up excessive amounts of decay which may result in choking.

The second treatment as mentioned above is the surgical removal of the worms which unfortunately is not very successful and normally ends with the death of the dog.

Natural Remedy

An all-natural product that is highly recommend is VRM2. The combined ingredients which include Black Walnut leaves, Wormseed, Kamala bark, Bethyl Nut and other natural ingredients apparently eliminates the infestation of Heartworm disease in dogs.  


The best way to deal with heartworms is to try to prevent your dog from becoming infested. There are a number of FDA approved drugs which one can get from the local vet, these come in the form of tablets and body lotions. These are all very effective stopping any heartworm disease from developing.

So at the end of the day, prevention is better than cure!

1 comment:

  1. I have tried many heartworm treatment for dogs and only a select few I preferred. It is important to get one you enjoy.



All content in this blog is based purely on research done with the aim of giving helpful advice and information to the owners of dogs.

I am not a qualified vet or dog trainer so please use this site as a reference and not as a professional opinion.