Heartworm

It is that time of year again - heartworm season is upon us!  We have compiled a list of the most frequently asked questions to help keep our clients informed and ensure you are making the best decision for you and your dog!

What is heartworm?
Heartworm is a serious disease that is passed from dog to dog by mosquitos.  When a mosquito infected with heartworm bites another dog, the disease is then transmitted.  In infected dogs, worms grow in the heart and pulmonary arteries causing clogs which prevent normal blood flow and normal function of the valves. 

Is it fatal?

Yes.  If left untreated heartworm is a fatal disease.  Because signs of heartworm are not immediate, the disease can go unnoticed for a number of years until symptoms appear.  This is why it is important to test your dog even if they seem healthy. 

Why does my dog need to be tested if he/she is on the medicine?

Dr. Dunn recommends a test every other year for the following reasons:

1. It is possible the medicine has not been administered properly (missed doses, started before May 1^st or after June 1^st)

2. A dog can be underdosed if they gained weight during the course of the treatment
3. A heartworm preventive dose may be ineffective if the dog had vomiting or diarrhea when the medicine was administered
4. Bad luck – no medicine is 100% effective and occasionally animals with no breaks in the treatment will develop heartworm

It is vital that we know if your dog has heartworm before they show signs of illness.  Dogs can be treated for heartworm but the effectiveness of the treatment is based on how long they have had the disease and how severe the signs are.  We want to diagnose dogs before they show any signs so they can be treated and be perfectly healthy after the treatment is completed.  Based on the typical progression of heartworm disease in our area that means testing every other year.

Can my dog get heartworm from contact with another dog?
No.  Heartworm requires an intermediate host (mosquito) to be transferred from one dog to another.  The exposure of your dog to other dogs has no influence on the chances of your dog contracting heartworm.

What is involved with a heartworm test?
A heartworm test is a blood test.  We will draw 1 mL of blood which will then be sent to a lab and tested for the heartworm antigen.  It is not tested through feces like intestinal parasites.

Why do you recommend my dog be tested between April and June?
Once a dog is bitten by a mosquito infected with heartworm it takes 6 months for a heartworm test to show a positive result.  Therefore, we recommend testing 6 months after their last possible exposure from the previous year.  We recommend testing before June 1^st because it is preferable to have a negative heartworm test result before starting the prevention.

Why is heartworm medicine only given from June to November?
Because heartworm is passed by mosquitos it is only necessary to place dogs on prevention in the warmer months when mosquitos are present.

What kind of medicines do you prescribe to prevent heartworm?
We offer a number of different options to prevent heartworm, here are our 3 most popular methods:

Heartgard: a chewable treat given on the first of every month.  Prevents heartworm only.
Sentinel: a chewable flavour tab given on the first of every month.  Prevents heartworm as well as fleas.
Revolution: a topical treatment applied to the skin on the first of every month.  Prevents heartworm as well as fleas.

If you have any additional questions or need clarification on anything that is discussed here, please give us a call or send us an e-mail!  We are always more than happy to answer questions and discuss which decisions make the most sense for you and your pet!

-Jennifer