Pathogenesis+- Lyme+Disease

When //B burgdorferi// enters the body it has a tropism to the skin, heart and central nervous system. A tropism means that the bacteria is attracted to those areas, so that is where it normally establishes infection. //B burgdorferi// evades the body's immune responses by staying localized until it is strong enough to infect other parts of the body. Staying localized results in a physical symptom of a rash that looks like a bulls eye, called an **EM rash**. These rashes prohibit neutrophils from attacking and destroying the bacteria.

//B burgdorferi// has a number of other ways it can evade the bodies immune system.

 * It can shed and change the antigens on its outer layer
 * It can hide in the extracellular matrix, essentially a space in-between tissue
 * It is also able to disable some functions of the compliment system

Once Lyme disease colonizes in the body there are three stages

 * Stage one (Early Localized Lyme disease):** Patients who have this stage of Lyme disease are asymptomatic. Their innate immune system is successfully fighting off the pathogen.


 * Stage two (Early Disseminated Lyme disease):** The disease spreads throughout the body. An adaptive immune response is added but often it is this immune response that causes the symptoms. The outer protein layer of the //B burgdorferi// has epitopes that confuse antibodies and lead to autoimmune related symptoms. The bacteria can also force host cells to release damaging toxins throughout the body and disrupt all sorts of brain functions.


 * Stage three** **(Late Disseminated Lyme disease)**
 * A more dire form of stage two. The bacteria has spread throughout the body and can cause long term, irreversible damage.