How Does Heartworm Disease Affect Dogs?

Is your dog lethargic? It could be due to heartworm disease. Learn how heartworm disease affect dogs

Just like humans, our pet dogs are prone to contracting multiple diseases. Heartworm is a common and severe disease that affects dogs and other pet animals. It is caused by a blood-borne parasite called a foot-long worm, heartworm, or  Dirofilaria immitis. 

They enter the pet’s body through the bite of an infected mosquito and affect critical internal organs such as the heart, lungs, and associated blood vessels. 

Heartworm disease is also called dirofilariasis. When a dog gets bitten by a carrier mosquito, the parasite gets transferred into the dog’s system. Female adult heartworms are usually 6-14” long and one-eighth of an inch wide. Female heartworms are usually twice the size of male worms. 

Heartworms reproduce rapidly inside the host’s body. On average, the female heartworm has a life span of five years during which she can give birth to millions of heartworms. The offspring heartworms are called microfilaria and live inside the blood vessels of their host. 

The Lifecycle of a Heartworm Disease

• The lifecycle of heartworm disease is similar to malaria and other diseases that are carried by mosquitos. It starts when a mosquito bites an infected dog and begins to carry the microfilariae of heartworm. When the infected mosquito bites a healthy dog, it transfers the microfilariae into its body. The dog now becomes the new host of heartworm.

If provided with suitable conditions, the microfilariae develop into infection-causing larvae inside the mosquito’s body over the next two weeks. Once the larvae become adult heartworms, they start to impact the heart and lungs of the infected dog. 

• The microfilariae cannot develop into infective larvae inside the mosquito’s body. A mosquito only acts as a carrier. The microfilariae become infective larvae only inside their host’s body which in most cases is a dog. When a dog gets infected, the larvae develop into full-grown adult heartworms in 5-7 months. 

Mating between male and female heartworms occurs inside the dog’s body and multiple offsprings are produced. Adult heartworms look like long and intermingled strands of spaghetti. The number of worms living inside a host is defined as a worm burden. On average, the worm burden is 15 per dog.

Symptoms of Heartworm Disease

Heartworm is a dangerous and sometimes fatal disease. It is important to know the signs and symptoms of heartworm disease to take timely action. The impact caused by heartworm disease and the symptoms displayed by the dog depends on the following factors:

• The worm burden i.e. the no. of worms that have infected the dog
• Duration of infection
• Strength of the dog’s immune system  

Based on the severity of the disease, the symptoms caused by heartworm disease can be categorized into the following classes:

• Class 1: Low severity of the disease. If a dog is young and active, he will display no symptoms of the disease or very mild symptoms like an occasional cough.
• Class 2: Mild to moderate severity. The symptoms displayed include fatigue after physical activity and off and on bouts of cough.
• Class 3: Infected dogs that fall into this category display severe symptoms of the disease such as continuous cough, lethargy, and a ghastly appearance. The parasite has damaged their lungs and hearts. As a result, the infected dog has breathing issues. 
• Class 4: This class of infected dogs suffers from an increased worm burden. The no. of worms inhabiting the hosts’ body is so large that they form a massive blockage to the heart. This condition is called caval syndrome. Caval syndrome presents a life-threatening situation and can only be treated by surgery.

If you fear your dog is suffering from Heartworm disease, we recommend you to try  Simparica Trio. Its 3-in-1 formula is very effective against treating fleas, ticks, and heartworm disease. For more information, contact Autumn Trails Veterinary Center located in Charlottesville, VA.