Bartonella species are harmful bacteria that cause infections in humans and animals. It was initially thought that these bacteria only caused a “mild, acute, and self-limiting illness,” according to LymeDisease.org. However, emerging research suggests that this is not always the case.
Research over the last decade has begun to recognize that Bartonella species, like B. henselae (cat scratch disease) or B. quintana, can can cause difficult to diagnose disease that affects multiple body systems including the eyes, heart, and brain. Bartonella species primarily live in cells lining the blood vessels (endothelial cells) and red blood cells allowing them to easily cycle in and out of the bloodstream. This often results in a recurring infection that is difficult to detect on standard testing and may cause non-specific symptoms that mimic many other health conditions, like autoimmune disorders.