Heartworm in dogs (Dirofilariasis): Symptoms, treatment and prevention

heartworm disease or heartworm disease is a very serious disease that occurs as a result of a mosquito bite even infected with the worm Dirofilaria immitis. The insect deposits larvae, which then migrate to the dog’s pulmonary arteries before developing. It is important to act very quickly in order to hope to avoid the death of the animal. The disease progresses slowly when the worms are present in his body, but its outcome is often fatal if treatment is delayed.

How is this pathology characterized? What are the clinical signs to be aware of? How to treat it? Is heartworm disease possible? Let’s take a look at this case.

What is heartworm disease in dogs or dirofilariasis?

Dirofilariasis or heartworm can affect dogs and cats. It is a non-communicable heart disease that is transmitted to the animal by the bite of a mosquito infected with the worm. Dirofilaria immitis. If this pathology is essentially observed in the places where these mosquitoes are present, i.e. in the tropical and subtropical zones, seasonal peaks can be observed in the northern hemisphere, especially from March to October around the Mediterranean and in summer further north . of the country.

Shortly after the bite, the worms’ larvae, which are deposited on the dog’s skin, migrate to its heart. They settle in the pulmonary arteries, which are the arteries that start from the heart, sometimes even in the right part of the heart. They live there for several years and their presence can cause the death of the animal. In fact, if the invasion is rapid, the development of the disease is slow. On the other hand, it has serious consequences and can lead to heart failure and sudden death.

ormen Dirofilaria immitis can contaminate several species of domestic and wild carnivores, such as dogs, cats, ferrets, foxes and wolves. When the worms in the dog’s body reach adulthood, they give birth to new larvae, called microfilariae. These larvae enter the bloodstream and can thus contaminate the mosquito, which feeds on the blood of its victim. As soon as it bites another animal again, it can transmit the disease to it.

What are the symptoms of heartworm disease in dogs or dirofilariasis?

Heartworm disease can be very serious for the dog and lead to its death. It is therefore imperative to be aware of the symptoms that it is likely to cause.

These clinical signs develop in accordance with the progression of the disease. Remember that if the invasion of the larvae is very rapid after the bite of the infected mosquito, the development of the pathology is slow then.

Symptoms in the first stage of the disease

Initially, you may observe one or more of the following clinical signs in your dog:

  • persistent fatigue and lack of drive;
  • cough;
  • significant weight loss;
  • ischemic muscle myopathy, which corresponds to a weakening of the muscles;
  • skin disorders;
  • pulmonary effusion;
  • renal failure accompanied by an increase in creatinine and urea;
  • eye disorders, less common but possible;
  • syncope.

Symptoms in the second stage of the disease

As heartworm disease progresses and worsens, the animal may show the following clinical signs:

  • general weakness;
  • anorexia;
  • lethargy;
  • jaundice or jaundice;
  • dark colored urine;
  • a neurological syndrome that can cause depression, mobility impairment, coma, etc. ;
  • cava syndrome (or intravascular hemolytic syndrome), which corresponds to a very serious complication of the pathology in case of massive invasion. The animal then presents with ventricular tachycardia, which increases the risk of cardiac arrest.

The more worms there are, the more severe the symptoms of the dog. In the slightest doubt, it is important to consult the vet as soon as possible, because the faster the care of the dog, the greater the chances of saving the animal. Ideally, it is necessary to act before the larvae reach adulthood, because then their reproduction accelerates and the invasion becomes too important. They invade the heart muscle, destroy red blood cells, inflame and clog the pulmonary arteries.

What is the treatment for heartworm disease in dogs or dirofilariasis?

What is the diagnosis of canine dirofilariasis?

To confirm the pathology, the veterinarian can perform several additional examinations:

  • serology;
  • a blood count and blood count to estimate the extent of the inflammation;
  • the search for biochemical parameters to identify possible kidney damage;
  • echocardiography or ultrasound of the heart.

What is the treatment for heartworm disease in dogs?

Once heartworm disease has been confirmed in dogs, it is important to initiate prompt treatment to relieve the animal as soon as possible. A double action is essential to:

  • destroy the larvae (microfilariae) through treatments in the form of antiparasitic macrocyclic lactones, by oral administration or injection;
  • destroy adult worms (filariae) through intramuscular injections of Melanasarmin.

It should be noted that the administration of these treatments requires monitoring of the animal for a minimum period of 12 hours. These are actually powerful and risky treatments because the destruction of the filariae and microfilariae can cause a reaction in the dog, such as cardiovascular failure.

In addition, it is sometimes possible in some countries to perform a surgical procedure when the animal has a cava syndrome because the invasion of the heart is massive. It is a long, expensive and risky operation, called “last chance intervention”, performed under fluoroscopy. This process allows the guidance of a pair of forceps inserted into the jugular vein to remove the worms present in the heart.

Finally, it is important to emphasize that the fastest treatment is crucial for the dog’s survival. Administering a treatment that claims to be effective may not be enough to save the dog’s life if given too late. Furthermore, if the dog succeeds in surviving, the comorbidities are still significant in connection with late treatment.

Can heartworm disease in dogs or dirofilariasis be prevented?

It is not always possible to prevent heartworm in dogs. Nevertheless, to protect your animal, it is preferable to observe the following precautions:

  • Remember to regularly give your dog the necessary external dewormers and antiparasits (flea and tick repellents).
  • Avoid letting your dog walk alone as it may encounter an infected animal.
  • Keep mosquitoes away from your home as much as possible, by equipping yourself with mosquito nets or by emptying containers of stagnant water (plant bowls, watering cans, etc.).

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