The Heart of the Matter


I see this time and time again.  The sick dog that comes into the clinic; not eating, lethargic and losing weight over the last month.  My first question to the client, after reviewing history,

“Is this dog on any preventative medicine? Like heartworm preventative or flea/tick preventative?”

“No. Should it be?,” says the client.

Instantly my heart sinks because I almost always know the diagnosis.
After giving the dog a thorough exam I go over diagnostics that we should perform.  First, let’s do a heartworm test and a fecal.  Second, let’s do some bloodwork to check liver, kidney, electrolytes, etc.

I carefully draw blood from the very sick dog and set up my heartworm test. I also apply a drop of blood to a slide and look at it under the microscope.  Again, my heart sinks.  There are tiny microfilaria (babies from the adult heartworms) swimming around in this dog’s blood.  I also ran blood work and sadly this dog was in kidney and liver failure.  Because this dog was not on preventative for heartworms and probably has had heartworms for several years, his organs were now having complications because of it.

What makes me sad is that this is a very preventable disease.  At the clinic I have seen over 25 dogs test positive for heartworms in the last four months.  One dog is too many, 25 is alarming!
Let’s talk about heartworms….

So what are heartworms?
Heartworms are bad parasites that can kill your dog (and cat).

Adult heartworms can be found in any infected canine (dog, coyote, wolf, etc.).  These adult heartworms have baby heartworms called microfilaria that swim around in your dog’s blood.  When a mosquito bites an infected dog they sip up blood that has microfilaria.  The microfilaria develops into a mature larvae in about 10-14 days (Infectious stage).  The mosquito, that now has mature larvae, bites another dog and releases these larvae into the healthy dog.  If your dog is on a monthly preventative it will kill the larvae before it can develop into a mean adult heartworm. If your dog isn’t on a preventative this larvae can develop into a mature adult heartworm in six months that will now produce microfilaria.

Adult heartworms can lead to multiple issues. Heartworms live in the heart and can lead to heart failure. This is why it is so important to keep your dog on preventative medicine.

My dog isn’t on preventative. What should I do?

  1. Start by taking your dog to a veterinarian.  
  2. Your veterinarian will need to do a wellness exam and a heartworm test on your dog.

Why can’t I just start them on heartworm preventative?

  1. Heartworm preventative is a prescription. Your dog will need an exam every year to renew or start on preventative.
  2. Starting on preventative without testing first could kill your dog. If your dog has heartworms they can have a reaction and die. No bueno.

Should I get my pet tested every year if they have been on preventative year round?

  1. It is recommended that your dog get tested every year to make sure the preventative is working
  2. You can decline the test only if your dog has been on preventative every month without skipping.  But the patient still has to have an exam every year.  Again, it is recommended testing every year just to be on the safe side.

What product should I use?
There are a lot of really great products on the market, my personal favorite is Heartgard and I pair that with Nexard (flea/tick preventative).

There are too many heartworm preventative options to name them all, so ask your veterinarian what is best for your pet.

Can you treat heartworms?

  1. Yes. But there are a lot of factors that go into treatment.
  2. It can be very expensive.
  3. The length of infection and severity of the disease can influence the outcome of treatment.
  4. It is better to prevent than treat. AND a whole lot cheaper ☺

The outcome of severe heartworm disease is not pretty. Unfortunately, I see too many of these cases every year.  As for the dog that I diagnosed with heartworms, his case was so severe that we were not able to treat and the owners opted to put him down.  This dog was only nine years old.  It always breaks my heart. 

Dr. Hartfield1 Comment