Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum subspecies pallidum. The signs and symptoms depend on the stage it presents: primary, secondary, latent or tertiary. The primary stage classically presents with a single chancre though there may be multiple sores. In secondary syphilis, a diffuse rash occurs, which frequently involves the palms of the hands and soles of the feet. There may also be sores in the mouth or vagina. Latent syphilis has no symptoms and can last years. In tertiary syphilis, there are gummas, neurological problems, or heart symptoms. Syphilis has been known as "the great imitator" because it may cause symptoms similar to many other diseases.
Treponema pallidum, formerly known as Spirochaeta pallida, is a microaerophilic, gram-negative, spirochaete bacterium with subspecies that cause the diseases syphilis, bejel, and yaws. It is known to be transmitted only among humans and baboons. It is a helically coiled microorganism usually 6–15 μm long and 0.1–0.2 μm wide. T. pallidum's lack of both a tricarboxylic acid cycle and processes for oxidative phosphorylation results in minimal metabolic activity. The treponemes have cytoplasmic and outer membranes. Using light microscopy, treponemes are visible only by using dark-field illumination. T. pallidum consists of three subspecies, T. p. pallidum, T. p. endemicum, and T. p. pertenue, each of which has a distinct associated disease. The ability of T. pallidum to avoid host immune defenses has allowed for stealth pathogenicity. The unique outer membrane structure and minimal expression of surface proteins of T. pallidum has made vaccine development difficult. Treponema pallidum can be treated with antibiotics such as penicillin.
Yaws is a tropical infection of the skin, bones, and joints caused by the spirochete bacterium Treponema pallidum pertenue. The disease begins with a round, hard swelling of the skin, 2 to 5 cm in diameter. The center may break open and form an ulcer. This initial skin lesion typically heals after 3–6 months. After weeks to years, joints and bones may become painful, fatigue may develop, and new skin lesions may appear. The skin of the palms of the hands and the soles of the feet may become thick and break open. The bones may become misshapen. After 5 years or more, large areas of skin may die, leaving scars.
The Wassermann test or Wassermann reaction (WR) is an antibody test for syphilis, named after the bacteriologist August Paul von Wassermann, based on complement fixation. It was the first blood test for syphilis and the first in the nontreponemal test (NTT) category. Newer NTTs, such as the RPR and VDRL tests, have mostly replaced it. During the mid-20th century, in many jurisdictions, including most US states, applicants for a marriage license were required by law to undergo a Wassermann test.
The Venereal Disease Research Laboratory test (VDRL) is a blood test for syphilis and related non-venereal treponematoses that was developed by the eponymous US laboratory. The VDRL test is used to screen for syphilis, whereas other, more specific tests are used to diagnose the disease.
In immunology, seroconversion is the development of specific antibodies in the blood serum as a result of infection or immunization, including vaccination. During infection or immunization, antigens enter the blood, and the immune system begins to produce antibodies in response. Before seroconversion, the antigen itself may or may not be detectable, but the antibody is absent. During seroconversion, the antibody is present but not yet detectable. After seroconversion, the antibody is detectable by standard techniques and remains detectable unless the individual seroreverts, in a phenomenon called seroreversion, or loss of antibody detectability, which can occur due to weakening of the immune system or decreasing antibody concentrations over time. Seroconversion refers the production of specific antibodies against specific antigens, meaning that a single infection could cause multiple waves of seroconversion against different antigens. Similarly, a single antigen could cause multiple waves of seroconversion with different classes of antibodies. For example, most antigens prompt seroconversion for the IgM class of antibodies first, and subsequently the IgG class.
Congenital syphilis is syphilis that occurs when a mother with untreated syphilis passes the infection to her baby during pregnancy or at birth. It may present in the fetus, infant, or later. Clinical features vary and differ between early onset, that is presentation before 2-years of age, and late onset, presentation after age 2-years. Infection in the unborn baby may present as poor growth, non-immune hydrops leading to premature birth or loss of the baby, or no signs. Affected newborns mostly initially have no clinical signs. They may be small and irritable. Characteristic features include a rash, fever, large liver and spleen, a runny and congested nose, and inflammation around bone or cartilage. There may be jaundice, large glands, pneumonia, meningitis, warty bumps on genitals, deafness or blindness. Untreated babies that survive the early phase may develop skeletal deformities including deformity of the nose, lower legs, forehead, collar bone, jaw, and cheek bone. There may be a perforated or high arched palate, and recurrent joint disease. Other late signs include linear perioral tears, intellectual disability, hydrocephalus, and juvenile general paresis. Seizures and cranial nerve palsies may first occur in both early and late phases. Eighth nerve palsy, interstitial keratitis and small notched teeth may appear individually or together; known as Hutchinson's triad.
Serology is the scientific study of serum and other body fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum. Such antibodies are typically formed in response to an infection, against other foreign proteins, or to one's own proteins. In either case, the procedure is simple.
Pinta is a human skin disease caused by infection with the spirochete Treponema carateum, which is morphologically and serologically indistinguishable from the bacterium that causes syphilis and bejel. The disease was previously known to be endemic to Mexico, Central America, and South America; it may have been eradicated since, with the latest case occurring in Brazil in 2020.
Bejel, or endemic syphilis, is a chronic skin and tissue disease caused by infection by the endemicum subspecies of the spirochete Treponema pallidum. Bejel is one of the "endemic treponematoses", a group that also includes yaws and pinta. Typically, endemic trepanematoses begin with localized lesions on the skin or mucous membranes. Pinta is limited to affecting the skin, whereas bejel and yaws are considered to be invasive because they can also cause disease in bone and other internal tissues.
Neurosyphilis is the infection of the central nervous system in a patient with syphilis. In the era of modern antibiotics, the majority of neurosyphilis cases have been reported in HIV-infected patients. Meningitis is the most common neurological presentation in early syphilis. Tertiary syphilis symptoms are exclusively neurosyphilis, though neurosyphilis may occur at any stage of infection.
Paroxysmal cold hemoglobinuria (PCH) or Donath–Landsteiner hemolytic anemia (DLHA) is an autoimmune hemolytic anemia featured by complement-mediated intravascular hemolysis after cold exposure. It can present as an acute non-recurrent postinfectious event in children, or chronic relapsing episodes in adults with hematological malignancies or tertiary syphilis. Described by Julius Donath (1870–1950) and Karl Landsteiner (1868–1943) in 1904, PCH is one of the first clinical entities recognized as an autoimmune disorder.
Selective immunoglobulin A (IgA) deficiency (SIgAD) is a kind of immunodeficiency, a type of hypogammaglobulinemia. People with this deficiency lack immunoglobulin A (IgA), a type of antibody that protects against infections of the mucous membranes lining the mouth, airways, and digestive tract. It is defined as an undetectable serum IgA level in the presence of normal serum levels of IgG and IgM, in persons older than 4 years. It is the most common of the primary antibody deficiencies. Most such persons remain healthy throughout their lives and are never diagnosed.
The fluorescent treponemal antibody absorption (FTA-ABS) test is a diagnostic test for syphilis. Using antibodies specific for the Treponema pallidum species, such tests would be assumed to be more specific than non-treponemal testing such as VDRL but have been shown repeatedly to be sensitive but not specific for the diagnosis of neurosyphilis in cerebrospinal fluid (CSF). In addition, FTA-ABS turns positive earlier and remains positive longer than VDRL. Other treponemes, such as T. pertenue, may also produce a positive FTA-ABS. The ABS suffix refers particularly to a processing step used to remove nonspecific antispirochetal antibodies present in normal serum.
Anti-cardiolipin antibodies (ACA) are antibodies often directed against cardiolipin and found in several diseases, including syphilis, antiphospholipid syndrome, livedoid vasculitis, vertebrobasilar insufficiency, Behçet's syndrome, idiopathic spontaneous abortion, and systemic lupus erythematosus (SLE). They are a form of anti-mitochondrial antibody. In SLE, anti-DNA antibodies and anti-cardiolipin antibodies may be present individually or together; the two types of antibodies act independently. This is in contrast to rheumatoid arthritis with systemic sclerosis (scleroderma) because anti-cardiolipin antibodies are present in both conditions, and therefore may tie the two conditions together.
A nontreponemal test (NTT) is a blood test for diagnosis of infection with syphilis. Nontreponemal tests are an indirect method in that they detect biomarkers that are released during cellular damage that occurs from the syphilis spirochete. In contrast, treponemal tests look for antibodies that are a direct result of the infection thus, anti-treponeme IgG, IgM and to a lesser degree IgA. Nontreponemal tests are screening tests, very rapid and relatively simple, but need to be confirmed by treponemal tests. Centers for Disease Control and Prevention (CDC)-approved standard tests include the VDRL test, the rapid plasma reagin (RPR) test, the unheated serum reagin (USR) test, and the toluidine red unheated serum test (TRUST). These have mostly replaced the first nontreponemal test, the Wassermann test.
The Treponema pallidum particle agglutination assay is an indirect agglutination assay used for detection and titration of antibodies against the causative agent of syphilis, Treponema pallidum subspecies pallidum. It also detects other treponematoses.
The first recorded outbreak of syphilis in Europe occurred in 1494/1495 in Naples, Italy, during a French invasion. Because it was spread geographically by French troops returning from that campaign, the disease was known as "French disease", and it was not until 1530 that the term "syphilis" was first applied by the Italian physician and poet Girolamo Fracastoro. The causative organism, Treponema pallidum, was first identified by Fritz Schaudinn and Erich Hoffmann in 1905 at the Charité Clinic in Berlin. The first effective treatment, Salvarsan, was developed in 1910 by Sahachiro Hata in the laboratory of Paul Ehrlich. It was followed by the introduction of penicillin in 1943.
Meningeal syphilis is a chronic form of syphilis infection that affects the central nervous system. Treponema pallidum, a spirochate bacterium, is the main cause of syphilis, which spreads drastically throughout the body and can infect all its systems if not treated appropriately. Treponema pallidum is the main cause of the onset of meningeal syphilis and other treponemal diseases, and it consists of a cytoplasmic and outer membrane that can cause a diverse array of diseases in the central nervous system and brain.
Blood compatibility testing is conducted in a medical laboratory to identify potential incompatibilities between blood group systems in blood transfusion. It is also used to diagnose and prevent some complications of pregnancy that can occur when the baby has a different blood group from the mother. Blood compatibility testing includes blood typing, which detects the antigens on red blood cells that determine a person's blood type; testing for unexpected antibodies against blood group antigens ; and, in the case of blood transfusions, mixing the recipient's plasma with the donor's red blood cells to detect incompatibilities (crossmatching). Routine blood typing involves determining the ABO and RhD type, and involves both identification of ABO antigens on red blood cells and identification of ABO antibodies in the plasma. Other blood group antigens may be tested for in specific clinical situations.
