Diseases and Medical Information

Anaplasma Positive: What does this mean for your dog?

Your pet has tested positive for exposure to Anaplasma on a tick screen test. Anaplasma (formerly called Ehrlichia equi) is a bacteria carried by deer ticks. These bacteria can cause severe health problems such as high fevers, swollen painful joints, vomiting, brain disease and disorders of the immune system. Not every dog infected with these bacteria will become sick,  however. Dogs can get Lyme and Anaplasma infections at the same time. Dogs with multiple infections are more likely to get sick and the sickness can be worse.

The tick screen test that was performed on your dog detects antibodies, which are proteins produced by white blood cells in order to fight infection. A positive test means that at some point in time your dog was bitten by a tick and infected with Anaplasma. This test will turn positive about 10-14 days after infection. Many dogs will fight off and clear the infection on their own. Some dogs will not and these are the dogs that can become sick.

Unfortunately, we cannot tell if your dog has an active infection based on this test alone. We know that your dog was infected at least two weeks ago, possibly many years ago. We need to determine if the infection is active. Dogs with active infection should be treated with antibiotics. Dogs that do not have active infections do not need treatment. Unnecessary treatment has the potential to cause antibiotic resistance in some bacteria and produce side effects in your dog. We only treat active infection.

  1. If your dog has a fever, fluid inside the joints, or any other sign or tests that fit with an active infection, we will treat your dog with antibiotics. If your dog also tested positive for Lyme (and has never had treatment), we will recommend antibiotics.
  2. If your dog is not showing clinical signs, we need to run tests to see if there are active bacteria in the system. The first test we recommend is a complete blood count. Most dogs with active infections will have changes on this test, so if we see changes, we treat. If the test is normal, we most likely won't need to treat.
  3. We can collect a blood sample for a PCR test. This test looks for Anaplasma DNA in the blood and if it is positive it means there is an active infection. We have to send this test out to an outside laboratory. The downside is that it may take weeks to get results and it is fairly expensive.

In order to prevent problems in the future, there are a few steps we need to take.  Your dog needs to be on good tick control from April to November. We recommend Nexgard or Frontline monthly. In heavy tick areas, we combine Nexgard or Frontline with a Preventic collar to get maximum protection. There is no vaccine available for this disease. Dogs may test positive for many years after an infection, even if the infection is not active. Dogs that test positive need to have their cell counts checked every 6-12 months to make sure there are no problems. Discuss this with your veterinarian if you have any questions.

AHS Protocol vs. "Slow Kill"


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