Write an article on Syphilis. It needs to be at least 1000 words. Syphilis is a bacterial infection that is primarily spread through sexual contact but can also be transmitted from mother to fetus while in the womb or during birth resulting to congenital syphilis. It usually starts out as a painless sore that can be found on the genital area, rectum, or the mouth. Without treatment, syphilis can result to irreversible damage to the brain, nerves or body tissues. This disease has many times been known as “the great imitator” because its many signs and symptoms are identical from those of other diseases. Sir William Osler stated that “The physician who knows syphilis knows medicine.” (Rudkin and Blasko, 2011) The causative agent for syphilis is an organism known as Treponema pallidum. This is a gram-negative spirochete and is a parasite. It ranges from 6-20 um, while its diameter ranges from 18-20 um. It is a microaerophilic agent and requires low concentrations of oxygen. This bacterium is corkscrew shaped and has no animal or environmental reservoirs. This organism is usually acquired and spread by close sexual contact, entering the host through openings in squamous or columnar epithelium. It gains access to the blood and lymph systems through mucus membranes. (Dandelin, 2009) Treponema pallidum has four known subspecies which cause different illnesses. The first is Treponema pallidum pallidum, which causes syphilis. The second one is Treponema endemicum, which causes endemic syphilis. The third is Treponema pallidum carateum, which has been known to cause pinta, which is a human skin disease endemic commonly found in Mexico, Central America and South America. The last sub specie is Treponema palidum pertenue which causes yaws. Yaws is a long-term infection that mainly affects the skin, bones and joints. (Doran and Nowadly, 2010) Humans are the only known reservoir for T. pallidum. The portal of entry into the host is mucus membranes. It is transmitted almost always through sexual contact with an infected partner. After the spirochetes pass the barrier, they are carried through the bloodstream to every organ of the body. About three to four weeks after the bacteria has gained entrance into the new host, a lesion will form at the point of contact, which is known as a chancre. It usually presents as a firm, painless, skin ulceration with a diameter of 0.3-3 cm in size. This lesion will refuse to go away for about five weeks then eventually will heal spontaneously. This is known as the primary stage. (Brown, 2011) About six weeks later, a localized cutaneous eruption may appear. This is the secondary stage, and there may be many different manifestations. The main characteristics of this stage are skin rash and mucus membrane lesions. There may be other symptoms such as fever, sore throat, and weight loss, feelings of body malaise, hair loss and even headache. At this stage, the infection spreads to the rest of the body. The rash may spread to the feet, the back, or the hands. Sometimes, the rashes that occur with syphilis are so small that they can go unnoticed. One of the dangers of this disease is that the signs and symptoms will resolve with or without treatment, which may lead one to think that the problem is gone. but without treatment, the infection will progress to the latent and possibly late stages of disease.