What Is Anaplasmosis in Dogs?

Anaplasmosis is caused by ticks and usually only causes mild disease in dogs.


Anaplasmosis is a tick-borne bacterial disease in dogs caused by the anaplasma genus of bacteria. If an infected tick is on your dog for 24 hours or more, your dog may become infected. Fortunately, Anaplasmosis infection typically only causes mild disease if your dog gets sick at all.

How serious is anaplasmosis? It normally is not serious. The dog’s immune system usually clears this infection quickly without treatment.

Anaplasmosis Symptoms in Dogs

Signs of an anaplasmosis infection usually occur during the first couple of weeks after infection. They’re often vague and easy to miss, but typically include:

  • Lethargy
  • Decreased appetite
  • Fever

Occasionally, the dog appears stiff with painful joints. You also may see:

  • Vomiting
  • Diarrhea
  • Cough

There are two forms of anaplasmosis, which are spread by a few different ticks but most commonly the deer tick. The bacteria transmitted by the tick bite gets into either the dog’s white blood cells or platelets, depending on which form is involved. The most common form of anaplasmosis affects the white blood cells. Bruising and nose bleeds may be observed if platelets are affected.

Screening for Anaplasmosis

Most annual screening heartworm/tick tests include Anaplasma, so the diagnosis is simple. If your dog shows any symptoms of anaplasmosis and tests positive for anaplasmosis, your veterinarian will likely recommend further testing including a complete blood count (CBC), chemistry screen, and urinalysis. Treatment is typically doxycycline, an oral antibiotic. If your dog is in pain, a non-steroidal anti-inflammatory drug (NSAID) or other pain management may be prescribed.

If your dog tests positive for anaplasmosis on a routine screening test but has no symptoms, your doctor may recommend a CBC and urinalysis just to be sure all is well. If everything looks good, treatment is not necessary.

Dogs who test positive for both anaplasmosis and Lyme disease, another tick-borne bacterial disease, tend to show signs of illness more frequently. If this happens to your dog, follow your veterinarian’s advice regarding further testing and treatment.