What is Heartworm?

Heartworm is a parasitic adult worm that lives in the heart, lungs and blood vessels of an infected animal. Heartworm is spread via the bite of a mosquito. During the hot months of late spring, summer and early fall, the mosquito produces heartworm eggs and can transmit these eggs into the dog’s bloodstream through a small bite wound.  In a dog, it takes around 6 months for the eggs to fully mature into adult heartworms and begin to release their eggs called microfilariae into the dog’s blood stream.

What can I do?

By visiting your veterinarian every year and performing a blood test to determine the presence of microfilariae, you can help save your dog’s life by early detection and treatment. If negative for the presence of microfilariae, we can begin your dog on a heartworm preventive that is appropriate to their weight and lifestyle.

Why test for heartworm every year if my dog has tested negative the year before and began a preventive?

Recall that heartworm takes around 6 months to grow and mature into adults before they will begin to mate and release their offspring (microfilariae). Therefore, even though your dog was tested negative and started on a heartworm preventive they could have been bitten before the start of the first monthly dose or have been bitten when the 6 months of prevention was complete (if you treat the dog from June to November). Also consider that the risk of contracting heartworm can increase because of missed doses, late doses, changes of preventive or traveling to countries with high incidences of heartworm.

Starting a dog on a preventive without a blood test to confirm the absence of microfilariae can be harmful or deadly! It is important to note that administering a preventive to a heartworm positive dog is not an appropriate method to kill heartworms and microfilariae safely and successfully. If a microfilariae positive dog is administered a preventive, this could potentially cause the microfilariae to die and remain floating in the bloodstream, triggering a shock like reaction and possibly death.

How can I prevent heartworm?

You can begin your yearly heartworm blood test on April 15th starting with a blood test (if you are considering a six month heartworm prevention from June to November). If your blood test comes back negative for heartworm, you can choose from many different heartworm preventives to satisfy the needs of you and your dog. The products are all FDA approved and require a prescription from your veterinarian. Most products are given monthly and come in tablets or chewable formats or as a topical to apply on the back of the animal. Heartworm preventive also contain ingredients that can help protect your dog from other internal parasites such as roundworm, hookworm and other common external parasites such as fleas, ticks and ear mites.