False positives can also occur with lymphoma, tuberculosis, malaria, endocarditis, connective tissue disease, and pregnancy.Because of the possibility of false positives with nontreponemal tests, confirmation is required with a treponemal test, such as treponemal pallidum particle agglutination (TPHA) or fluorescent treponemal antibody absorption test (FTA-Abs). Treponemal antibody tests usually become positive two to five weeks after the initial infection. Neurosyphilis is diagnosed by finding high numbers of leukocytes (predominately lymphocytes) and high protein levels in the cerebrospinal fluid in the setting of a known syphilis infection. Direct testing
Dark field microscopy of serous fluid from a chancre may be used to make an immediate diagnosis. Hospitals do not always have equipment or experienced staff members, and testing must be done within 10 minutes of acquiring the sample. Two other tests can be carried out on a sample from the chancre: direct fluorescent antibody (DFA) and polymerase chain reaction (PCR) tests. DFA uses antibodies tagged with fluorescein, which attach to specific syphilis proteins, while PCR uses techniques to detect the presence of specific syphilis genes. These tests are not as time-sensitive, as they do not require living bacteria to make the diagnosis. Prevention
Vaccine
As of 2018, there is no vaccine effective for prevention. Several vaccines based on treponemal proteins reduce lesion development in an animal model but research continues. Sex
Condom use reduces the likelihood of transmission during sex, but does not eliminate the risk.
It is caused by cytokines released by the immune system in response to lipoproteins released from rupturing syphilis bacteria. Pregnancy
Penicillin is an effective treatment for syphilis in pregnancy but there is no agreement on which dose or route of delivery is most effective. Epidemiology
In 2012, about 0.5% of adults were infected with syphilis, with 6 million new cases. In 1999, it is believed to have infected 12 million additional people, with greater than 90% of cases in the developing world. It affects between 700,000 and 1.6 million pregnancies a year, resulting in spontaneous abortions, stillbirths, and congenital syphilis. During 2015, it caused about 107,000 deaths, down from 202,000 in 1990. In sub-Saharan Africa, syphilis contributes to approximately 20% of perinatal deaths. Rates are proportionally higher among intravenous drug users, those who are infected with HIV, and men who have sex with men. In the United States about 55,400 people are newly infected each year. In the United States as of 2020, rates of syphilis have increased by more than threefold; in 2018 approximately 86% of all cases of syphilis in the United States were in men. African Americans accounted for almost half of all cases in 2010. As of 2014, syphilis infections continue to increase in the United States.Syphilis was very common in Europe during the 18th and 19th centuries. Flaubert found it universal among nineteenth-century Egyptian prostitutes. In the developed world during the early 20th century, infections declined rapidly with the widespread use of antibiotics, until the 1980s and 1990s.