Heartworm Prevention

We recommend starting your puppy or kitten on heartworm preventative as soon as possible, or as young as 8-9 weeks of age.   Here in Louisiana, heartworm-carrying mosquitoes are active year-round, so we recommend year-round prevention.  Starting late or skipping doses may cause your pet to become infected with heartworms. To elaborate, let’s discuss how pets contract heartworms.  Mosquitoes, carrying microscopic baby heartworms (larvae), bite your dog. These larvae immediately start their journey from the skin to the heart through the smallest blood vessels in the body.   Monthly heartworm preventives kill the  larvae that your pet has accumulated over the previous month, so they are actually monthly heartworm dewormers.  By skipping or forgetting to give the usual dose for a month here or there, or 2-3 months in a row, may result in 2-3 month -old or older larvae. Preventatives only kill one-month-old larvae. This means your dog is now infected.  Your best course of action is to immediately restart the monthly preventative to prevent more larvae from infecting your pet, and consult  with our doctors on the next course of action, and when to have the next heartworm test performed.

Should your dog test positive for heartworms, you have options for treatment.  We follow the recommendations published by the American Heartworm Society.   The recommended treatment is 2-3 injections of  melarsamine, which kills the adult worms, given in divided doses over 1-2 months. This  treatment option is ideal because the worms are killed and removed the most rapidly, thereby preventing further damage to the inside of the heart and lungs.  For dogs that cannot receive the injections, treatment by  prevention of further infection is the only other method available. This is referred to as the “Slow Kill” method.  The existing adult worms are allowed to live out their lifespan, but more worms are prevented from infecting the pet by starting a strict preventative program.  Heartworm disease can be devastating to the pet’s health, but  if we can diagnose and treat the disease in the early stages, the infection can leave virtually no lasting symptoms. The key to this disease is prevention, prevention, prevention.

Cats are infected with heartworm larvae by biting mosquitoes just as frequently as dogs are.    However, in cats, the worms rarely mature to adults in the heart.   They develop all the way to the lungs, causing damage there, but the cat’s immune system usually causes worm death at this stage.  A cat can be infected and reinfected it’s whole life, never having an adult worm,and always testing negative.  This is why we used to think that cats didn’t get heartworms, because the test that we use in dogs detects adults only, not immature worms. As rare as adult worms are, it does occur, and a single adult heartworm can cause sudden death. There is no approved treatment for heartworms in the cat.  The only way we can prevent heartworm-related death or lung disease in the cat is by giving her/him monthly heartworm preventative, just like dogs.  The good news is that heartworm preventatives are easy to use and effective.  

 Get more info at the best  source available–the American Heartworm Society website. Arm yourself with knowledge!!

www.heartwormsociety.org/pet-owner-resources/heartworm-basics