What Is Lyme Disease?
Lyme disease is an infection caused by bacteria called Borrelia burgdorferi (Bb).
How is it transmitted?
In the US, the bacteria are transmitted to people and animals by the bite of an infected blacklegged tick, Ixodes scapularis, commonly called the deer tick, and Ixodes pacificus (western black legged tick) in the West. Although other types of ticks such as the Dermancentor variabilis (american dog) and some insects have been shown to carry the Lyme bacteria, to date, transmission of Lyme through those vectors has not been proven.
The bacteria can also be passed through the placenta of a pregnant woman to the fetus—congenital transmission.
The DNA of the bacteria has been found in breast milk, but no transmission has been proven to date in humans.
The Lyme bacteria have been proven to survive blood banking conditions; however, to date, no transmission has been proven through blood transfusions in humans. Studies have shown transmission through this route in mice in the lab.
There is no proof to date that Lyme is sexually transmitted, although some preliminary studies have found PCR positives for the DNA of the Lyme bacteria in semen and in cervical tissue. These findings do not prove sexual transmission, but some physicians feel because the Lyme and syphilis spirochete (bacteria) are similar, Lyme may be sexually transmitted.
Lyme disease is found in approximately 65 countries world wide, although different types of ticks and different strains of bacteria may be involved.
Where can Lyme disease be found in the body?
Lyme is a multi-systemic disease, and the Lyme disease bacterium, Borrelia burgdorferi (Bb), may be found in many different organs, although it is often difficult to test for and to culture. Here is a picture which shows Bb in the human colon.
Borrelia burgdorferi (Lyme disease bacterium) in the Human Colon
A Lyme disease patient's colon biopsy specimen. The patient had abdominal pain and blood in the stool (Dieterle stain-magnification x522)
Photo Courtesy of Martin Fried, MD