Borrelia is a pathogen known to cause Relapsing fever and Lyme Disease.

Depending on the strain of Borrelia, the bacteria will be more or less likely to spread through the bloodstream to distant sites in the body. When it does spread, it can cause arthritic, neurological, cardiovascular and other symptoms.

Animal studies have shown that Borrelia burgdorferi can be found in many tissues and organs including the skin, joints, heart, brain, bladder and other sites of untreated animals as well as in animals who receive antibiotic treatment .

The bacteria tends to be found in low numbers in tissues. Aside from the initial infection, Borrelia does not appear to circulate in the blood which is why it is so difficult to detect