Heartworm disease is a serious and potentially fatal disease in pets. It is caused by foot-long worms (heartworms) that live in the heart, lungs, and associated blood vessels of affected pets, causing severe lung disease, heart failure and damage to other organs in the body.   

Dog is a natural host for heartworms, which means that heartworms that live inside the dog mature into adults, mate, and produce offspring. 

If untreated, their numbers can increase, and dogs have been known to harbour several hundred worms in their bodies. Heartworm disease causes lasting damage to the heart, lungs, and arteries, and can affect the dog’s health and quality of life long after the parasites are gone. For this reason, heartworm prevention for dogs is by far the best option, and treatment—when needed—should be administered as early in the course of the disease as possible.     

How is heartworm disease transmitted from one pet to another?  
The mosquito plays an essential role in the heartworm life cycle. Adult female heartworms living in an infected dog, fox, coyote, or wolf produce microscopic baby worms called microfilaria that circulate in the bloodstream. When a mosquito bites and takes a blood meal from an infected animal, it picks up these baby worms. Then, when the infected mosquito bites another dog, cat, or susceptible wild animal, the infective larvae are deposited.     

What are the signs of heartworm disease in dogs?  
In the early stages of the disease, many dogs show few symptoms or no symptoms at all. Signs of heartworm disease may include a mild persistent cough, reluctance to exercise, fatigue after moderate activity, decreased appetite, and weight loss. 

As heartworm disease progresses, pets may develop heart failure and develop an appearance of a swollen belly due to excess fluid in the abdomen. Dogs with large numbers of heartworms can develop a sudden blockages of blood flow out of the heart leading to a life-threatening form of cardiovascular collapse.     

Here is what you should expect if your dog tests positive:  
Restrict exercise- This requirement might be difficult to adhere to, but your dog’s normal physical activities must be restricted as soon as the diagnosis is confirmed, because physical exertion increases the rate at which the heartworms cause damage in the heart and lungs.   

Administer treatment- Once your veterinarian has determined your dog is stable and ready for heartworm treatment, he or she will recommend a treatment protocol involving several steps. 

Dogs with no signs or mild signs of heartworm disease, such as cough or exercise intolerance, have a high success rate with treatment. More severe disease can also be successfully treated, but the possibility of complications is greater.  

Test (and prevent) for success. After treatment is completed, your veterinarian will perform a heartworm test to confirm that all heartworms have been eliminated. To avoid the possibility of your dog contracting heartworm disease again, you will need to administer heartworm prevention year-round for the rest of their life.