Hepatozoonosis in Dogs

Hepatozoonosis is a dangerous infectious disease in dogs. This advisory article explains symptoms, occurrence, and treatment.

What is Hepatozoonosis?

Hepatozoonosis is an infectious disease that occurs in dogs, cats, and foxes. The disease is caused by parasitic unicellular cells of the genus “Hepatozoonon”. In the first step, these attack the monocytes and lymphocytes, which belong to the white blood cells. In the further course of the disease, the pathogens attack the cells of the spleen, liver, lungs, muscles, and bone marrow.

Transmission of Hepatozoonosis to the Dog

The disease is mainly transmitted orally. If a dog swallows or chews an infected tick, the pathogens enter the gastrointestinal tract. As a next step, the protozoa penetrate the dog’s intestinal wall. In addition, hepatozoonosis is spread through close contact with infected foxes (e.g. when fox hunting) or from a pregnant female to her pups.

Humans cannot get infected by their infected dogs. Consequently – despite the misleading name – it is not a zoonosis.

Hepatozoon Canis: Occurrence

Like Ehrlichiosis, hepatozoonosis is one of the so-called Mediterranean and travel diseases. The brown dog tick is the host of the parasitic unicellular organisms (Hepatozoonon canis) and is, therefore, a vector. This type of tick occurs mainly in warmer countries in southern Europe. The arachnid is also native to parts of Africa and Asia. Even in America, dogs are not immune from infectious diseases. There, the Gulf Coast tick transmits the disease through another genus of a pathogen called “Hepatozoonon americanum”.

Hepatozoon Canis: Symptoms in the Dog

The symptoms of hepatozoonosis are non-specific and can easily be linked to other diseases.


  • fever;
  • loss of appetite;
  • fatigue and exhaustion;
  • swelling of the lymph nodes;
  • pale mucous membranes;
  • diarrhea;
  • apathy;
  • weight loss.


  • stiff gait;
  • lameness;
  • Impairment of the central nervous system;
  • tenderness in the lumbar region;
  • muscle pain;
  • seizures that resemble epilepsy.

Hepatozoonosis: incubation period

The period of time between infection and the appearance of symptoms (incubation period) is around two to four weeks. However, quite a few affected dogs show no symptoms. The infectious disease often only becomes noticeable in combination with another parasitic infestation – for example in babesiosis or leishmaniasis – or in the case of an immune deficiency.

Hepatozoonosis: Diagnosis

The veterinarian uses a microscope and a blood or tissue sample to determine whether the dog carries pathogens. Further targeted examinations for a diagnosis are a PCR test or an antibody test. Giemsa staining is used in acute hepatozoonosis.

In advance, the veterinarian asks about previous trips to risk areas or, in the case of an adoption, about the dog’s country of origin.

Hepatozoonosis: Treatment and Therapy

Hepatozoonosis can be fatal without treatment. As with many diseases, the principle: “The earlier it is detected, the better!” Unfortunately, even with a timely diagnosis, the unicellular organisms of the hepatozoonosis genus cannot be completely eliminated. However, the course of the disease can be brought under control with early treatment and thus be milder.

Various antibiotics and anti-protozoal drugs are used in therapy. The latter are drugs that belong to the antiparasitic class and are used for infections caused by single-cell pathogens.

Protect Dog From Hepatozoonosis

A vaccine against hepatozoonosis is not available. But there are other measures that significantly reduce the risk for the dog to get sick.

  • Use a reliable anti-tick repellent to keep the bloodsuckers away from the dog. Pay attention not only to effective protection but also to good tolerance.
  • After walks, it is advisable to always carefully check the dog for ticks. Particularly popular parts of the body are the neck, head, shoulders, and chest.
  • Consider traveling to high-risk areas with your four-legged friend. This is especially true of immunocompromised four-legged friends.
Alice White

Written by Alice White

Alice White, a devoted pet lover and writer, has turned her boundless affection for animals into a fulfilling career. Originally dreaming of wildlife, her limited scientific background led her to specialize in animal literature. Now she happily spends her days researching and writing about various creatures, living her dream.

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