Filariasis is a parasitic disease caused by heartworm immitis, also known as “heartworm”. This disease is transmitted through a parasite that is transmitted through hosts, in this case, mosquitoes. Canine filariosis can become highly dangerous, since the adult form of this parasite settles on the right side of the heart, causing considerable damage to a dog’s body. Therefore, if after reading this article you think that your dog could be suffering from filariosis, it will be very important to go to the vet as soon as possible.

Filariasis or heartworm in dogs

Canine filariasis, as mentioned above, is transmitted by a mosquito bite. These worms lodge in a dog’s heart and lungs, with the ability to cause heart failure or even death. The heartworm in dogs is a parasite that exists worldwide, however, its level of infection differs from country to country. Dogs that live outside the home are more likely to get this disease.

When a mosquito with the filariasis parasite bites a dog, the larvae become lodged in the dog’s skin. From there, they undergo several modifications before reaching maturity. Depending on how advanced the dog is in this filarial phase, the disease can be treated by a veterinarian.

In the next stage, the immature worms reach the bloodstream and travel until they are in a heart chamber, such as the right ventricle and pulmonary arteries. Here, they continue their maturation process. When the capacity of the worms is very high, they can travel to the right atrium, including the vena cava and / or the hepatic veins. This infection in the pulmonary arteries can affect the dog’s circulation, obstruct blood flow and form clots.

Blocking or forming blood clots in the heart can cause “pulmonary thromboembolism” and lead to heart failure. Also, if the heartworms are close to the heart valves, they can interfere with the heart’s function. This interference can cause valve disease. The presence of worms in the vena cava or hepatic veins can cause the presence of vena cava syndrome. This syndrome causes liver failure that can occur hand in hand with: jaundice, ascites, or anemia.

Symptoms of filariasis in dogs

The clinical manifestations of filariasis in dogs depend on the size of the dog and the number of worms that are present in this infection. A high number of heartworms are needed for symptoms to be visible. If a dog suffers from a low infection count, heartworm symptoms may not appear.

Canine filariasis symptoms include:

  • Fatigue.
  • Lack of predisposition when it comes to physical activity.
  • Weight loss.
  • Cough.
  • Accelerated breathing.
  • Fainting, especially before exercise.
  • Filariasis in dogs: prognosis

If a dog has any of these symptoms and currently lives in an area where the heartworm is common, this may be a more than possible prognosis. If this is your case, we recommend that you go to the vet as soon as possible for a safe diagnosis.

Also, a vet, in addition to the blood test, is likely to perform an x-ray test. This test will show the possible damage that the parasites have caused to the dog’s heart and lungs. This will allow the vet to understand the severity of the condition.

Heartworm in dogs: treatment

The treatment of filariasis in dogs will depend on the state of the animal and the degree of infection. Once the vet has performed the appropriate tests, they will be able to confirm whether the disease is high or low risk:

  • Low risk: it would correspond to dogs with low presence of parasites and without additional injuries. Normally, this stage has no symptoms and no other diseases. An x-ray will be normal and filariae may not be seen on exams.
  • High risk: they are dogs that have symptoms and there are alterations in their radiographic examination. Parasites are observed and there are concomitant diseases.

In both cases, the treatment must be administered under strict veterinary control. The life cycle time of the filaria must be taken into account. In this treatment, the veterinarian will aim to eliminate the presence of adult filariosis quickly to avoid the risk of thromboembolism. For the same reason, physical activity during this time may be restricted.

There is also a possibility that the worms can be removed by surgery. Months after treatment, a dog should always be retested to ensure that the disease has been completely eliminated.

Can you prevent filariasis or heartworm in dogs?

As we have explained to you, filariasis in dogs can cause serious and fatal consequences and diseases. For these reasons, knowing how to prevent the heartworm in dogs is key. There are several products on the market that can be used to prevent the appearance of worms. These products help prevent larval development. It is very important that you follow your dog’s deworming schedule strictly since he is a puppy.

In addition, it will also be important to consult a veterinarian before choosing an appropriate deworming time for your animal. Ideal prevention would also include mosquito control in your home, as they are hosts to the parasite.

You can also follow other preventive measures, such as: avoiding night walks (especially in summer), since this is when mosquitoes are most frequent. If your dog lives outside, we recommend keeping it indoors during the months of high mosquito presence. Do not forget to deworm your dogs both externally and internally and, if you consider it convenient.

Is filariasis in dogs contagious?

Is heartworm in dogs contagious to other dogs? No: filariasis in dogs needs the intervention of a mosquito to develop. This means that a dog cannot, on its own, infect another animal. The heartworm can only be transmitted by mosquito, from animal to animal, and never from a dog to a human.