Anaplasmosis is a tick-borne disease. Two types of infections can happen: granulocytic anaplasmosis and infectious cyclic thrombocytopenia. Granulocytic anaplasmosis is more common, but your canine companion can have both infections at the same time.

Ixodes tick which transits Lyme
through feeding
Ixodes tick which transits Lyme
through feeding

Transmission is via a tick. A tick needs to be attached for a minimum of 24 hours to transmit the organism. Incubation time is about 1 to 2 weeks. Reservoir hosts – a source of infection and possible reinfection that sustains a parasite – are usually other animals such as small rodents and deer.


Blood tests and a urinalysis are the main diagnostic tools for anaplasmosis. The blood tests usually include a complete blood count, blood smear evaluation, biochemistry panel, serology to look for antibodies, and polymerase chain reaction (PCR) assays. If the dog is lame from severe inflammation, which can accumulate in the joints, x-rays and analysis of joint fluid are often recommended.


Treatment includes antibiotics, and, if pain is present, anti-inflammatory drugs and other types of medication for pain.

Doxycycline is the most commonly used antibiotic. Most dogs respond within one to two days after they first take doxycycline. Other antibiotic options are tetracycline or minocycline. Your veterinarian will pick the medications best suited for your pet’s issue.

Disease Prevention

Appropriate tick control is critical to preventing this disease. Preventing ticks from attaching and removing any ticks from your pet within a few hours of attachment is vital.

Note: Dogs with anaplasmosis may also be infected with other tick-borne organisms such as Ehrlichia, Borrelia (the causative agent for Lyme disease) and more, so infected dogs should be screened for those diseases too.

Granulocytic Anaplasmosis

Granulocytic anaplasmosis is an infection of white blood cells. It is caused by Anaplasma phagocytophilum. Granulocytic anaplasmosis is seen most commonly in dogs in the Northeastern, upper Midwest, and coastal western United States.

Since granulocytic anaplasmosis requires the Ixodes tick as its vector, seasonal outbreak of the disease can occur from spring through summer. Symptomatic disease is most often seen in adult dogs, and golden retrievers and Labrador retrievers appear more sensitive to getting it than other breeds. 

Anaplasma phagocytophilum is transmitted via a bite from an Ixodes tick. Ixodes scapularis (often commonly called the deer tick, blacklegged tick, or bear tick) is the primary tick carrying the disease in the Midwest and Northeastern United States; Ixodes pacificus (commonly called the Western blacklegged tick) is the primary vector in the Western United States.

These ticks can infect a wide range of mammals. In addition to dogs, clinical disease has been documented in cats, cattle, sheep, goats, llamas and even people.

Because of common vectors and rodent reservoirs, an animal can also be co-infected with Borrelia burgdorferi can be seen and can lead to more severe illness.

Many dogs exposed to granulocytic anaplasmosis do not get obvious signs of the condition. If signs are seen, they most often occur during the early phase of infection, which is 1 to 2 weeks after transmission.

The signs may be vague and include lethargy, lack of appetite, and fever. Some dogs may become lame because their joints are painful. Less common signs include vomiting, diarrhea, coughing, and difficulty breathing. The prognosis for granulocytic anaplasmosis with treatment is quite good.

Infectious Cyclic Thrombocytopenia

Infectious cyclic thrombocytopenia is an infection of blood platelets. It is caused by Anaplasma platys.Anaplasma platys transmission has not been fully determined, although tick vectors are probable. The organism has been found in Rhipicephalus and Dermacentor ticks.

Rhipicephalus tick
Rhipicephalus tick

Signs include lack of appetite, lethargy, fever, bruising on the gums and stomach, nosebleeds from the lack of platelets, which are a part of forming clots, and weight loss.

Many dogs with infectious cyclic thrombocytopenia have only mild clinical disease, so prognosis is generally good. These cases can become critical, however, if the platelets get low enough to cause bleeding disorders. 

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