Anaplasmosis in dogs

Anaplasma (A.) phagocytophilum is the causative agent of anaplasmosis, a bacterial disease
which is transmitted through bites from ticks of the genus Ixodes. A. phagocytophilum is a gram‑negative,
obligate intra‑cellular bacterium which attacks mostly neutrophilic granulocytes, but also, in rare cases, eosinophilic granulocytes. Anaplasmosis occurs worldwide, its prevalence depending on the distribution area of the transmitting vectors.

There are different names for the clinical picture of an infection with A. phagocytophilum in dogs: granulocytic
ehrlichiosis (obsolete), canine granulocytic anaplasmosis, and, simply, and most frequently used: anaplasmosis.
Clinical symptoms of canine anaplasmosis include a reduced general condition with fever, weight loss, vomiting,
dyspnoe, spleno‑ and hepatomegaly, lymphadenopathy, oedema of the joints, leukopenia, anaemia, haemorrhagia, polyarthritis and CNS symptoms as a result of inflammation and bleeding in the meninges. In some dogs the immune system is able to eliminate the pathogen, others show an asymptomatic or chronic course. In the chronic form, alternating lamenesses may occur due to polyarthritis.

Antibodies against A. phagocytophilum occur in the serum of infected animals after seven to fourteen days. Different techniques are used for the serological detection of antibodies, such as ELISA or indirect
immunofluorescence test (IIFT). It needs to be taken into consideration that many dogs show specific
antibodies against A. phagocytophilum but are not clinically conspicuous. For diagnosis, it is hence necessary to investigate two blood samples at a time interval. A twofold titer increase or a seroconversion are here diagnostically relevant. If the first blood sample tests negative, a second sample should be examined after two weeks in cases of suspected anaplasmosis since dogs and horses do not produce antibodies in the early phase of infection. Borreliosis should be excluded by differential diagnosis. As of yet, no vaccines are available for dogs.

• Anti-Anaplasma phagocytophilum ELISA Dog (IgG)