Causes and symptoms: Syphilis is among the most serious of sexually transmitted diseases. The disease is caused by a microorganism called treponema pallidum. The bacterium gains entrance to the body through minor cuts or abrasions in the skin or mucous membranes, most often during sexual intercourse. The disease also may be transmitted from mother to child before or during birth. 

The disease can be classified into three stages. In the first stage (primary syphilis), two to twelve weeks after exposure, painless oval-shaped sores appear on the genitals, rectum or mouth. Lymph nodes near the groin or in the neck may be swollen as well. These sores disappear on their own in two to four weeks time. 

If this stage goes untreated, the disease moves on to the second stage (secondary syphilis) one to six months later when the organism spreads into the bloodstream. This stage is characterized by symptoms like red rash, flu-like symptoms, such as headache, fever, fatigue, loss of appetite and pain in bones and joints. These symptoms also subside by themselves without treatment. The disease now becomes latent, but the bacteria remain in the body.  

The third and most serious stage (tertiary syphilis) can begin any time from one year to several decades later. Tertiary syphilis can lead to irreversible damage to the liver, bones, brain, heart and other organs. 

Diagnosis: Syphilis is diagnosed through blood tests. However, the results of a blood test may not show up as positive immediately after the person has been infected. Thus, it is advisable to repeat the test around six weeks after a person thinks that he has become infected. The doctor can also take a scraping from the surface of the lesion, and examine it under a special "darkfield" microscope to detect the organism itself.

Treatment: Penicillin is effective in treating the primary and secondary stages of this disease. The drug is usually administered by injection, as oral forms may not be as effective. However, if the disease progresses to the third stage, it can cause irreversible damage to the heart and nervous system. A person infected with syphilis should also have regular follow-up blood tests for atleast a year after treatment. In all stages of syphilis, proper treatment will cure the disease, but in late syphilis, damage already done to body organs cannot be reversed.

Complications: Syphilis increases the risk of transmitting and acquiring the human immunodeficiency virus (HIV) that causes AIDS. A person's joints may be affected, resulting in arthritis. Cardiovascular syphilis can cause heart disease. Neurosyphilis, can result in paralysis, blindness, senility, psychiatric problems or loss of sensation in the legs. 

If a pregnant woman transmits the disease to her baby, it could result in a stillbirth. Babies born with syphilis may develop symptoms two weeks to three months after birth. These symptoms may include skin sores, rashes, fever, weakened or hoarse crying sounds, swollen liver and spleen, yellowish skin (jaundice), anemia, and various deformities. Care must be taken in handling an infant with congenital syphilis because the moist sores are infectious.

Prevention: The open sores of syphilis may be visible and infectious during the active stages of infection. Any contact with these infectious sores and other infected tissues and body fluids must be avoided to prevent spread of the disease. Screening and treatment of infected individuals in the early stages of the disease will help prevent the disease from advancing to a more serious stage. Testing and treatment early in pregnancy is the best way to prevent syphilis in infants and should be a routine part of prenatal care. Sexually active individuals should use condoms during sexual intercourse.