Syphilis: A contagious venereal disease caused by the spirochete TREPONEMA PALLIDUM.Syphilis, Congenital: Syphilis acquired in utero and manifested by any of several characteristic tooth (Hutchinson's teeth) or bone malformations and by active mucocutaneous syphilis at birth or shortly thereafter. Ocular and neurologic changes may also occur.Syphilis Serodiagnosis: Serologic tests for syphilis.Syphilis, Cutaneous: Cutaneous lesions arising from infection with Treponema pallidum. In the primary stage, 18-21 days following infection, one or more chancres appear. If untreated, the subsequent stages of the disease appear as syphilids. These eruptions are superficial, nondestructive, exanthematic, transient, macular roseolas that may later be maculopapular or papular polymorphous or scaly, pustular, pigmented eruptions.(Arnold, Odom, and James, Andrew's Diseases of the Skin, 8th ed, p409)Treponema pallidum: The causative agent of venereal and non-venereal syphilis as well as yaws.Syphilis, LatentNeurosyphilis: Infections of the central nervous system caused by TREPONEMA PALLIDUM which present with a variety of clinical syndromes. The initial phase of infection usually causes a mild or asymptomatic meningeal reaction. The meningovascular form may present acutely as BRAIN INFARCTION. The infection may also remain subclinical for several years. Late syndromes include general paresis; TABES DORSALIS; meningeal syphilis; syphilitic OPTIC ATROPHY; and spinal syphilis. General paresis is characterized by progressive DEMENTIA; DYSARTHRIA; TREMOR; MYOCLONUS; SEIZURES; and Argyll-Robertson pupils. (Adams et al., Principles of Neurology, 6th ed, pp722-8)Reagins: Antibodies, especially IGE, that bind to tissue of the same species so that ANTIGENS induce release of HISTAMINE and other vasoactive agents. HYPERSENSITIVITY is the clinical manifestation.Syphilis, Cardiovascular: Cardiovascular manifestations of SYPHILIS, an infection of TREPONEMA PALLIDUM. In the late stage of syphilis, sometimes 20-30 years after the initial infection, damages are often seen in the blood vessels including the AORTA and the AORTIC VALVE. Clinical signs include syphilitic aortitis, aortic insufficiency, or aortic ANEURYSM.Yaws: A systemic non-venereal infection of the tropics caused by TREPONEMA PALLIDUM subspecies pertenue.Antitreponemal Agents: Agents used to treat infections with bacteria of the genus TREPONEMA. This includes SYPHILIS & YAWS.Pregnancy Complications, Infectious: The co-occurrence of pregnancy and an INFECTION. The infection may precede or follow FERTILIZATION.Chancre: The primary sore of syphilis, a painless indurated, eroded papule, occurring at the site of entry of the infection.Sexually Transmitted Diseases: Diseases due to or propagated by sexual contact.Homosexuality, Male: Sexual attraction or relationship between males.Penicillin G Procaine: Semisynthetic antibiotic prepared by combining penicillin G with PROCAINE.Gonorrhea: Acute infectious disease characterized by primary invasion of the urogenital tract. The etiologic agent, NEISSERIA GONORRHOEAE, was isolated by Neisser in 1879.Treponema Immobilization Test: Syphilis serodiagnosis employing as the antigen Treponema pallidum obtained from rabbit syphilis orchitis. Treponemes are kept alive for a few hours in a special medium. When syphilitic serum and complement are added and incubated, the treponemes are immobilized, i.e., stop moving.Fluorescent Treponemal Antibody-Absorption Test: Serologic assay that detects antibodies to Treponema pallidum, the etiologic agent of syphilis. After diluting the patient's serum to remove non-specific antibodies, the serum is mixed on a glass slide with Nichol's strain of Treponema pallidum. An antigen-antibody reaction occurs if the test is positive and the bound antibodies are detected with fluoresceinated antihuman gamma-globulin antibody.HIV Infections: Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Hemagglutination Tests: Sensitive tests to measure certain antigens, antibodies, or viruses, using their ability to agglutinate certain erythrocytes. (From Stedman, 26th ed)Prostitution: The practice of indulging in sexual relations for money.Sex Workers: People who engage in occupational sexual behavior in exchange for economic rewards or other extrinsic considerations.Periostitis: Inflammation of the periosteum. The condition is generally chronic, and is marked by tenderness and swelling of the bone and an aching pain. Acute periostitis is due to infection, is characterized by diffuse suppuration, severe pain, and constitutional symptoms, and usually results in necrosis. (Dorland, 27th ed)Treponemal Infections: Infections with bacteria of the genus TREPONEMA.Ulcer: A lesion on the surface of the skin or a mucous surface, produced by the sloughing of inflammatory necrotic tissue.Flocculation Tests: Precipitin tests which occur over a narrow range of antigen-antibody ratio, due chiefly to peculiarities of the antibody (precipitin). (From Stedman, 26th ed)Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Prenatal Care: Care provided the pregnant woman in order to prevent complications, and decrease the incidence of maternal and prenatal mortality.Tabes Dorsalis: Parenchymatous NEUROSYPHILIS marked by slowly progressive degeneration of the posterior columns, posterior roots, and ganglia of the spinal cord. The condition tends to present 15 to 20 years after the initial infection and is characterized by lightening-like pains in the lower extremities, URINARY INCONTINENCE; ATAXIA; severely impaired position and vibratory sense, abnormal gait (see GAIT DISORDERS, NEUROLOGIC), OPTIC ATROPHY; Argyll-Robertson pupils, hypotonia, hyperreflexia, and trophic joint degeneration (Charcot's Joint; see ARTHROPATHY, NEUROGENIC). (From Adams et al., Principles of Neurology, 6th ed, p726)History, 15th Century: Time period from 1401 through 1500 of the common era.Mass Screening: Organized periodic procedures performed on large groups of people for the purpose of detecting disease.Serologic Tests: Diagnostic procedures involving immunoglobulin reactions.AlabamaPinta: An infectious disease of the skin caused by Treponema carateum that occurs only in the western hemisphere. Age of onset is between 10 and 20 years of age. This condition is characterized by marked changes in the skin color and is believed to be transmitted by direct person-to-person contact.Sexual Behavior: Sexual activities of humans.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Homosexuality: The sexual attraction or relationship between members of the same SEX.Sexually Transmitted Diseases, Bacterial: Bacterial diseases transmitted or propagated by sexual conduct.United States Public Health Service: A constituent organization of the DEPARTMENT OF HEALTH AND HUMAN SERVICES concerned with protecting and improving the health of the nation.Coinfection: Simultaneous infection of a host organism by two or more pathogens. In virology, coinfection commonly refers to simultaneous infection of a single cell by two or more different viruses.China: A country spanning from central Asia to the Pacific Ocean.Penicillins: A group of antibiotics that contain 6-aminopenicillanic acid with a side chain attached to the 6-amino group. The penicillin nucleus is the chief structural requirement for biological activity. The side-chain structure determines many of the antibacterial and pharmacological characteristics. (Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p1065)Treponema: A genus of microorganisms of the order SPIROCHAETALES, many of which are pathogenic and parasitic for man and animals.Seroepidemiologic Studies: EPIDEMIOLOGIC STUDIES based on the detection through serological testing of characteristic change in the serum level of specific ANTIBODIES. Latent subclinical infections and carrier states can thus be detected in addition to clinically overt cases.