If you found a tick on your dog, there are a few steps you should take to see if it was carrying this disease to protect your pup from long-term damage.

Anaplasmosis [pronounced an-uh-plaz-moh-sis] can be caused when a dog is bitten by a tick carrying the Anaplasma phagocytophilum bacterium. This bacterium is carried by the deer tick or the western blacklegged tick, the same variety of ticks that carry Lyme disease. A less common form of anaplasmosis comes from the bite of a brown-dog tick carrying the bacterium Anaplasma platys.

Anaplasmosis has been reported in dogs in all 50 states, but most infections come from the Northeast, Upper Midwest, Southwest, and the West Coast. The Companion Animal Parasite Council's interactive maps show how anaplasmosis is distributed across the U.S. and Canada.

Symptoms of Anaplasmosis in Dogs

A dog infected with anaplasmosis may not have symptoms, but if he does have symptoms, they generally appear a week or two after being bitten by an infected tick.

Common symptoms of anaplasmosis include:

  • Lameness
  • Joint pain
  • Lethargy
  • Fever
  • Poor appetite
  • Vomiting
  • Diarrhea
  • Coughing
  • Labored breathing
  • Seizures
  • Bruising on the gums and belly
  • Bleeding (including nosebleeds)
Woman hiking with her black lab on a mountain forest path
Credit: Petes Photography / Getty

Testing and Diagnosing Anaplasmosis in Dogs

You should ask your veterinarian to test your dog for anaplasmosis if he displays any of the above symptoms or you know he has been bitten by a tick. Since it can take over a month for anaplasmosis to register on a blood test, check with your veterinarian to see how soon to come in for a test.

Even if your dog has not been bitten by a tick lately or does not show symptoms of illness, your veterinarian may also advise you to get your pup tested for anaplasmosis and other tick-borne diseases on an annual basis, especially in areas where ticks are common.

If your dog is being tested, your vet clinic will likely use an in-house blood test to quickly screen for anaplasmosis. The blood test generally also screens for heartworm, Lyme disease, and ehrlichiosis, so your vet may refer to it as a "four-way test." Since anaplasmosis and Lyme disease are carried by the same variety of tick, dogs can sometimes be infected with both conditions at once.

Because it tests for antibodies, a positive result means that your dog has been exposed to the bacteria, not necessarily that he has symptoms or will ever show symptoms. Dogs that have been treated for anaplasmosis may continue to test positive for several years due to antibodies staying in the bloodstream.

If your dog tests positive for anaplasmosis, your vet will likely do more thorough testing including a PCR (Polymerase Chain Reaction) test, a blood test, and urinalysis, says Anya T., LVT and claims adjuster at Embrace Pet Insurance.

Anaplasmosis Treatment for Dogs

As with other bacterial infections, anaplasmosis is treated with antibiotics. The Journal of Veterinary Internal Medicine recommends treatment with the antibiotic doxycycline for at least two weeks. Your dog's symptoms will likely start to improve within 24-48 hours, but you should continue giving him the full course of doxycycline.

Is Anaplasmosis in Dogs Contagious?

Anaplasmosis isn't contagious, Anya says. Your dog can't get anaplasmosis from another animal and he can't give it directly to you. The only way to get anaplasmosis is through a tick bite.

Preventing Anaplasmosis in Dogs

To protect your dog from anaplasmosis and prevent other tick-borne diseases, treat your dog year-round with flea- and tick-prevention medication as recommended by the American Veterinary Medicine Association and your own veterinarian.

You can find flea- and tick-prevention medications in topical, oral, and collar varieties. Not all preventive measures protect against all tick species, so ask your veterinarian which option is best for the types of ticks in your region.

Keep your lawn mowed short so it won't appeal to ticks and check your dog for ticks as soon as he gets home from spending time in a wooded or tall-grass area. If you live in an area with a high tick population, you may want to check your dog for ticks daily, Anya says.