Anaplasmosis in Dogs

What is anaplasmosis?

The causative agent of canine granulocytic anaplasmosis is Anaplasma phagocytophilum, a Gram-negative, obligately intracellular bacterium of the family Anaplasmataceae. Unlike Ehrlichia canis, it infects neutrophils, where it multiplies in morula-like inclusions. A related species, Anaplasma platys, infects platelets and causes infectious cyclic thrombocytopenia in dogs.

Transmission by Ticks

Anaplasma phagocytophilum is transmitted by hard ticks of the genus Ixodes; in Europe, this is primarily the common wood tick (Ixodes ricinus). Since the same vector also transmits Borrelia burgdorferi, co-infections occur. The pathogen has a broad host range and is of zoonotic significance as the causative agent of human granulocytic anaplasmosis; its distribution follows that of Ixodes ticks and is increasing as tick seasons lengthen.

Symptoms of Anaplasmosis in Dogs

Many infected dogs show no obvious symptoms. If clinical signs do appear, they usually occur during the acute phase one to two weeks after transmission: fever, lethargy, loss of appetite, and often lameness due to painful joints. Less commonly, vomiting, diarrhea, coughing, or respiratory distress may also occur. A decrease in blood platelets (thrombocytopenia) is a common laboratory finding. The prognosis is generally favorable.

Anaplasmosis Testing in Dogs

The clinical picture resembles that of other tick-borne diseases, particularly Lyme disease and granulocytic ehrlichiosis, and cannot be definitively diagnosed based on clinical signs alone. The detection of antibodies indicates an immune response to the pathogen; however, antibodies may not yet be present in the very early phase of infection. Due to the shared Ixodes vectors and the possibility of co-infections, it is advisable to test for Borrelia and Ehrlichia simultaneously.

Rapid Test Component

The Fassisi® combination tests CanVecto 3 and CanVecto 4 detect antibodies against Anaplasma phagocytophilum in serum, plasma, or whole blood, in each case together with other vector-borne pathogens. CanVecto 3 additionally detects antibodies against Borrelia and Ehrlichia canis, while CanVecto 4 additionally detects Dirofilaria immitis antigen as well as antibodies against Leishmania and Ehrlichia canis. This facilitates the identification of multiple pathogens from a single sample in cases of tick-borne diseases.

The technical details are documented on the Sources page.