Heartworm disease is a condition that affects dogs and is caused by the parasitic worm Dirofilaria immitis, writes Dr Rose Hasegawa, medical director Te Are Manu Vet Clinic.

It is spread through mosquito bites and can affect the heart, lungs and blood vessels. While heartworm disease can be serious, the good news is that it can preventable and treatable with veterinary care.

Heartworm disease spreads when a mosquito bites an infected dog and picks up microscopic larvae known as microfilariae. Over the next couple of weeks, these larvae mature inside the mosquito. When the mosquito bites another dog, the larvae enter the bloodstream and gradually move to the heart and lungs, where they continue to grow. Heartworms take several months to develop into adults, and they can live for years.

Many dogs with heartworm disease do not show signs of infection for months or even years. In the early stages, they may appear completely healthy. This is why blood testing is important – it helps detect heartworms before they can cause problems.

When symptoms do develop, they may include a mild cough, decreased energy levels, or reluctance to exercise. In later stages, more noticeable signs such as difficulty breathing and weight loss may appear. The earlier heartworms are detected, the easier they are to manage.

The best way to prevent heartworm disease is through regular veterinary care. One of the most convenient options is an annual heartworm preventive injection, which offers continuous protection without the need for monthly doses.

If your dog has not been tested for heartworm disease, consider booking an appointment with the vets are Te Are Manu. The first steps of heartworm testing and treatment starts with putting them on prevention injection, followed by a blood test four months later. A heartworm test is a simple procedure that provides valuable information. If your dog tests positive, your vet will discuss potential next steps with you.

If a dog tests positive for heartworm disease, treatment is available following the American Heartworm Society’s guidelines. The recommended protocol includes a series of injections with a medication called melarsomine, which eliminates adult heartworms. Prior to the injections, the vet will prescribe antibiotics and anti-inflammatory medications to reduce complications. Strict rest and limited activity are crucial throughout the treatment process to prevent complications as the worms break down and are cleared from the body.

While treatment can be costly and requires careful management, early detection and prevention remain the best ways to protect dogs from this condition.