CONDITION
Anaplasmosis
Anaplasmosis is an infection caused by bacteria transmitted through tick bites. The bacteria—most commonly Anaplasma phagocytophilum—invade a type of white blood cell called neutrophils, which can trigger signs of illness in some dogs, while others remain symptom-free despite testing positive. Owners may notice a period of lethargy, reduced appetite, or fever days to weeks after a tick has been found or suspected. In other cases, the infection is discovered incidentally during routine blood work in a dog who appears entirely well. Dogs with clinical signs typically respond within a day or two once antibiotic treatment begins, while those without symptoms may simply be monitored. This page explores what anaplasmosis can look like, how the infection develops, the ways it is identified through testing, and the approaches used when treatment is warranted.
Why this matters now
Signals & patterns
Early signals
Later signals
Click to read about the biological mechanisms
How this is usually investigated
Options & trade-offs
Related conditions
Ehrlichiosis
Ehrlichiosis is also transmitted by ticks and causes bacteria to live inside white blood cells, producing clinical signs that can overlap with anaplasmosis—including fever, lethargy, joint pain, and low platelet counts. Dogs in tick-endemic areas may carry both infections simultaneously, and distinguishing between them often requires specific blood tests.
Babesiosis
Babesiosis is another tick-borne infection that can occur alongside anaplasmosis in dogs exposed to ticks. While babesiosis destroys red blood cells and anaplasmosis affects neutrophils, both may cause fever, lethargy, and pale gums, and co-infection can complicate the clinical picture.
Immune-Mediated Polyarthritis
Immune-mediated polyarthritis can present with joint pain, stiffness, and fever similar to what may be seen in dogs with symptomatic anaplasmosis. In some cases, tick-borne infections including anaplasmosis are investigated as potential triggers or concurrent conditions when a dog develops signs of inflammatory joint disease.
Lyme Nephritis
Lyme nephritis is a severe kidney complication that can develop in dogs infected with Borrelia burgdorferi, another tick-borne bacterium. Dogs with tick exposure may test positive for multiple tick-borne organisms, and distinguishing immune-mediated kidney inflammation from direct infection effects can be part of the diagnostic process.
Portosystemic Shunt
Portosystemic shunt can cause episodes of lethargy, poor appetite, and vague signs of illness that may prompt tick-borne disease screening in young dogs. While the underlying mechanisms differ entirely, both conditions can appear on a differential list when a dog presents with non-specific signs and abnormal blood test results.
Last reviewed: Invalid Date ·