Syphilis is a complex sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It is highly infectious and shows symptoms in three stages. Bacteria which enters the body through mucous membranes during sexual intercourse may be found on the penis, vagina, vulva and in the mouth or anus depending up on the site of infection. Bacteria can also be transmitted from an infected mother to her child during child birth. This infection can be effectively treated and later stages can be avoided if diagnosed early and treatment is given promptly and routinely.

Symptoms
In the first stage, an infection causes an ulcer at the site of infection; with in a short time the Lymph nodes around the infection and then all over the body enlarges and harden. The ulcer can appear within 10 days to three months after exposure, but it generally appears within two to six week and these symptoms persists for several weeks. If adequate treatment is not administered, the infection progresses to the secondary stage.
Secondary symptoms appear about two months after initial infection and may overlap with the first stage; these include fever, pains, enlarged lymph nodes and a rash usually found on the chest, on the palms of the hands and on the bottoms of the feet. The rash often appears as rough, red or reddish brown spots. In addition symptoms may include sore throat, patchy hair loss, headaches, weight loss, muscle aches, and tiredness. An infected person who has not been treated can easily infect sexual partners during the first two stages, which usually last one to two years. In the second stage infection can also spread through the broken skin of an infected sore by any physical contact either sexual or non-sexual.

The third and final stage may not appear until many months or years after infection, in untreated people. It comprises the infection of numerous tumour-like masses throughout the body in skin, muscle, bone, brain, spinal cord and the other organ such as the liver, stomach etc.

In infected infants, symptoms may include skin sores, rashes, fever, weakened or hoarse crying sounds, swollen liver and spleen, yellowish skin (jaundice), anemia, and various deformities.

Adverse effects
Syphilis increases the risk of transmitting and acquiring the human immunodeficiency virus (HIV) that causes AIDS. The third stage can cause serious damage to the heart, brain or spinal cord resulting in blindness, paralysis, numbness, mental disability and even lead to death.
In addition, a pregnant woman with syphilis can pass the bacterium to her unborn child, who may be born with serious mental and physical problems as a result of this infection. Sometimes symptoms in infants go undetected and as they grow older they may develop the symptoms of late-stage syphilis including damage to their bones, teeth, eyes, ears, and brain. In pregnancy if the infection is left untreated, it can even cause still birth or neonatal death.

Test
Diagnosis is confirmed by taking a swab from the infectious sores and by examining using dark field microscopy in a lab. If syphilis bacteria are present in the sore, they will show up with a characteristic appearance. A blood test is another way of testing for syphilis. Shortly after infection, the body produces syphilis antibodies that can be detected by the blood test. As blood tests may show false results, repeated tests are sometimes necessary to confirm the diagnosis. A low level of antibodies will stay in the blood for months or years even after the disease has been successfully treated. Follow up tests are carried out to ensure success of the treatment. In the late stage of syphilis, a lumbar puncture (spinal tap) is done to check for infection of the nervous system.

Treatment
Treatment is through administration of penicillin, usually by injection, which is normally very successful. Single dose of penicillin can cure persons who has had syphilis for less than a year but larger doses may be needed for others. The treatment is successful in stopping further damage, but it will not repair any damage already done.
Persons who receive syphilis treatment must abstain from sexual contact with new partners until the syphilis sores are completely healed. Because untreated syphilis in a pregnant woman can infect and possibly kill her developing baby, every pregnant woman should have a blood test for syphilis.