Die wichtigsten Parasitosen beim Hund: Welche Arten gibt es und wie kannst Du sie erkennen

The most important parasitoses in dogs: What types are there and how can you recognize them?

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Dr. Karin Schlotterbeck

Parasitosis is widespread and can be a serious disease for our dogs. In this article we will look at the differences between endoparasites and ectoparasites and explain the different types. It's also about the effects on the dogs and prophylactic options.  

How do parasitoses spread?

In dog parks, animal shelters and dog boarding kennels where there is a high density of dogs, parasites can quickly spread from one dog to another.  

Due to the increasing number of dogs being taken to Mediterranean countries, for example, and the increased import of dogs through animal protection projects from southern and eastern Europe, more and more “exotic parasitoses” are being diagnosed by veterinarians, such as leishmaniasis, babesiosis or dirofilariasis .

Some parasites can be transmitted from animals to humans and can also cause diseases (so-called zoonoses) in humans. Since healthy dogs can be infected with parasites even without noticeable symptoms, a regular external inspection of the dog and also a regular stool examination should be carried out and appropriate antiparasitic drugs should be used regularly in order to keep the risk of infection low. Parasitosis can be particularly dangerous for young, old and immunocompromised animals and people.  

People and animals infected by the parasite are called hosts . A distinction is made between the final host on which the parasite reproduces and the intermediate host that it requires for its further development (e.g. from egg to larva) and spread. If the host has become infected with a parasite, it takes a specific period of time for the parasite until, for example, eggs are excreted.

Due to climate change, intermediate hosts such as certain ticks and sand flies are increasingly feeling at home here, so these diseases will also manifest themselves here.  


Endoparasites are worms and protozoa that live in internal organs such as the intestines, lungs or heart.  

Protozoa (single-celled organisms)  

Giardia : These protozoa are increasingly found in dog feces and cause varying degrees of diarrhea, especially in puppies. The excreted oocysts (comparable to worm eggs) are ingested orally. Giardia treatment is often very difficult because reinfection occurs quickly. Extensive hygiene measures must be taken with special disinfectants in order to also treat the environment contaminated with Giardia.  

Leishmania : These protozoa are transmitted by certain mosquitoes and have so far mainly occurred in central and southern Europe . Symptoms include skin changes, lethargy, weight loss, anemia and kidney damage. The therapy and check-ups are quite complex and should last a lifetime.  

Babesiosis : Babesia is transmitted by certain ticks (Dermacentor and Rhipicephalus) and is now spreading more and more in Central Europe. They attack the red blood cells (erythrocytes) and lead to corresponding symptoms such as anemia, jaundice (jaundice), fever and an enlarged spleen. It is a life-threatening illness (see article travel illnesses). Other protozoa include Anaplasma, Neospora and Toxoplasma.  

Worms (helminths)  

A distinction is made between roundworms, hookworms, tapeworms and whipworms, which parasitize in the small and large intestines of dogs. A massive infestation can lead to diarrhea and weight loss, especially in puppies. In addition to oral ingestion, some worms can also be transmitted from mother to puppies via the uterus or milk. Transmission via the skin is also possible. The small fox tapeworm, which can also infect our dogs, can be life-threatening for humans. Some worms don't just live in the intestines, such as the lungworm. It lives and reproduces in the lungs. The larvae are coughed up, swallowed and then excreted in the feces. A special feature is the imported heartworm, which resides in the heart and pulmonary arteries and leads to reduced resilience and breathing problems. It is transmitted by certain mosquitoes as intermediate hosts.  


Ectoparasites are mites, hair lice, lice, fleas and ticks, for example, that reside permanently or temporarily on the surface of the body.  


They are widespread and not host specific. For example, if there is not a dog as a host, the flea also likes to attack humans as a substitute host. It transmits tapeworms, sucks blood and causes itching, skin irritation and allergies. If the infestation is very severe, anemia can occur .  


They are transmitted through direct contact with grasses and bushes. They suck blood and can transmit dangerous diseases such as babesiosis, anaplasmosis and Lyme disease.  


These include Sarcoptes and Demodex mites. They cause severe itching, dull fur and occasional hairless scaly patches on the skin. Some are very contagious and are spread from dog to dog and through blankets or brushes. The ear mites colonize the ears and cause severe itching and ear infections. Autumn grass mites usually attack dogs in August to October and are visible as small red dots. They temporarily cause severe itching and are easy to treat.  


The diagnosis can usually be made through fecal, skin and various blood tests as well as possibly further biopsies or smears.  


There are a variety of effective remedies against ecto- and endoparasites. In some diseases such as For example, leishmaniasis or heartworm infestation, therapy can be very complex and expensive.  


Regular preventative treatment must be coordinated individually with the veterinarian and can be significantly less time-consuming and stressful than treating infections. A distinction is made between tablets, spot-on preparations, pastes and collars. There are vaccinations against Borrelia and Leishmania, but they do not replace basic prophylaxis.  


Untreated parasitoses can lead to chronic health problems, irreversible damage and even death. The course depends on the type of parasite, the dog's health and the effectiveness of the therapy. These are serious health problems that can be caused by various parasites. Preventative care and regular veterinary checks are crucial to preventing or early detection of infections. Proper therapy, based on an accurate diagnosis, can often restore the dog's health and prevent long-term complications.