Bartonellosis

Bartonellosis is an infection caused by bacteria of the Bartonella genus, which can affect dogs and cats in different ways. These bacteria are typically transmitted through bites, scratches, or contact with fleas, and they can establish persistent infections that may affect the blood, immune system, heart valves, or other organs. In many cases, infected animals show no signs at all, though some develop fever, lethargy, inflammation in various parts of the body, or less common patterns involving the heart, eyes, or nervous system. Owners often arrive at this page after a positive test result in an animal that appears well, or after episodes of unexplained fever, lameness, or swelling that have been difficult to link to a clear cause. Because the signs can be subtle, intermittent, or absent, and because these bacteria are found in healthy animals as well as unwell ones, the question of what the test means for a particular pet is often central. This page explores what patterns of illness can be associated with Bartonella infection, how the bacteria interact with the body, how infection is detected and interpreted, and what approaches exist when treatment is considered. The aim is to help you understand what may be happening and what conversations may follow.