Personal Health

Heart worms: risk for dog and human?

The heartworm Dirofilaria immitis infests as a parasite to many different Säugtiere. Its main natural hosts are dogs and other dog-like (such as foxes and wolves). Mosquitoes transmit heartworms from one animal to another – or to the people.

Thus, the development and Transmission of heart worms in Each of the runs:

  • The adult heart worms, also macro filaria called, colonize internal organs of their host. The female specimens can be up to 30 inches long, male 18 inch.
  • Female sex Mature heart worms don’t lay eggs, but produce small, only about 220 to 340 microns long worms the Microfilariae. These enter the blood of the host.
  • Now, if a mosquito bites the host, takes up the microfilariae when blood eyes. In the mosquito to develop the Microfilariae to be capable of infection larvae more, the proboscis of the mosquito Hiking.
  • Stings, the mosquito is now a different animal or a human, the heart worm larvae through the resulting puncture channel is active in the new host penetration.
  • In the newly infected host, the larvae develop within months or years (no earlier than 180 days after the infection) to full-blown heart worms.
  • As soon as you Mature are, multiply the heart worms in the affected organs, and can so continue to spread.

However, the man for heart worms a wrong host. This means that If a mosquito heartworm larvae transfers to a human, can develop the larvae in its body to adult worms, but do not become sexually Mature and is therefore not a communicable Microfilariae produce.

The most important facts about the infection:

  • Heartworms infected animals can infect other animals or humans directly.
  • Infected people play in the Transmission of heart worms, not a role.

What happens after infection?

In the dog, caused by an infestation of heartworms, a severe to fatal disease: heartworm disease (or cardiovascular Dirofilariosis).

Because the Mature heart worms in dogs mainly from the heart to the lungs leading pulmonary artery (pulmonary artery) and the right heart. The worms can block the artery and lead to severe Cardiac dysfunction.

Adult heart worms in a dog with a lifespan of up to seven years. Without treatment, the infected dogs usually die.

When people settle the heart worm larvae, especially in the lungs and in the lower layer of the skin (subcutis), and rarely in other organs such as the liver and the eye. Since man is not an optimal host for heart-worms, to die, however many larvae already on their way through the tissue under the skin.

If adult heart dying worms, which leads to inflammation at the respective place. As a response, can small nodules (or granulomas) to form.

In the lung, the heart worms as a pulmonary Dirofilariosis described the disease trigger. In addition to the nodule formation can to a pulmonary infarction when the heart worms, lung vessels clog. The nodules are seen on x-rays of the chest area as a small round of changes. Doctors refer to these as the lung, around the herd.

Most of the lung infection caused by heart worms, no complaints. If the pulmonary Dirofilariosis power I felt, then, for example, by

  • Fever,
  • Coughing (including coughing up blood),
  • Chest pain and/or
  • Shortness of breath.

By the way: pulmonary round lesions are not specific for heart worms, but can also be other causes – such as cancer. A randomly discovered lung around the stove leads to the removal is typically further examinations, including tissue, the diagnosis to be clarified. Most often, the pulmonary Dirofilariosis is discovered in humans on the basis of such tissue samples.

Where there is a risk of infection?

Heart worms are in large Parts of America, Africa, South Asia, Japan and Australia is widespread. Moreover, they come in numerous regions in southern and South-Eastern Europe before – including the Islands of the Mediterranean. So there where a lot of people from Germany take a vacation.

Many of the mosquito species from the three genera Culex, Aedes and Anopheles are considered as Vectors of the parasites. Their season lasts at least from April to October.

Some of these mosquitoes are also in Central Europe, widely used. However, in General, are the local temperatures for heart worms too low, the mosquitoes develop: below 14 degree Celsius is not development in the mosquito instead.

However, there is always the possibility that heartworms infected mosquitoes North of the Alps spread and heart worms in this country permanently at home are. The most important prerequisites for this would be that

  • the average temperatures in the context of climate change increase and
  • in this country there is a sufficient number of infected dogs.

Also dogs that are brought about due to animal welfare reasons, Germany can contribute to the spread of heart worms: of More than five percent of the so-called import dogs have a heartworm infection.

How quickly the heart worms can spread without adequate counter-measures, for example, in the USA, Where the parasites, which were initially only a few in Florida have spread, within 50 years all over North America.

Meanwhile, several Hundred cases are known in which people with heart worms have infected the majority occurred in the United States.

What protects against infestation by Heartworms?

The best protection is to avoid the distribution areas of heartworms and their vector mosquitoes, or at least dogs don’t have to travel there to take.

Who is still in a risk area goes, should be sufficient mosquito protection concerns:

  • You leave as little skin as possible uncovered.
  • You use (and your dog) insect repellent if they are exposed to mosquitoes.
  • You sleep under a (with insecticide-treated) mosquito net if mosquitoes are able to find their sleeping place home.

If you come during the mosquito season with your dog in a high-risk region want to travel, you should to him, in addition to a medium that transmitted heartworm larvae kills before this is the heart of the dog’s reach. Let the best of a veterinarian explain how this preventative treatment with a parasiticide should be applied.

By the way: in Switzerland, The usual vermifuge for dogs and cats, protects against heart worms. Nonetheless, the regular de-worming is important because of the infestation with native worms for the dog and cat can have serious health consequences and can be transmitted to humans is.

What to do against an infestation of heart worms?

The dog is an existing heartworm infection is difficult to treat. Only in the first four weeks after infection, a low dose of anthelmintic may prevent the larvae develop to adult worms.

Against later development stages of the parasite, such an agent can’t do anything more. Then chemotherapy and/or surgical removal of the adult heartworms are eligible.

When people with a heartworm infection, the optimal treatment in nodules in the lungs and under the skin surgically to remove: for example, a complete cure can be achieved. On medicines you can do without in many cases.


Online information of the Pschyrembel: (retrieval date: 14.1.2020)

Dirofilariasis. Online information from the Centers for Disease Control and Prevention (CDC): (retrieval date: 14.1.2020)

Online information of ESCCAP (European Scientific Counsel Companion Animal Parasites) Germany e. V.: (retrieval date: 14.1.2020)

Guideline for prevention of pathogen transmission by blood-sucking vectors of the dog. Online information of the German Federal Environmental Agency: (status: 1.3.2019)

Parasites in the approach. Online information the Free University of Berlin: (status: 13.4.2018)

Heartworm disease (Dirofilariosis) in the case of an imported dog. Online information of the Chemical and veterinary untersuchungsamts (CVUA) Stuttgart: (date: 21.3.2013)

Scheid, P. L.: parasites: a danger for humans and animals. Pharmaceutical Newspaper, Edition 46/2012 (12.11.2012)

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*The contribution of “heart worms: risk for dog and human?” is published by Onmeda. Contact with the executives here.