Canine Filariasis: Also Known As Heartworm in Dogs

Heartworm is a common parasite that affects dogs. it's important to understand how to detect and treat this potentially serious illness.
Canine Filariasis: Also Known As Heartworm in Dogs

Last update: 06 March, 2019

Canine filariasis is most popularly known as heartworm in dogs. This is a common condition in dogs that live in warm or humid climates, or near rivers or other bodies of water. If you don’t treat it in time, it can be fatal for dogs. That’s why it’s important for you to know how to detect it and, above all, how to prevent it.

What is canine filariasis?

Canine filariasis is a parasitic disease that is caused by heartworm in dogs (Dirofilaria Immitis) in the right ventricle of the heart and in the blood and lung vessels of the dog. This then obstructs normal blood flow.

These worms grow and reproduce inside the dog, living between 5 and 7 years there. The parasites feed on nutrients they get from the animal’s blood.

In serious infections, dogs can have more than 100 worms. These can reach between 6 to 12 inches long.

Heartworm in dogs can be fatal.

Canine filariasis or heartworm disease is a condition that, if not treated quickly, can be fatal. Learn how to recognize it and prevent it in your dog.

How heartworm in dogs spreads

Canine filariasis is transmitted to dogs via mosquito bites from the genus Culex, Aedes, or Anopheles.

When one of these insects bites an infected dog, the dog absorbs the larva. This then becomes an immature worm inside the mosquito. This process takes around three weeks.

Then, when the infected mosquito bites a healthy dog, it introduces the worm. This causes the dog to become infected.

Signs that your dog may have filariasis

Filariasis is a disease that doesn’t show any signs until it is very advanced. In serious cases, you may see the following symptoms:

  • Respiratory difficulties
  • Accelerated heart rate
  • Chronic cough
  • Fatigue
  • Intolerance to exercise (due to a weakened heart)
  • Bleeding from the mouth and nose
  • Lack of appetite
  • Weight loss
  • Apathy

How filariasis is treated in dogs

To know if a dog is suffering from canine filariasis, a veterinarian will do a blood test. If the results show that the dog has heartworm, there are several treatments, according to how advanced the disease is, and the animal’s condition.

You can treat worms in a dog’s heart with injections. In addition, you can use antiparasitic tablets to remove the larvae.

On the other hand, there is a risk of blood clots forming. This is because of the blockages that dead parasites cause in the blood vessels. Due to this, it’s essential that the dog rests during treatment. Walking and physical activity should be reduced.

Sometimes it may be necessary for the animal to stay in a veterinary clinic to ensure immobility. This also helps veterinarians better control their treatment.

However, in advanced cases where the dog has a severe infection, the dog may need surgery to remove them.

How to prevent heartworm in dogs

A dog eating a treat.

If the treatment is successful, your vet may recommend vitamins and a specific diet to help your dog in her recovery. In addition, you need to make sure your pet doesn’t become infected again.

The way to prevent heartworm in dogs is to give healthy dogs the same medication used to get rid of immature larvae and worms in infected dogs. You should give this medicine once a month, according to your vet’s recommendations.

Another method of preventing heartworm in dogs is through a treatment via droppers, which you need to apply every 30 days. In addition, you can give your dog an injection once a year.

Don’t forget to consult an animal health professional to get rid of any doubts you have about heartworm disease and to determine the best form of prevention for your pet.


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This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.