Worms In Dogs In The Heart: Symptoms, Treatment, Prevention Methods

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Worms In Dogs In The Heart: Symptoms, Treatment, Prevention Methods
Worms In Dogs In The Heart: Symptoms, Treatment, Prevention Methods

Video: Worms In Dogs In The Heart: Symptoms, Treatment, Prevention Methods

Отличия серверных жестких дисков от десктопных
Video: Heartworm disease. Treatment, prevention and cost. How to save your pet and money. 2023, February

Page content

  • Description of pathogens
  • Dirofilaria immitis
  • Angiostrongylus vasorum
  • Disease development
  • The main signs of the disease
  • Laboratory confirmation of the diagnosis
  • Diagnosis of cardionematodes
  • Treatment of the disease

    • Pre-treatment
    • Adjunctive therapy
    • Operative treatment
  • Prevention
  • You can defeat parasites!

Heartworms in dogs are nematodes (roundworms), adults of which are found in the pulmonary artery and right chambers of the dog's heart.

There are two types of such helminths:

What to do in such a situation? To get started, we recommend reading this article. This article details the methods of dealing with parasites. We also recommend contacting a specialist. Read the article >>>

Dirofilaria immitis or heartworms (aggl. Heartworm) is a species that belongs to filariae (filamentous worms), or more precisely, dirofilaria. These are the most famous parasites that attack the heart of a dog, causing heartworm disease. They are transmitted through mosquito bites and can also infect humans, cats, ferrets, reptiles, and some other animals.

Angiostrongylus vasorum or French heartworms are helminths that can infect primarily foxes and dogs, causing the disease of canine angistrongylosis (angiostrongylidosis, angiostrongylidosis).

They are also referred to as pulmonary nematodes, since during reproduction the larvae pass through the lungs, damaging them. Transmitted through intermediate hosts such as slugs, snails, frogs, or through food contaminated with the mucus of an infected snail. They are not dangerous for humans.

Heartworms in dogs
Heartworms in dogs

Description of pathogens

The length of adult female dirofilariae (D. immitis), affecting the heart of a dog, reaches 30 cm, males are slightly shorter. In the body of an animal, worms can live for up to 2 years, before that it takes about 6 months for their full development.

These parasites pose a danger to humans, but they do not survive in his body, but are encapsulated in the lungs and die. As a result, granulomas (inflammatory formations) appear, which can be confused with lung cancer in the pictures.

Angiostrongylus vasorum is much smaller - up to 2 cm in length. These are small pinkish worms. Adults can live for 2 years. Previously, it takes 6-10 weeks for their development in the dog's body and getting to places of permanent habitation. They are not dangerous to humans.

Dirofilaria immitis

Heartworms (D. immitis) can be transmitted through the bite of over 70 mosquito species. The insect bites the infected animal and, together with the blood, captures the larvae (microfilariae) floating there. After that, the mosquito plays the role of an intermediate host in which the larvae develop (molt twice) from about 8 days to a month, depending on the ambient temperature.

If it is below 14 ° C, then the parasite freezes and waits for heat. This means that where there are seasonal changes in climate, transmission of these heartworms to a dog or other animal can only occur during the warmer months.

Dirofilaria immitis and Dirofilaria repens
Dirofilaria immitis and Dirofilaria repens

Dirofilaria immitis and Dirofilaria repens

After being bitten by a mosquito, the larvae end up in the subcutaneous tissues of the dog, where they develop. They reach their young adult form within 2-3 months. Then, with the bloodstream, they enter the pulmonary artery, and with a large amount, into the heart. As a result, the period between a mosquito bite and the appearance of fully adult worms in the heart is 6-7 months.

Angiostrongylus vasorum

Larvae of A. vasorum (French heartworms) leave the faeces of a sick animal. They are absorbed by intermediate hosts - molluscs (snails and slugs), inside of which two molts pass. The slugs can then be swallowed by the frog and become a transport (paratenic) host.

Most often, dogs become infected with these heartworms by ingesting a mollusc containing the larva. Also, infection is possible when eating a frog or food that has got snail mucus along with the larva.

Inside the dog, the larvae migrate to the mesenteric lymph nodes, where they molt twice to a young adult form and go to the pulmonary vein and the right chambers of the heart, where they finally grow and begin to multiply.

Angiostrongylus vasorum
Angiostrongylus vasorum

Angiostrongylus vasorum

This takes 6-10 weeks. Viviparous females immediately produce larvae, which are coughed up by the dog, swallowed and exited with feces.

Disease development

Dirofilariasis is a very life-threatening disease in dogs. This is due to the fact that parasites are most often localized in the heart of dogs (in the right atrium), less often in the muscles, eyes and blood vessels. In these organs, they reproduce and feed.

The most likely to become infected with dirofilariasis in late summer, early autumn. It is transmitted from one sick dog to another through mosquito bites. According to statistics, breeds with a smooth coat are more sick with this parasitic disease.

The initial stage of development of parasites is associated with the appearance of larvae - microfilariae. They can be up to several years in the circulatory system of an animal. A mosquito becomes a carrier of parasites after being bitten by an infected dog. During the bite, the larvae, along with the blood, penetrate into his digestive system. During a new bite of a healthy animal, the larvae penetrate through the skin and cells.

Disease development
Disease development

Under the skin, parasites continue to develop for many months. Then they move to the vessels and penetrate the heart. After 7-8 months of being inside the body, the parasites begin to multiply. Their lifespan is 2-3 years. The length of dirofilariae can reach 30 cm. In shape, they resemble thin long threads of light yellow color.

The danger for the dog is not the very vital activity of the parasites, but their death. After death, the body of helminths disintegrates into many parts. They begin to clog the lumen of capillaries and blood vessels. In this case, canine dirofilariasis is often fatal.

The main signs of the disease

First of all, the cardiac and vascular system suffers. Most often, worms are localized in the right atrium or pulmonary artery.

Intertwining with each other, they prevent blood from reaching the heart muscle. As a result, heartworms in dogs lead to the development of a whole range of symptoms.

  • An insufficient supply of oxygen along with the blood leads to cardiac disorders. There is swelling of the limbs and lower jaw.
  • Worms in the heart lead to a decrease in hemoglobin. Symptoms of anemia appear. The dog looks tired, apathetic, sleeps a lot, gets tired quickly.
  • The integrity of the vessels is impaired.
  • Insufficient blood supply to the kidneys and liver leads to disturbances in the functioning of these organs.

Heart worms in dogs can be accompanied by respiratory symptoms.

  • Shortness of breath appears.
  • The dog has difficulty breathing.
  • Disturbed by a dry cough, the intensity of which increases over time.
  • If the lungs are affected, the cough may be sputum. Another characteristic feature is the presence of streaks of blood in the sputum.
  • In the lungs, the veterinarian can listen for wheezing.
  • Heat in the body, cramps.

Against the background of all these symptoms, the manifestation of other specific signs of the disease is possible:

  • a sharp loss of body weight;
  • poor appetite is present;
  • the pet often and strongly itches, hair falls out.

Symptoms and their intensity depend on how long the parasites have lived in the dog's body and how much the destruction of internal organs has occurred.

Laboratory confirmation of the diagnosis

If at least one warning symptom appears, the pet should be shown to the veterinarian. Timely diagnosis of the disease can save the dog from serious consequences associated with damage to the heart and lungs.

  • The most accurate method for diagnosing dirofilariasis in dogs is a rapid test for the presence of antigens in adult female dirofilariae. The result becomes known within 10 minutes. A blood test is also used to determine the effectiveness of treatment for a disease.
  • An immunological study of blood allows you to determine the amount of antibodies produced by the body in response to the ingress of parasites.
  • The ECG helps detect changes in the heart muscle and determine the rhythm.
  • The examination should include echocardiography. Results may show pulmonary hypertension, right ventricular changes.
  • A chest x-ray can show changes in the size of the pulmonary arteries, as well as enlargement of the right ventricle and atrium.

A false negative laboratory test result may be due to a small number of parasites, the predominance of males among parasites, or the rapid development of helminths, as a result of which they quickly penetrate the pulmonary arteries.

Diagnosis of cardionematodes

In the initial stages of infection with dirofilariasis, the diagnosis of the disease is very difficult. Clinical manifestations of pathology are similar in nature to diseases of the respiratory tract and cardiovascular system. When making a diagnosis for heartworms, it is necessary to carry out comprehensive examinations of the animal.

Making an accurate diagnosis for the presence of worms in the heart in dogs consists in collecting an anamnesis of the pet, as well as a thorough examination of the animal. It is advisable to use X-ray and ultrasound studies.

This type of diagnosis allows you to determine hypertension in the lungs of a chronic nature, with the development of which the resistance of the vessels increases (provoking right-sided myocardial insufficiency).

Accurate diagnosis of cardionematodosis includes a biochemical blood test. It also takes into account the results obtained after using special test systems that help determine the presence of microfilariae in the pet's bloodstream.

Treatment of the disease

In the event that dirofilariae were found in the dog's blood, the following drugs may be prescribed.

  • Arsenamide is an arsenic drug that is active against adults only. The solution is injected intravenously at 0.001 g per 1 kg of the dog's body weight. The course of treatment is two weeks.
  • Diethelcarbamazine (Carbilazine, Ditrazin, Dicacid). The drug is effective against larvae. To a lesser extent, it is active in relation to adults. The dosage is calculated as 0.025 g per 1 kg of body weight of the animal, which is administered three times a day for three weeks. As a preventive measure, in the summer, during the period of mosquito activity, the dosage is maintained, but the duration of treatment is reduced to 7 days. The course can be repeated every two months.
  • Levamisole. This drug is effective to treat dirofilariasis at the initial stage of development. Assign 0.01 g per 1 kg of dog weight. Kills larvae and adult female dirofilariae. The drug does not apply to their males.
  • Filarsen (Dichlorfenarsin, Halarsol). Only affects adults. Give the animal three times a day at a dosage of 0.01 g per 1 kg of body weight. The duration of treatment is 10 days.
  • In dogs, treatment is often done with Immiticide. It is injected intramuscularly (in the area of ​​the lumbar muscle). The dosage is 2.5 mg per 1 kg of body weight of the dog. Two injections are enough with an interval of 24 hours.

In addition to anthelmintic drugs, the treatment of dirofilariasis in dogs is accompanied by the intake of other drugs: drugs that restore the activity of the heart and circulatory system, immunomodulators, antihistamines, hepatoprotectors, enterosorbents.

If you have to be treated at home, then you need to follow some rules. During treatment, the dog should be protected from activity. Better to put her in a cage. Walking should be limited to 5-10 minutes and only on a leash. She can return to full physical activity 6 months after the start of the treatment course.

If the treatment does not respond to conservative treatment, surgical intervention is prescribed. During the operation, worms are removed from the atrium. Thus, the number of adults capable of breeding decreases.

In the future, treatment is continued with anthelmintic drugs. Symptoms gradually decrease in intensity and recovery occurs.


Before prescribing an antidirofilarial drug, it is necessary to find out if the pet has any diseases in which such treatment is contraindicated. If dirofilariae are detected by an X-ray or echocardiographic method, cardiac and pulmonary pathologies must be eliminated before taking adultery. Further treatment is the same as with a low degree of worming.

Adjunctive therapy

Mandatory for all treatments. Corticosteroids are used, which have an anti-inflammatory effect, as well as heparin, which prevents thrombus formation.

Operative treatment

The veterinarian has no more than 48 hours to save the pet in the event of a severe venous circulation disorder. Ancillary treatment is performed before and after the operation.

Helminths are removed from the atrium and vena cava. The alternative method for removing parasites from the pulmonary arteries is difficult and dangerous. After the operation, adultery is performed.


You can avoid infection with heartworms if you follow a number of rules. Particularly attentive to the prevention of dirofilariasis should be taken by the owners of dogs in regions that are unfavorable for helminthiasis.

It is important to carry out routine deworming of dogs in a timely manner, especially in the period before the onset of mosquito activity.

Before traveling out of town, it is important to treat your pet's hair with special repellents and means to prevent mosquito and mosquito bites. Routine diagnostics of the dog's health once a year will also help avoid possible infection with dirofilirosis.

At the first characteristic symptoms of a pet's ill health, you need to seek help from a veterinary clinic. Treatment of heartworms is most advisable in the early stages of the disease and the prognosis will be favorable.

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