One of the most frustrating aspects of my job is when I fail to convince a dog owner of the importance of heartworm screening and heartworm prevention. The clients give me all of the same rationalizations for choosing not to engage in heartworm parasite screening and prevention. They are listed below with my typical rebuttals in italics.
My dog does not spend much time outside.
All it takes if one mosquito bite. If mosquitoes are biting you, they are biting your dog and possibly injecting infective heartworm larvae into their blood stream.
I don’t like giving my dogs chemicals and would rather take my chances.
Heartworm preventive medications are micro-doses of macrocyclic lactones, compounds derived from naturally occurring soil bacteria that kill juvenile forms of certain types of worms and are virtually harmless to mammals.
I will just put my dog on heartworm prevention if he gets heartworm.
By the time the heartworm surpasses the infective stage of larval development, heartworm prevention is not effective in killing the more advanced stages. Killing more developed larval stages and adult forms of heartworm will require treatment with three painful injections of an arsenic based compound that is far more toxic than virtually harmless heartworm preventive products. Heartworm treatment will also cost the equivalent of more than 10 years worth of heartworm prevention medication.
Sometimes hearts and minds are changed with these conversations and owners change their minds and understand the importance of heartworm prevention. Sometimes they are not and I am left feeling like I am banging my head against a wall with an innocent dog leaving my office at risk of contracting a debilitating and deadly disease that is so safely, easily, and effectively prevented.
So the heartworm positive cases inevitably continue to come through our door, about 2-3 per month, in my average volume clinic only a mere tiny fraction of positive cases nation wide. We have to run blood work and take chest x-rays to determine infected dogs’ state of general and heart health prior treatment. If they have heart enlargement evident on chest x-rays or present with a heart murmur, we recommend cardiac ultrasound to evaluate the heart chambers, heart contractility, and heart efficiency prior to treatment.
Ultrasound also will show us if there is a heavy worm load within the heart. In cases of heavy loads of adult heartworms, a mass chemical kill of the worms could be dangerous to the canine patient. In these cases, we often recommend a heart catherization procedure to directly extract as many worms as possible with small forceps prior to treatment with the arsenic based melarsamine injections.
Heartworm positive dogs are also generally treated with one month of a steroid and the antibiotic doxycyline prior to treatment to reduce inflammation within the heart and blood vessels and protect the patient from a deadly blood born infection following a mass worm kill off. It is expensive and invasive and so unnecessary when the feeding of a harmless heartworm prevention chew treat once a month so effectively prevents all of this madness.
Treating the aftermath time and again of dog owners refusing to heed my advice to administer heartworm prevention in their dog, every time a dog owner refuses to screen for heartworm disease and administer prevention, it never fails to leave me disheartened even after nearly 16 years of practice. I implore anyone reading this article to please not dismiss the potentially tragic consequences of canine heartworm disease and choose to learn the hard way when a dog is infected and sick. Choose instead to prevent!
Dr. Roger Welton is a practicing veterinarian and well regarded media personality throughout a number of subjects and platforms. In addition to being passionate about integrative veterinary medicine for which he is a nationally renowned expert, Dr. Welton was also an accomplished college lacrosse player and remains to this day very involved in the sport. He is president of Maybeck Animal Hospital , runs the successful veterinary/animal health blogs Web-DVM and Dr. Roger’s Holistic Veterinary Care, and fulfills his passion for lacrosse through his lacrosse and sport blog, The Creator’s Game.