When one thinks of a tick, they typically think of a pesky bug they sometimes find on themselves after a day of hiking, or something they occasionally pull off one of their pets. However, these seemingly innocuous pests can carry and transmit a disease known as Lyme Disease. Lyme disease is transmitted through the bite of a black-legged, or deer tick. It is caused by the bacteria Borrelia burgdorferi. The symptoms are similar to those of the flu. Lyme disease infects around 300,000 people per year, making it a relatively common disease. Boys, aged 5-9 are the most common cases, however, it can affect everyone, especially children and people who work outside often.Lyme disease is an ancient disease. In fact, an autopsy performed on a 5,300 year old mummy found that the bacteria that causes Lyme Disease was present. Alfred Buchwald described the rash that accompanies Lyme Disease, called erythema migrans, more than 130 years ago. Although this disease is old, it was only recognized in the United States in the 1960’s and 70’s. The bacteria which causes Lyme Disease was not classified until the 1980’s. The 1970’s is when Lyme Disease seems to have become prevalent. A group of children and some adults from, mainly, Lyme, Connecticut developed mysterious symptoms. These included swollen knees, paralysis, skin rashes, headaches, and severe chronic fatigue. No one could figure out what was causing these symptoms, so the patients were undiagnosed and untreated. Because of the severeness of these symptoms, and the fact that no one knew what was causing them, two mothers became extremely persistent. They took notes, conducted research, and contacted scientists. Because of their persistence, scientists and other members of the medical community began to look into the group. They found that the children all had a skin rash, which was then followed by conditions similar arthritis. Another, surprising, piece of information was that they all remembered being bitten by a tick. By the mid-1970’s researchers called this newfound disease Lyme, based on its city of origin. The 1980’s marked the discovery of the bacteria. Willy Burgdorfer was studying Rocky Mountain Fever, and began to study Lyme disease. The common link was that both are caused by tick bites. Burgdorfer discovered that a type of bacteria, known as a spirochete, was causing Lyme, which is carried by ticks. The spirochete was named Borrelia burgdorferi in his honor.Mode of Transmission and How Pathogen Enters HostLyme disease is transmitted through a tick bite. The tick must be a black legged, or deer tick, and it must be infected with Borrelia burgdorferi. Other ticks, such as the lone star tick, the American dog tick, and the brown dog tick, cannot transmit Lyme disease. The infected tick will attach to the body, usually the groin, armpits, or scalp, because of the warmth, protection, and moisture. The tick, in most scenarios, must be attached for 36-48 hours in order for the bacteria to be transmitted into the body. A tick bite is a somewhat complicated process, for a small insect. The ticks mouth part consists of three pieces. The first and center piece is long and swordlike, and is called the hypostome. The hypostome has many rows of curved spines along the edges and underside. There is also a groove in the middle, which channels blood into the tick, and saliva out of the tick into the host. Next, on top of the hypostome is two chelicerae. They are long rods which end in hooked teeth. They are able to move, and move to just beyond the hypostome tip, or shrink to around half that length. They are also able to move around 45 degrees outward. To start the attachment process, first the tick gently waves its chelicerae over the hosts skin. This scrapes and punctures the host, because each chelicerae ends in a sharp tooth. To break into the skin, the tick flexes the tips of the chelicerae. They move separately at first and then move together. The teeth at the end catch on the hosts skin, and after several flexions, they are both embedded into the skin. After this, the tick contracts the chelicerae and flexes the tips at the same time. This causes the hypostome to essentially stab the skin. The chelicerae repeat this movement around 6 times, each time pushing the hypostome deeper and deeper, until it is firmly in place. It’s because of this specialized biting that Lyme disease exists. If a tick did not have such a strong way of attaching to its host, the bacteria would never be able to enter the body. The bacteria travels from the ticks stomach, into its bloodstream, then is salivary glands, and ultimately, into the host. If the tick was not firmly embedded into the skin, the bacteria would not have time to travel.Ticks get this bacteria from feeding on rodents, such as mice, which are readily found in forests. These rodents, and some birds carry the infection and pass the infection from their blood into the tick, where the bacteria goes into their digestive organs.Nature of Pathogen/Biology of PathogenBorrelia burgdorferi is a bacteria, which is a type of pathogen. A pathogen is defined as “a biological agent that causes disease or illness to its host.” They are microscopic and are adapted to infect, bypass, reproduce, and escape. They infect the host, bypass their immune system, which protects from foreign invasions, reproduce inside the body, and escape, to pass the disease onto another host. Borrelia burgdorferi is a specific type of bacteria, known as a spirochete. A spirochete is long and thin, and most closely resembles a spring. They are unique because they have axial filaments, or basically internal flagella. They are embedded in the cell wall and allow the bacteria in move in a corkscrew motion.