Heartworms in Dogs - What You Need to Know

Sadly, I have had a pet die of heartworms and I never really knew just what they were, or where they come from….do you?  I want to share this information with you because I think it is very important.  All dogs and cats should be taking heartworm medication (whether they are pills, shots, etc.) and this post today is going to give you plenty of information on heartworms and what can happen if your dog is infected with them.  If you know any dog owners, please pass this information on to them - it just might save the life of their dog!

*Where do heartworms come from?* 

The parasite Dirofilaria immitis (otherwise known as canine heartworm) develops in mosquitoes and they are carried by many different species.  The heartworms are carried from one mosquito to another and transmit the parasite by biting another uninfected dog.  The larvae carried by the mosquito migrate in the dog’s body for about four months before they reach the dog’s heart.  Following that, the worms develop into adults over the next two to three months.

Heartworms can also be passed on from mother to puppy.  The puppies would become carriers of the infection and would be at risk for a severe reaction when they begin heartworm preventative medication.

Heartworm larvae can also be passed during a blood transfusion.  All dogs involved in the transfusion should be tested for heartworms before the procedure.

*What happens when a dog is infected with heartworms?* 

Heartworms reside in the right heart, pulmonary arteries, and vena cava of dogs.  They are incredibly hard to control because they are spread by mosquitoes (and as you’ll remember - various species of mosquitoes).  The worms cause the most damage to arteries - they can cause the blood vessels to become swelled and scarred - once the diameter of the blood vessels shrink, this causes an increase in pressure on the right side of the heart and will eventually lead to heart failure.

Some dogs will be completely free of any symptoms and this really depends on the number of worms infecting the dog.  There can be anywhere from 1 to 250 heartworms in a dog at one time.  Generally speaking, the higher the number of worms, the greater the risk for complications and the more severe the disease will be.

Some examples of common symptoms include:  coughing, respiratory problems, in more severe cases, the dog may actually cough up blood if enough damage has been done to the blood vessels.  The disease can become incredibly severe if the worms being to die.  The dead worms enter the small arteries in the lungs and the dogs body will react with an inflammatory response and blood clots.

*How do I know if my dog has heartworms?*

There are tests your veterinarian can  perform that will determine if your dog is infected with heartworms.  Thy will draw blood, and examine the sample under a microscope.  An infection of heartworms is fairly easy to detect but only tests done by your veterinarian will be conclusive.

*What are the treatments if my dog has heartworms?*

Heartworm treatments have come a long way, but they can still be incredibly dangerous.  Your dog needs to undergo a pre-treatment evaluation to make sure he is strong enough to complete it.  Any complications (such as blood clots) must be dealt with before the treatment is started.

The most common treatment is the injection of the drug melarsomine.  Dogs will receive two injections 24 hours apart.  This kills off the heartworms and because of the risk after treatment, dogs are to be kept quiet and calm for four weeks following the treatment.

If your dog has a severe case of heartworms, your veterinarian may opt to perform a surgery to remove them.  This is done immediately and your dog can begin other treatments usually within two weeks (after he has recovered from the surgery).

*What can I do to prevent my dog from getting heartworms?*

You should have your dog regularly tested for heartworms by your veterinarian.  Your dog may not show any signs of being infected, so it is only through testing that you can know for sure that your dog is heartworm free!

What I recommend is purchasing through your veterinarian monthly pills such as HeartGuard - these come in tablets or chewables and you must give these to your dog on the same day once per month.  This is probably one of the most effective prevention methods and you can start your puppy on it around six to eight weeks old.

All dogs should be given treatment and be protected from this parasite!  Mosquitoes are everywhere and especially if you live in warmer climates, you need to make sure your pets are safe!

I really hope you enjoyed this post and you now have valuable information on heartworms and their treatments.  Please pass this post on to all the dog owners you know!

Thanks for reading!  As always your participation in comments and discussions are encouraged and greatly appreciated!!