Heartworm disease

Keeping dog

In recent years, due to climate change, mosquito species that spread heartworm have also appeared in the Carpathian Basin.

Heartworm disease is a serious problem that can even lead to the loss of the animal – we have to take it seriously!

How does heartworm get into a dog?

The causative agent of heartworm (Dirofilaria immitis) enters the animal’s body through the bite of infected mosquitoes. (Very rarely, the disease can also develop in cats and ferrets).

The microscopic larvae reach the heart and the large vessels of the lungs after 6-9 months of migration.

How can heartworm be detected?

Adult heartworms (provided that both sexes are present in the body) reproduce. In the blood circulation, the so-called Stage 1 larvae (offspring of adult worms) can be detected in the blood smear by microscopic examination.

Dirofilaria larva

Dirofilaria larva

Another option is a serological test to detect the body material of female worms. These testing methods are fast and provide results in minutes.

What to do if the tests are positive?

In such cases, additional laboratory tests are needed to confirm the diagnosis of the disease.

If our pet shows symptoms of heartworm (cough, shortness of breath, tiredness, sometimes fainting) a chest X-ray and an ultrasound examination of the heart will also be necessary.

What symptoms does the disease cause, when can we suspect heartworm disease?

Adult heartworms are found in the great vessels of the lungs and in the cavities of the heart.



At the beginning of the disease and when a small number of worms are present, there are no symptoms, or mild symptoms may develop.

In more advanced cases, we see symptoms of heart failure. Shortness of breath, suffocation, fatigue, and frequent coughing appear.

Caution! These symptoms are inherent in other heart diseases, a thorough examination and accurate diagnosis are important!

Can heartworm be treated?

Several methods and protocols are known for the treatment of the disease.

The chosen treatment method depends on the stage of the disease, the severity of the symptoms and the financial possibilities of the host. It is a basic fact that asymptomatic or minimally symptomatic dogs can be treated more successfully and at a lower cost. Therapy for dogs showing symptoms of heart failure (difficulty breathing, coughing, fatigue) is more risky.

The best method is prevention!

Annual screening test and use of preventive preparations throughout the year!

It is recommended to carry out the test annually to check the effectiveness of the treatment, even if preventive preparations are used continuously.

What should be done if we want to avoid heartworms?

Regular screening is most important!

Screening examinations are recommended annually for dogs older than 6 months (screening dogs younger than this does not make sense, as the worm develops in the animal’s body during this time).

Heartworm Resistance in Dogs | Oakland Veterinary Referral Services

In the case of cats and ferrets, the occurrence of the disease is much rarer, but screening may be justified in their case as well. If the tests do not reveal the infection, the emphasis should be placed on prevention.

Fortunately lthere are tablets and sprayable products that can be used regularly to prevent the disease !

Caution! These preparations should only be used in worm-free dogs!

When used in dogs infected with heartworms, they can cause serious symptoms, even death! Therefore, the screening must be carried out first and then the preventive treatment can follow.

The disease is spread by mosquitoes, so it is advisable to use external antiparasitic preparations that (also) affect mosquitoes. Dogs living in areas heavily infested with mosquitoes near waterfronts are more likely to become infected.

If you want to be safe, please

protect yourself from the threat of heartworms, have an annual screening test and use a preventive product all year round!

We are waiting for you with your pet at our screening test!


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