Heartworm Disease and Your Dog

As responsible dog parents we go to great lengths to ensure that our fur babies receive proper nutrition, exercise and regular veterinary care. However, there's one hidden danger that often goes unnoticed until it's too late: heartworm disease. 

Heartworm disease is a serious and potentially fatal condition that is caused by the transmission of parasitic worms (known as Dirofilaria immitis), primarily through the bite of infected mosquitoes. These worms can invade the heart, lungs and blood vessels, leading to severe health complications and, in some cases, even death.

By prioritising heartworm prevention and staying vigilant, we can ensure that our canine companions live long, happy and heartworm-free lives. So, how can we protect our pets from this invisible threat?

How Do Dogs Get Heartworm Disease?

Transmission and Life Cycle of Heartworms

Heartworms have a complex life cycle that involves multiple stages and requires a mosquito as an intermediate host. The life cycle begins when an infected animal, usually a dog, has adult heartworms present in its bloodstream. When a mosquito bites an infected animal it ingests microscopic heartworm larvae, called microfilariae, along with its blood meal.

When the infected mosquito bites another susceptible animal, such as a dog, it injects these infective larvae into the animal's bloodstream. The larvae then migrate to the heart and adjacent blood vessels, where they continue to grow into adult worms over several months.

Once mature, adult heartworms can reach lengths of up 30 cm and can live for several years within the infected animal. The adult female worms produce microfilariae, which circulate in the bloodstream, completing the life cycle when another mosquito bites and ingests them.

Where is Heartworm Disease Found?

Heartworm disease is found in many parts of the world but in general, heartworm infection is more common in warmer and humid regions where mosquitoes thrive.

(It's important to note that heartworm disease can occur in areas outside the typical high-prevalence regions, especially with the ease of travel and transportation of infected animals. Therefore, it's crucial to prioritise heartworm prevention regardless of where you live.)

Symptoms and Diagnosis

Recognising the early signs and symptoms of heartworm disease is crucial for early detection and prompt treatment, however, it's important to note that symptoms may not always be evident in the early stages of the disease. As the infection progresses, the following signs may become more noticeable:

1. Mild, persistent cough

2. Reduced exercise tolerance

3. Weight loss and decreased appetite

4. Lethargy and weakness

5. Difficulty breathing

It's important to remember that these symptoms can be associated with various other health conditions, so a proper veterinary examination and diagnostic testing are necessary for accurate diagnosis.

Early Detection

Our vets use a combination of diagnostic tests and procedures to confirm the presence of heartworms, including:

1. Blood tests which can detect the presence of heartworm antigens or microfilariae in your dog's bloodstream. Antigen tests can detect adult female heartworms, while microfilariae tests detect the presence of immature larvae.

2. Imaging techniques such as x-rays (radiographs) and ultrasound examinations can provide visual confirmation of heartworm infection. 

IMPORTANT: Heartworm disease has a period called the "silent phase" when diagnostic tests may not detect the infection. This is why annual heartworm testing and preventive measures are strongly recommended, even if your dog has been tested negative in the past.

How Can I Stop My Dog From Getting Heartworm Disease?

When it comes to heartworm disease, prevention is always better than treatment. Heartworm treatment can be risky, especially for dogs with advanced stages of the disease. The sudden death of adult worms can cause severe inflammatory reactions and potentially life-threatening complications. Even after successful treatment, some dogs may experience long-term health issues and reduced quality of life.

Reduce Your Dog’s Exposure to Mosquitoes

• Limit your dog's outdoor activities during peak exposure times (dawn and dusk) to reduce the risk of mosquito bites.

• Eliminate standing water. Regularly empty and clean any containers, bird baths or other sources of stagnant water in your yard to minimise mosquito breeding sites.

• Apply veterinarian-approved mosquito repellents or insecticides specifically designed for dogs.

• Use mosquito nets or outdoor enclosures to create a mosquito-free area where your dog can play and relax.

Get Your Dog Tested Regularly

Regular heartworm testing is crucial, even if your dog is on preventive medication. Annual testing ensures that any potential infection is detected early and appropriate measures are taken.

Implement Year-Round Prevention

Heartworm disease prevention should be a year-round commitment and consistency is key.

Regular veterinary check-ups allow our vets to monitor your dog's overall health and assess the effectiveness of the preventive measures.

Preventive options include:

1. Oral monthly preventives which come in chewable tablet form, making administration easy. Some products provide protection against other intestinal parasites as well.

2. Topical preventives such as spot-ons are applied to your dog's skin between the shoulder blades. They are easy to use and provide protection against a range of parasites, including heartworms, fleas, ticks and some types of mites.

3. Injectable preventives offer long-lasting protection against heartworm disease. They typically provide coverage for up to one year, eliminating the need for monthly administration and reducing the chances of missed doses.

Early detection, accurate diagnosis and timely treatment are crucial in managing heartworm disease effectively and improving the chances of a successful outcome for your beloved canine companion.

Has your dog had a heartworm test recently? If not, we strongly recommend that you book in for a test. Call our friendly reception team today on (03) 9568 2211.