Chlamydial infection of the  cervix  (neck of the womb) is a sexually transmitted infection which has  no symptoms  for  around 70% of women infected. The infection can be passed through vaginal, anal, oral, or manual sex. Of those who have an asymptomatic infection that is not detected by their doctor, approximately half will develop  pelvic inflammatory disease  (PID), a generic term for infection of the  uterus ,  fallopian tubes , and/or  ovaries . PID can cause scarring inside the  reproductive organs , which can later cause serious complications, including chronic  pelvic  pain, difficulty becoming pregnant,  ectopic (tubal) pregnancy , and other dangerous complications of pregnancy. [ 14 ]


Chlamydia is known as the "silent epidemic", as at least 70% of genital  C. trachomatis  infections in women (and 50% in men) are asymptomatic at the time of diagnosis, [ 15 ]  and can linger for months or years before being discovered. Signs and symptoms may include abnormal  vaginal bleeding  or discharge, abdominal pain,  painful sexual intercourse ,  fever ,  painful urination  or the urge to urinate more often than usual ( urinary urgency ). [ 14 ]


For sexually active women who are not pregnant, screening is recommended in those under 25 and others at risk of infection. [ 16 ]  Risk factors include a history of chlamydial or other sexually transmitted infection, new or multiple sexual partners, and inconsistent  condom  use. [ 17 ]  Guidelines recommend all women attending for  emergency contraceptive  are offered chlamydia testing, with studies showing up to 9% of women aged under 25 years had chlamydia. [ 18 ]


In men, those with a chlamydial infection show symptoms of infectious  inflammation of the urethra  in about 50% of cases. [ 15 ]  Symptoms that may occur include: a painful or burning sensation when urinating, an unusual discharge from the  penis ,  testicular  pain or swelling, or fever. If left untreated, chlamydia in men can spread to the testicles causing  epididymitis , which in rare cases can lead to  sterility  if not treated. [ 15 ]  Chlamydia is also a potential cause of  prostatic inflammation  in men, although the exact relevance in prostatitis is difficult to ascertain due to possible contamination from urethritis. [ 19 ]


Trachoma  is a chronic  conjunctivitis  caused by  Chlamydia trachomatis . [ 20 ]  It was once the leading cause of blindness worldwide, but its role diminished from 15% of blindness cases by trachoma in 1995 to 3.6% in 2002. [ 21 ] [ 22 ]  The infection can be spread from eye to eye by fingers, shared towels or cloths, coughing and sneezing and eye-seeking flies. [ 23 ]  Symptoms include  mucopurulent  ocular discharge, irritation, redness, and lid swelling. [ 20 ]  Newborns can also develop chlamydia eye infection through childbirth (see below). Using the SAFE strategy (acronym for surgery for  in-growing  or  in-turned  lashes,  antibiotics , facial cleanliness, and environmental improvements), the  World Health Organization  aimed (unsuccessfully) for the global elimination of trachoma by 2020 (GET 2020 initiative). [ 24 ] [ 25 ]  The updated World Health Assembly neglected tropical diseases road map (2021–2030) sets 2030 as the new timeline for global elimination. [ 26 ]


Chlamydia may also cause  reactive arthritis —the triad of arthritis, conjunctivitis and urethral inflammation—especially in young men. About 15,000 men develop reactive arthritis due to chlamydia infection each year in the U.S., and about 5,000 are permanently affected by it. It can occur in both sexes, though is more common in men. [ citation needed ]


As many as half of all infants born to mothers with chlamydia will be born with the disease. Chlamydia can affect infants by causing spontaneous abortion;  premature birth ;  conjunctivitis , which may lead to blindness; and  pneumonia . [ 27 ]  Conjunctivitis due to chlamydia typically occurs one week after birth (compared with chemical causes (within hours) or gonorrhea (2–5 days)). [ 28 ]


A different  serovar  of  Chlamydia trachomatis  is also the cause of  lymphogranuloma venereum , an infection of the  lymph nodes  and  lymphatics . It usually presents with  genital ulceration  and  swollen lymph nodes  in the groin, but it may also manifest as  rectal inflammation ,  fever  or swollen lymph nodes in other regions of the body. [ 29 ]


Chlamydia can be transmitted during vaginal, anal, oral, or manual sex or direct contact with infected tissue such as  conjunctiva . Chlamydia can also be passed from an infected mother to her baby during vaginal childbirth. [ 27 ]  It is assumed that the probability of becoming infected is proportionate to the number of bacteria one is exposed to. [ 30 ]


Chlamydia bacteria have the ability to establish long-term associations with host cells. When an infected host cell is starved for various nutrients such as  amino acids  (for example,  tryptophan ), [ 31 ]   iron , or  vitamins , this has a negative consequence for chlamydia bacteria since the organism is dependent on the host cell for these nutrients. Long-term cohort studies indicate that approximately 50% of those infected clear within a year, 80% within two years, and 90% within three years. [ 32 ]


The starved chlamydia bacteria can enter a persistent growth state where they stop  cell division  and become morphologically aberrant by increasing in size. [ 33 ]  Persistent organisms remain viable as they are capable of returning to a normal growth state once conditions in the host cell improve. [ 34 ]


There is debate as to whether persistence has relevance: some believe that persistent chlamydia bacteria are the cause of chronic chlamydial diseases. Some antibiotics such as  β-lactams  have been found to induce a persistent-like growth state. [ 35 ] [ 36 ]


The diagnosis of genital chlamydial infections evolved rapidly from the 1990s through 2006.  Nucleic acid amplification tests  (NAAT), such as  polymerase chain reaction  (PCR), transcription mediated amplification (TMA), and the DNA  strand displacement amplification  (SDA) now are the mainstays. NAAT for chlamydia may be performed on swab specimens  sampled  from the cervix (women) or urethra (men), on self-collected vaginal swabs, or on voided urine. [ 37 ]  NAAT has been estimated to have a  sensitivity  of approximately 90% and a  specificity  of approximately 99%, regardless of sampling from a cervical swab or by urine specimen. [ 38 ]  In women seeking treatment in a sexually transmitted infection clinic where a urine test is negative, a subsequent cervical swab has been estimated to be positive in approximately 2% of the time. [ 38 ]


At present, the NAATs have regulatory approval only for testing urogenital specimens, although rapidly evolving research indicates that they may give reliable results on rectal specimens.


Because of improved test accuracy, ease of specimen management, convenience in specimen management, and ease of screening sexually active men and women, the NAATs have largely replaced culture, the historic  gold standard  for chlamydia diagnosis, and the non-amplified probe tests. The latter test is relatively insensitive, successfully detecting only 60–80% of infections in asymptomatic women, and often giving falsely-positive results. Culture remains useful in selected circumstances and is currently the only assay approved for testing non-genital specimens. Other methods also exist including:  ligase chain reaction  (LCR), direct fluorescent antibody resting,  enzyme immunoassay , and cell culture. [ 39 ]


The swab sample for chlamydial infections does not show difference whether the sample was collected in home or in clinic in terms of numbers of patient treated. The implications in cured patients, reinfection, partner management, and safety are unknown. [ 40 ]


Rapid point-of-care tests are, as of 2020, not thought to be effective for diagnosing chlamydia in men of reproductive age and non-pregnant women because of high false-negative rates. [ 41 ]


Prevention is by  not having sex , the use of  condoms , or having sex with only one other person, who is not infected. [ 1 ]


For sexually active women who are not pregnant, screening is recommended in those under 25 and others at risk of infection. [ 16 ]  Risk factors include a history of chlamydial or other sexually transmitted infection, new or multiple sexual partners, and inconsistent  condom  use. [ 17 ]  For pregnant women, guidelines vary: screening women with age or other risk factors is recommended by the  U.S. Preventive Services Task Force  (USPSTF) (which recommends screening women under 25) and the  American Academy of Family Physicians  (which recommends screening women aged 25 or younger). The  American College of Obstetricians and Gynecologists  recommends screening all at risk, while the  Centers for Disease Control and Prevention  recommend universal screening of pregnant women. [ 16 ]  The USPSTF acknowledges that in some communities there may be other risk factors for infection, such as ethnicity. [ 16 ]  Evidence-based recommendations for screening initiation, intervals and termination are currently not possible. [ 16 ]  For men, the USPSTF concludes evidence is currently insufficient to determine if regular screening of men for chlamydia is beneficial. [ 17 ]  They recommend regular screening of men who are at increased risk for HIV or syphilis infection. [ 17 ]  A  Cochrane review  found that the effects of screening are uncertain in terms of chlamydia transmission but that screening probably reduces the risk of pelvic inflammatory disease in women. [ 42 ]


In the United Kingdom the  National Health Service (NHS)  aims to:


C. trachomatis  infection can be effectively cured with  antibiotics . Guidelines recommend  azithromycin ,  doxycycline ,  erythromycin , levofloxacin or  ofloxacin . [ 45 ]  In men, doxycycline (100 mg twice a day for 7 days) is probably more effective than azithromycin (1 g single dose) but evidence for the relative effectiveness of antibiotics in women is very uncertain. [ 46 ]  Agents recommended during pregnancy include erythromycin or  amoxicillin . [ 2 ] [ 47 ]


An option for treating sexual partners of those with chlamydia or  gonorrhea  includes  patient-delivered partner therapy  (PDT or PDPT), which is the practice of treating the sex partners of index cases by providing prescriptions or medications to the patient to take to his/her partner without the health care provider first examining the partner. [ 48 ]


Following treatment people should be tested again after three months to check for reinfection. [ 2 ]  Test of cure may be  false-positive  due to the limitations of NAAT in a bacterial (rather than a viral) context, since targeted genetic material may persist in the absence of viable organisms. [ 49 ]


Globally, as of 2015, sexually transmitted chlamydia affects approximately 61 million people. [ 11 ]  It is more common in women (3.8%) than men (2.5%). [ 51 ]  In 2015 it resulted in about 200 deaths. [ 6 ]


In the United States about 1.6 million cases were reported in 2016. [ 52 ]  The CDC estimates that if one includes unreported cases there are about 2.9 million each year. [ 52 ]  It affects around 2% of young people. [ 53 ]  Chlamydial infection is the most common bacterial sexually transmitted infection in the UK. [ 54 ]


Chlamydia causes more than 250,000 cases of epididymitis in the U.S. each year. Chlamydia causes 250,000 to 500,000 cases of PID every year in the United States. Women infected with chlamydia are up to five times more likely to become infected with HIV, if exposed. [ 27 ]


Chlamydia research [ 1 ]  is the systematic study of the organisms in the taxonomic group of bacteria  Chlamydiota  (formerly Chlamydiae), the diagnostic procedures [ 2 ]  to treat infections, the disease  chlamydia , infections caused by the organisms, the epidemiology of infection and the development of vaccines. The process of research can include the participation of many researchers who work in collaboration from separate organizations, governmental entities and universities. [ 3 ]


The  Centers for Disease Control and Prevention  (CDC) offers funding to research the  biology , physiology, epidemiology, vaccine development, and publish systematic reviews of Chlamydia species.  Other funding sources include the National Chlamydia Coalition. [ 4 ] [ 5 ]


Studies continue to determine the organism's genetic makeup. NIAID-supported scientists have determined the complete genome (genetic blueprint) for C. trachomatis. [ 6 ]


The  Max Planck Institute for Infection Biology  continues its research into chlamydia infection. [ 7 ] [ 8 ] [ 9 ]  The institute has published over 140 studies related to chlamydia. [ 10 ]


There are research projects in several areas at the  Queensland University of Technology , including development of a human vaccine for chlamydial sexually transmitted disease and understanding basic mechanisms of regulation, including the importance of chlamydial  proteases . Chlamydia infections in wildlife are part of the research into chlamydia, particularly koalas' genomics and gene regulation studies in chlamydia. [ 11 ]


A sample list of primary publications: [ 11 ]


Vaccine development at the  University of Southampton  continues. [ 12 ] [ 13 ]


Vaccine research is ongoing in independent and institutional settings. [ 14 ] [ 15 ]  CTH522 has completed phase 1 trials [ 16 ]


Clinical trials are used by researchers investigating the efficacy of interventions or protocol in the epidemiology, detection, prevention and treatment of chlamydia infections. Interventions are the use of medical products, medication, devices, procedures or changes in the participants' behavior. The effects on the participants are measured and compared to previous trials, placebo or a new medical approach, or to no intervention. [ 17 ]  The National Institutes of Health support ongoing research in the study of chlamydia infection. At least 113 studies have been initiated as of 2015. [ 17 ] [ 18 ]  One example was the clinical trial of eye prophylaxis in newborns in the prevention of neonatal conjunctivitis caused by Chlamydia trachomatis. [ 19 ]


Research related to chlamydia can take the form of an observational study. This type of study assesses outcomes in groups of participants according to a research plan or protocol. The volunteers in the study may receive interventions such as medical products, medications, devices, or procedures as part of their routine medical care. The volunteers in this type of study are not assigned to specific interventions as in a clinical trial. [ 20 ]  An example of an observational study regarding chlamydia infection was "Non-Invasive Sexually Transmitted Disease (STD) Testing in Women Seeking Emergency Contraception or Urine Pregnancy Testing: Meeting the Needs of an At-Risk Population" in 2010. [ 21 ]  Observational studies employ the use of randomised control studies. [ 22 ]


Case studies that research the prevalence and prevention of chlamydia can include personal contact, a detailed history of the participants, extensive physical examinations, and related contextual conditions. Chlamydia case studies also can be produced by following a formal research method. These case studies are likely to appear in formal research venues, such as journals, professional conferences, and administrative science. [ 23 ] [ 24 ]


In doing case study research, the case being studied may be an individual, organization, event, or action, existing in a specific time and place. For instance, clinical science has produced both well-known case studies of individuals and also case studies of clinical practices. [ 25 ] [ 26 ] [ 27 ]


Evidence-based medicine  chlamydia studies optimizes  decision-making  by employing the use of information based upon well-designed  research . This approach to the study of chlamydia requires that only research conducted coming from  meta-analyses ,  systematic reviews , and  randomized controlled trials ) can yield widely applied recommendations. [ 28 ] [ 29 ] [ 30 ]  Some examples of evidence-based research on chlamydia include:


Using Wikipedia for Research


Chlamydia trachomatis  ( / k l ə ˈ m ɪ d i ə   t r ə ˈ k oʊ m ə t ɪ s / ) is a Gram-negative,  anaerobic  bacterium responsible for  chlamydia  and  trachoma .  C. trachomatis  exists in two forms, an extracellular infectious elementary body (EB) and an intracellular non-infectious reticulate body (RB). [ 2 ]  The EB attaches to host cells and enter the cell using  effector proteins , where it transforms into the metabolically active RB. Inside the cell, RBs rapidly replicate before transitioning back to EBs, which are then released to infect new host cells. [ 3 ]


The earliest description of  C. trachomatis  was in 1907 by Stanislaus von Prowazek and Ludwig Halberstädter as a protozoan. [ 4 ]  It was later thought to be a virus due to its small size and inability to grow in laboratories. It was not until 1966 when it was discovered as a bacterium by  electron microscopy  after its internal structures were visually observed.


There are currently 18  serovars  of  C. trachomatis,  each associated with specific diseases affecting mucosal cells in the lungs, genital tracts, and ocular systems. [ 3 ]  Infections are often asymptomatic, but can lead to severe complications such as  pelvic inflammatory disease  in women and  epididymitis  in men. The bacterium also causes  urethritis ,  conjunctivitis , and  lymphogranuloma venereum  in both sexes.  C. trachomatis   genitourinary  infections are diagnosed more frequently in women than in men, with the highest prevalence occurring in females aged 15 to 19 years of age. [ 5 ] [ 6 ] [ 7 ]  Infants born from mothers with active chlamydia infections have a pulmonary infection rate that is less than 10%. [ 8 ]  Globally, approximately 84 million people are affected by  C. trachomatis  eye infections, with 8 million cases resulting in blindness. [ 9 ]   C. trachomatis  is the leading infectious cause of blindness and the most common sexually transmitted bacterium. [ 3 ]


The impact of  C. trachomatis  on human health has been driving vaccine research since its discovery. [ 10 ]  Currently, no vaccines are available, largely due to the complexity of the immunological pathways involved in  C. trachomatis , which remain poorly understood. However,  C. trachomatis  infections may be treated with several antibiotics, with  tetracycline  being the preferred option. [ 11 ] [ 12 ]


Chlamydia trachomatis  is a  gram-negative  bacterium that can replicate exclusively within a host cell, making it an obligate intracellular pathogen. [ 3 ]  Over the course of its life cycle,  C. trachomatis  takes on two distinct forms to facilitate infection and replication. Elementary bodies (EBs) are 200 to 400  nanometers  across and are surrounded by a rigid cell wall that enables them to survive in an extracellular form. [ 3 ] [ 10 ]  When an EB encounters a susceptible host cell, it binds to the cell surface and is internalized. [ 3 ]  The second form, reticulate bodies (RBs) are 600 to 1500 nanometers across, and are found only within host cells. [ 10 ]  RBs have increased metabolic activity and are adapted for replication. Neither form is motile. [ 10 ]


The evolution of  C. trachomatis  includes a reduced genome of approximately 1.04  megabases , encoding approximately 900 genes. [ 3 ]   In addition to the  chromosome  that contains most of the genome, nearly all  C. trachomatis  strains carry a 7.5  kilobase   plasmid  that contains 8 genes. [ 10 ]  The role of this plasmid is unknown, although strains without the plasmid have been isolated, suggesting it is not essential for bacterial survival. [ 10 ]  Several important metabolic functions are not encoded in the  C. trachomatis  genome and are instead scavenged from the host cell. [ 3 ]


C. trachomatis  has a reduced metabolic capacity due to its smaller genome, which lacks genes for many biosynthetic pathways including those required for complete  carbohydrate metabolism . [ 3 ] [ 13 ]  The bacterium is largely dependent on the host cell for metabolic intermediates and energy, particularly in the form of  adenosine triphosphate  (ATP). [ 13 ]   C. trachomatis  lacks several enzymes necessary for independent glucose metabolism, and instead utilizes two ATP/ ADP   translocases  (Npt1 and Npt2) to import ATP from the host cell. [ 14 ]  Other metabolites including amino acids, nucleotides, and lipids are also transported from the host. [ 13 ] [ 15 ]


A critical enzyme involved in  glycolysis ,  hexokinase , is absent in  C. trachomatis,  preventing the production of  glucose-6-phosphate  (G6P). Instead, G6P from the host cell is taken up by the metabolically active reticulate bodies (RBs) through a G6P transporter (UhpC antiporter). [ 15 ] [ 13 ]  Although  C. trachomatis  lacks a complete independent glycolysis pathway, it has genes encoding for all the enzymes required for the  Pentose Phosphate Pathway  (PPP),  gluconeogenesis , and  glycogen  synthesis and degradation. [ 13 ]


A suppressor of glycolysis,  p53 , is expressed less frequently in  c. trachomatis  cells, increasing the rate at which glycolysis occurs, even in the presence of oxygen. [ 13 ]  As a result,  C. trachomatis  infection is associated with increased production of  pyruvate ,  lactate , and  glutamate  by the bacterium due to activity of the  pyruvate dehydrogenase kinase 2 enzyme  limiting conversion of pyruvate to  acetyl-coenzyme A . [ 13 ]  The pyruvate is instead turned into lactate, which allows the cell to grow almost unobstructed by immune response due to the acidic properties of lactate. [ 13 ] [ 16 ]  Excess glycolytic products are, in turn, brought into the PPP to create nucleotides and for biosynthesis. [ 13 ]  This type of growth is very similar to the  Warburg effect  observed in cancer cells. [ 13 ]


Like other  Chlamydia  species,  C. trachomatis  has a life cycle consisting of two morphologically distinct forms. First,  C. trachomatis  attaches to a new host cell as a small spore-like form called the elementary body. [ 17 ]  The elementary body enters the host cell, surrounded by a host  vacuole , called an inclusion. [ 17 ]  Within the inclusion,  C. trachomatis  transforms into a larger, more metabolically active form called the reticulate body. [ 17 ]  The reticulate body substantially modifies the inclusion, making it a more hospitable environment for rapid replication of the bacteria, which occurs over the following 30 to 72 hours. [ 17 ]  The massive number of intracellular bacteria then transition back to resistant elementary bodies before causing the cell to rupture and being released into the environment. [ 17 ]  These new elementary bodies are then shed in the semen or released from epithelial cells of the female genital tract and attach to new host cells. [ 18 ]


C. trachomatis  are bacteria in the genus  Chlamydia , a group of obligate intracellular parasites of  eukaryotic cells . [ 3 ]  Chlamydial cells cannot carry out energy metabolism and they lack biosynthetic pathways. [ 19 ]


C. trachomatis  strains are generally divided into three  biovars  based on the type of disease they cause. These are further subdivided into several  serovars  based on the surface  antigens  recognized by the immune system. [ 3 ]  Serovars A through C cause trachoma, which is the world's leading cause of preventable infectious blindness. [ 20 ]  Serovars D through K infect the genital tract, causing pelvic inflammatory disease,  ectopic pregnancies , and infertility. Serovars L1 through L3 cause an invasive infection of the lymph nodes near the genitals, called  lymphogranuloma venereum . [ 3 ]


C. trachomatis  is thought to have diverged from other  Chlamydia  species around 6 million years ago. This genus contains a total of nine species:  C. trachomatis ,  C. muridarum ,  C. pneumoniae ,  C. pecorum ,  C. suis ,  C. abortus ,  C. felis ,  C. caviae , and  C. psittaci . The closest relative to  C. trachomatis  is  C. muridarum , which infects mice. [ 17 ]   C. trachomatis  along with  C. pneumoniae  have been found to infect humans to a greater extent.  C. trachomatis  exclusively infects humans.  C. pneumoniae  is found to also infect horses, marsupials, and frogs. Some of the other species can have a considerable impact on human health due to their known zoonotic transmission. [ 3 ]


Strains that cause  lymphogranuloma venereum  (Serovars L1 to L3)


Most prevalent genital strains (Serovars D-F)


Less prevalent genital strains (Serovars G-K, and some strains of Serovar D)


Ocular strains (Serovars A-C)


Clinical signs and symptoms of  C. trachomatis  infection in the genitalia present as the chlamydia infection, which may be asymptomatic or may resemble a  gonorrhea  infection. [ 11 ]
Both are common causes of multiple other conditions including pelvic inflammatory disease and  urethritis . [ 5 ]


C. trachomatis  is the single most important infectious agent associated with blindness (trachoma), and it also affects the eyes in the form of inclusion conjunctivitis and is responsible for about 19% of adult cases of conjunctivitis. [ 6 ]


C. trachomatis  in the lungs presents as the chlamydia pneumoniae respiratory infection and can affect all ages. [ 21 ]


Elementary bodies are generally present in the semen of infected men and vaginal secretions of infected women. [ 18 ]  When they come into contact with a new host cell, the elementary bodies bind to the cell via interaction between  adhesins  on their surface and several host receptor proteins and  heparan sulfate proteoglycans . [ 3 ]  Once attached, the bacteria inject various effector proteins into the host cell using a  type three secretion system . [ 3 ]  These effectors trigger the host cell to take up the elementary bodies and prevent the cell from triggering  apoptosis . [ 3 ]  Within 6 to 8 hours after infection, the elementary bodies transition to reticulate bodies and a number of new effectors are synthesized. [ 3 ]  These effectors include a number of proteins that modify the inclusion membrane (Inc proteins), as well as proteins that redirect host vesicles to the inclusion. [ 3 ]  8 to 16 hours after infection, another set of effectors are synthesized, driving acquisition of nutrients from the host cell. [ 3 ]  At this stage, the reticulate bodies begin to divide, coinciding with the expansion of the inclusion. [ 3 ]  If several elementary bodies have infected a single cell, their inclusions will fuse at this point to create a single large inclusion in the host cell. [ 3 ]  From 24 to 72 hours after infection, reticulate bodies transition to elementary bodies which are released either by lysis of the host cell or extrusion of the entire inclusion into the host genital tract. [ 3 ]


The chlamydial plasmid, a DNA molecule existing separately from the genome of  C. trachomatis , functions to enhance genetic diversity via the genes encoded. [ 22 ]  The plasmid gene protein 3 ( pgp3 ) has been linked to the establishment of persistent infection within the genital tract by suppressing the host immune response. [ 23 ]


Polymorphic outer membrane proteins (Pmp proteins) on the surface of  C. trachomatis  use tropism to bind specific host cell receptors, which in turn initiates infection. [ 24 ]  Pmp proteins B, D, and H have been most associated with eliciting a pro-inflammatory response through the release of cytokines. [ 25 ]


CPAF (Chlamydia Protease-like Activity Factor) functions by preventing the host from triggering the proper immune response.  C. trachomatis  use of CPAF targets and cleaves proteins that restructure the Golgi apparatus and activate DNA repair so that  C. trachomatis  is able to use the host cell machinery and proteins to its advantage. [ 26 ]


Most people infected with  C. trachomatis  are asymptomatic. However, the bacteria can present in one of three ways: genitourinary (genitals), pulmonary (lungs), and ocular (eyes). [ 7 ]


Genitourinary cases can include genital discharge, vaginal bleeding, itchiness (pruritus), painful urination (dysuria), among other symptoms. [ 8 ]  Often, symptoms are similar to those of a  urinary tract infection . [ citation needed ]


When  C. trachomatis  presents in the eye in the form of trachoma, it begins by gradually thickening the eyelids and eventually begins to pull the eyelashes into the eyelid. [ 27 ]  In the form of inclusion conjunctivitis, the infection presents with redness, swelling, mucopurulent discharge from the eye, and most other symptoms associated with adult conjunctivitis. [ 6 ]


C. trachomatis  may latently infect the  chorionic villi  tissues of pregnant women, thereby impacting pregnancy outcome. [ 28 ]


Three times as many women are diagnosed with genitourinary  C. trachomatis  infections as men. Women aged 15–19 have the highest prevalence, followed by women aged 20–24, although the rate of increase of diagnosis is greater for men than for women. Risk factors for genitourinary infections include unprotected sex with multiple partners, lack of condom use, and low socioeconomic status living in urban areas. [ 7 ]


Pulmonary infections can occur in infants born to women with active chlamydia infections, although the rate of infection is less than 10%. [ 8 ]


Ocular infections take the form of inclusion conjunctivitis or trachoma, both in adults and children. About 84 million worldwide develop  C. trachomatis  eye infections and 8 million are blinded as a result of the infection. [ 9 ]  Trachoma is the primary source of infectious blindness in some parts of rural Africa and Asia and is a  neglected tropical disease  that has been targeted by the World Health Organization for elimination by 2020. [ 29 ]  Inclusion conjunctivitis from  C. trachomatis  is responsible for about 19% of adult cases of conjunctivitis. [ 6 ]


Treatment depends on the infection site, age of the patient, and whether another infection is present. Having a  C. trachomatis  and one or more other  sexually transmitted infections  at the same time is possible. Treatment is often done with both partners simultaneously to prevent reinfection.  C. trachomatis  may be treated with several antibiotic medications, including  azithromycin ,  erythromycin ,  ofloxacin , [ 11 ]  and  tetracycline .


Tetracycline is the most preferred antibiotic to treat  C.trachomatis  and has the highest success rate .   Azithromycin  and  doxycycline  have equal efficacy to treat  C. trachomatis  with 97 and 98 percent success, respectively. Azithromycin is dosed as a 1 gram tablet that is taken by mouth as a single dose, primarily to help with concerns of non-adherence. [ 12 ]  Treatment with generic doxycycline 100  mg twice a day for 7 days has equal success with expensive delayed-release doxycycline 200 mg once a day for 7 days. [ 12 ]  Erythromycin is less preferred as it may cause gastrointestinal side effects, which can lead to non-adherence. Levofloxacin and ofloxacin are generally no better than azithromycin or doxycycline and are more expensive. [ 12 ]


If treatment is necessary during pregnancy,  levofloxacin , ofloxacin, tetracycline, and  doxycycline  are not prescribed. In the case of a patient who is pregnant, the medications typically prescribed are azithromycin,  amoxicillin , and erythromycin. Azithromycin is the recommended medication and is taken as a 1 gram tablet taken by mouth as a single dose. [ 12 ]  Despite amoxicillin having fewer side effects than the other medications for treating antenatal  C. trachomatis  infection, there have been concerns that pregnant women who take penicillin-class antibiotics can develop a chronic persistent chlamydia infection. [ 30 ]  Tetracycline is not used because some children and even adults can not withstand the drug, causing harm to the mother and fetus. [ 12 ]  Retesting during pregnancy can be performed three weeks after treatment. If the risk of reinfection is high, screening can be repeated throughout pregnancy. [ 11 ]


If the infection has progressed, ascending the reproductive tract and pelvic inflammatory disease develops, damage to the fallopian tubes may have already occurred. In most cases, the  C. trachomatis  infection is then treated on an outpatient basis with azithromycin or doxycycline. Treating the mother of an infant with  C. trachomatis  of the eye, which can evolve into pneumonia, is recommended. [ 11 ]  The recommended treatment consists of oral erythromycin base or ethylsuccinate 50 mg/kg/day divided into four doses daily for two weeks while monitoring for symptoms of  infantile hypertrophic pyloric stenosis  (IHPS) in infants less than 6 weeks old. [ 12 ]


There have been a few reported cases of  C.trachomatis  strains that were resistant to multiple antibiotic treatments. However, as of 2018, this is not a major cause of concern as antibiotic resistance is rare in  C.trachomatis  compared to other infectious bacteria. [ 31 ]


Chlamydia  species are readily identified and distinguished from other  Chlamydia  species using DNA-based tests. Tests for Chlamydia can be ordered from a doctor, a lab or online. [ 32 ]


Most strains of  C. trachomatis  are recognized by  monoclonal antibodies  (mAbs) to epitopes in the VS4 region of MOMP. [ 33 ]  However, these mAbs may also cross-react with two other  Chlamydia  species,  C. suis  and  C. muridarum . [ citation needed ]


Studies have revealed antibiotic resistance in  Chlamydia trachomatis . Mutations in the 23S rRNA gene, including A2057G and A2059G, have been identified as significant contributors to resistance against azithromycin, a commonly used treatment. This resistance is linked to treatment failures and persistent infections, necessitating ongoing research into alternative antibiotics, such as  moxifloxacin , as well as non-antibiotic approaches like  bacteriophage therapy . These innovations aim to combat resistance while reducing the overall burden of antibiotic misuse, which has been closely associated with the rise of resistant strains in  C. trachomatis  populations. [ 37 ]


Additionally, diagnostic improvements have played a vital role in identifying  C. trachomatis  infections more efficiently.  Nucleic acid amplification tests  (NAATs), such as DNA- and RNA-based tests, have shown high sensitivity and specificity, making them the gold standard for detecting asymptomatic infections. NAATs have facilitated broader screening programs, particularly in high-risk populations, and are integral to public health initiatives aimed at controlling the spread of  C. trachomatis . Research continues into point-of-care diagnostic tools, which promise faster results and greater accessibility, especially in low-resource settings. [ 38 ]


In the area of vaccine development, creating an effective vaccine for  C. trachomatis  has proven challenging due to the complex immune responses the bacterium elicits. Subunit vaccines, which target outer membrane proteins like MOMP (Major Outer Membrane Protein) and polymorphic membrane proteins (Pmp), are being explored in both animal models and early human trials. While these vaccines show promise in inducing partial immunity in murine models, further research is needed to evaluate their efficacy in humans. The goal is to develop a vaccine that can prevent reinfection without causing harmful inflammatory responses. [ 39 ]


C. trachomatis  was first described in 1907 by Stanislaus von Prowazek and Ludwig Halberstädter in scrapings from trachoma cases. [ 40 ] [ 17 ]  Thinking they had discovered a "mantled protozoan", they named the organism "Chlamydozoa" from the Greek "Chlamys" meaning mantle. [ 17 ]  Over the next several decades, "Chlamydozoa" was thought to be a virus as it was small enough to pass through bacterial filters and unable to grow on known laboratory media. [ 17 ]  However, in 1966,  electron microscopy  studies showed  C. trachomatis  to be a bacterium. [ 17 ]  This is essentially due to the fact that they were found to possess DNA, RNA, and  ribosomes  like other bacteria. It was originally believed that Chlamydia lacked  peptidoglycan  because researchers were unable to detect  muramic acid  in cell extracts. [ 41 ]  Subsequent studies determined that  C. trachomatis  synthesizes both  muramic acid  and  peptidoglycan , but relegates it to the microbe's division septum and does not utilize it for construction of a cell wall. [ 42 ] [ 43 ]  The bacterium is still classified as gram-negative. [ 44 ]


C. trachomatis  agent was first cultured and isolated in the yolk sacs of eggs by  Tang Fei-fan   et al.  in 1957. [ 45 ]  This was a significant milestone because it became possible to preserve these agents, which could then be used for future genomic and phylogenetic studies. The isolation of  C. trachomatis  coined the term isolate to describe how  C. trachomatis  has been isolated from an  in vivo  setting into a "strain" in cell culture. [ 46 ]  Only a few "isolates" have been studied in detail, limiting the information that can be found on the evolutionary history of  C. trachomatis . [ 45 ] [ 47 ]


In the 1990s it was shown that there are several species of  Chlamydia .  Chlamydia trachomatis  was first described in historical records in Ebers papyrus written between 1553 and 1550 BC. [ 48 ]  In the ancient world, it was known as the blinding disease trachoma. The disease may have been closely linked with humans and likely predated civilization. [ 49 ]  It is now known that  C. trachomatis  comprises 19  serovars  which are identified by monoclonal antibodies that react to  epitopes  on the major outer-membrane protein (MOMP). [ 50 ]  Comparison of amino acid sequences reveals that MOMP contains four variable segments: S1,2 ,3 and 4. Different variants of the gene that encodes for MOMP, differentiate the genotypes of the different serovars. The antigenic relatedness of the serovars reflects the homology levels of DNA between MOMP genes, especially within these segments. [ 51 ]


Furthermore, there have been over 220  Chlamydia  vaccine trials done on mice and other non-human host species to target  C. muridarum  and  C. trachomatis  strains. However, it has been difficult to translate these results to the human species due to physiological and anatomical differences. Future trials are working with closely related species to humans. [ 52 ]


Chronic bacterial prostatitis  ( CBP ) is a  bacterial   infection  of the  prostate gland  and a form of  prostatitis  (prostate inflammation). It should be distinguished from other forms of prostatitis such as  acute bacterial prostatitis  (ABP) and  chronic pelvic pain syndrome  (CPPS). [ 1 ]


Chronic bacterial prostatitis is a relatively rare condition that usually presents with an intermittent  UTI -type picture. It is defined as recurrent urinary tract infections in men originating from a chronic infection in the prostate. Symptoms may be completely absent until there is also bladder infection, and the most troublesome problem is usually recurrent  cystitis . [ 2 ]  It has been said that recurrent and relapsing UTIs (i.e., UTIs due to the same pathogen) are a hallmark of chronic bacterial prostatitis. [ 3 ] [ 4 ] [ 5 ]


Chronic bacterial prostatitis occurs in less than 5% of patients with prostate-related non- BPH  lower urinary tract symptoms (LUTS). [ citation needed ]


Dr. Weidner, Professor of Medicine, Department of Urology, University of Gießen, has stated: "In studies of 656 men, we seldom found chronic bacterial prostatitis. It is truly a rare disease. Most of those were E-coli." [ 6 ]


Chronic bacterial prostatitis is thought to be caused by ascending  urethral infection  and by reflux into the  ejaculatory duct  or  prostatic ducts . [ 7 ]   Risk factors  for chronic bacterial prostatitis include functional or anatomic abnormalities,  catheterization , prostate  biopsy  or  urethritis  (due to  sexually transmitted infections ), and unprotected penetrative  anal sex . [ 7 ]  In theory, the ability of some strains of bacteria to form  biofilms  might be one of the factors that facilitate the development of chronic bacterial prostatitis. [ 8 ]  Recurrent infections may be caused by inefficient urination ( benign prostatic hyperplasia ,  neurogenic bladder ), prostatic stones, or a structural abnormality that acts as a reservoir for infection. [ citation needed ]


In chronic bacterial prostatitis, there are bacteria in the prostate, but there may be no symptoms or milder symptoms than occur with  acute prostatitis . [ 9 ]  The prostate infection is diagnosed by culturing urine as well as prostate fluid (expressed prostatic secretions or EPS) which are obtained by the doctor performing a rectal exam and putting pressure on the prostate. If no fluid is recovered after this prostatic massage, a post massage urine should also contain any prostatic bacteria. [ citation needed ]


Prostate specific antigen  levels may be elevated, although there is no malignancy.  Semen analysis  is a useful diagnostic tool. [ 10 ]  Semen cultures are also performed. Antibiotic sensitivity testing is also done to select the appropriate antibiotic. Other useful markers of infection are seminal elastase and seminal cytokines. [ citation needed ]


Antibiotics  are effective in the treatment of chronic bacterial prostatitis and are a  first-line therapy  for the condition. [ 11 ]  A blood–prostate barrier exists that prevents many antibiotics from penetrating the prostate and achieving adequate antibacterial concentrations. [ 12 ] [ 13 ] [ 14 ]  As such, only certain classes of antibiotics are effective and recommended for treatment of chronic bacterial prostatitis. [ 11 ] [ 15 ]  These include  fluoroquinolones  like  ciprofloxacin  and  levofloxacin ;  trimethoprim ;  tetracyclines  like  doxycycline ; and  macrolides  like  azithromycin  and  clarithromycin . [ 11 ] [ 15 ] [ 16 ]  Fluoroquinolones are the first-line antibiotics for chronic bacterial prostatitis, whereas trimethoprim and tetracyclines are second-line antibiotics and azithromycin is reserved for special situations. [ 11 ] [ 15 ]   Fosfomycin  has also been repurposed for chronic bacterial prostatitis and is increasingly being employed in its treatment. [ 15 ] [ 17 ] [ 16 ]  Antibiotic therapy of chronic bacterial prostatitis requires prolonged antibiotic courses of generally 4 to 6   weeks of treatment, but up to 12   weeks of treatment. [ 11 ] [ 15 ] [ 7 ]  Microbiological eradication rates have ranged from 40 to 77% for ciprofloxacin, 75 to 86% for levofloxacin, 77% for doxycycline, 80% for azithromycin, 80% for clarithromycin, and 62 to 77% for a combination of ciprofloxacin and azithromycin. [ 11 ] [ 18 ]  Although antibiotics are effective in the curative treatment of chronic bacterial prostatitis, recurrence rates are high and range from 25 to 50%. [ 19 ]


Levofloxacin (the  levorotatory   enantiomer  of  ofloxacin ) has been found to reach prostatic fluid concentrations that are 5.5   times higher than those of the same dose of ciprofloxacin. [ 20 ] [ 21 ] [ 22 ]  These findings indicate that levofloxacin has a greater ability to penetrate the prostate than ciprofloxacin and suggest that it might be comparatively more effective in the treatment of chronic bacterial prostatitis. [ 20 ] [ 21 ] [ 22 ]  However, clinical findings have been mixed, with one large  clinical trial  finding that levofloxacin was more effective than ciprofloxacin (bacterial eradication rate = 86% vs. 60%; clinical cure/improvement = 93% vs. 72%; bacterial recurrence rate = 4% vs. 19%) and another similarly large trial finding that they were equivalent (bacterial eradication rate = 75% vs. 77%; clinical cure/improvement = 75% vs. 73%). [ 11 ] [ 20 ] [ 18 ] [ 23 ]  Moxifloxacin shows even greater prostatic penetration than levofloxacin as well as a broader spectrum of antibacterial activity, with improved activity against  Gram-positive bacteria  and  anaerobic pathogens . [ 16 ] [ 19 ]  It may be the only fluoroquinolone able to obtain prostatic concentrations that are 10-fold above the  minimum inhibitory concentration  (MIC) against  Enterococcus faecalis . [ 19 ]  However, limited experience with and data on moxifloxacin for chronic bacterial prostatitis are available as of 2022. [ 19 ] [ 16 ]  Another limitation of moxifloxacin for such purposes is that it may have greater  safety  concerns than other fluoroquinolones, for instance higher  cardiovascular risks . [ 16 ]  Other fluoroquinolones that have also been used and found effective in the treatment of chronic bacterial prostatitis include  norfloxacin ,  lomefloxacin ,  ofloxacin , and  prulifloxacin . [ 24 ] [ 16 ]


Aside from fluoroquinolones, certain other antibiotics with the potential for improved activity, including  minocycline ,  tigecycline ,  linezolid ,  daptomycin ,  clindamycin , and  vancomycin , have also been used limitedly  off-label  in the treatment of chronic bacterial prostatitis with reported success. [ 16 ] [ 15 ] [ 24 ]  However, the  safety  of novel antibiotics for treatment of chronic bacterial prostatitis is understudied and significant  toxicities  are known for many of them, which is especially of concern due to the long treatment courses required. [ 16 ]  Antibiotics with poor prostatic penetration that may not be suitable for curative treatment of chronic bacterial prostatitis include  nitrofurantoin , [ 25 ] [ 26 ] [ 17 ] [ 12 ] [ 27 ]   sulfamethoxazole , most  penicillins  (e.g.,  ampicillin ,  penicillin G ),  aminoglycosides , most  cephalosporins , other  β-lactams , and the tetracycline  oxytetracycline , among others. [ 7 ] [ 12 ] [ 16 ] [ 27 ]  Findings on the penetration of  amoxicillin  into the prostate are inconsistent, with prostate tissue levels of 0.77 and 26.4   μg/mL reported in two different studies. [ 12 ] [ 28 ]  Clinical findings of  amoxicillin/clavulanic acid  for treatment of chronic bacterial prostatitis are also mixed, with reports of high rates of both success [ 26 ] [ 29 ] [ 30 ]  and failure. [ 31 ] [ 32 ]  The more lipophilic tetracyclines minocycline and doxycycline show good or excellent prostate penetration like ciprofloxacin. [ 27 ] [ 12 ] [ 33 ]


In some men, chronic bacterial prostatitis can be severe and highly refractory to treatment or relapsing. [ 34 ] [ 35 ]  In addition, it can be life-threatening due to  urinary tract infections  (UTIs). [ 35 ]   Prostatectomy , or prostate removal surgery, has been used rarely and in well-selected patients to treat these kinds of cases. [ 34 ] [ 35 ]  A 2017  systematic review  evaluated prostatectomy for chronic prostatitis. [ 34 ]   Transurethral resection of the prostate  (TURP) by  electrocautery  was done in 110   patients, and in these individuals, symptoms were cured in 70%, improved in 15%, and unchanged in 15%. [ 34 ]   Radical prostatectomy  was done in 21   patients and resulted in symptoms being cured in 95%. [ 34 ]  There are significant rates of  erectile dysfunction  and  urinary incontinence  with prostatectomy. [ 34 ] [ 35 ]  These complications can be reduced with  minimally invasive  and  nerve-sparing  surgical techniques, such as  robotically assisted  radical prostatectomy or  laparoscopic prostatectomy . [ 34 ] [ 35 ]  However, significant rates of complications still occur even with minimally invasive forms of prostatectomy. [ 34 ] [ 35 ]  All of the studies in the 2017 systematic review were  prospective  or  retrospective   case series  and there were no  randomized controlled trials . [ 34 ]  As such, little evidence is available to inform clinical decision-making in terms of prostatectomy for chronic prostatitis. [ 34 ]


The addition of  prostate massage  to courses of antibiotics was previously proposed as being beneficial and prostate massage may mechanically break up the biofilm and enhance the drainage of the prostate gland. [ 36 ] [ 37 ]  However, in more recent trials, this was not shown to improve outcome compared to antibiotics alone. [ 38 ]


Bacteriophages  hold promise as another potential treatment for chronic bacterial prostatitis. [ 7 ] [ 39 ]


Persistent infections may be helped in 80% of patients by the use of  alpha blockers  ( α 1 -adrenergic receptor   antagonists ) or by long-term low-dose antibiotic therapy. [ 11 ] [ 25 ] [ 40 ]  Alpha blockers, including  tamsulosin ,  alfuzosin , and  doxazosin  among others, are used specifically in the management of voiding  lower urinary tract symptoms  (LUTS) like slow urinary flow or urinary hesitancy, although they might also help with pain and other symptoms. [ 11 ]  However, their effectiveness is modest and the clinical significance has been questioned. [ 11 ]  Possibilities for low-dose suppressive antibiotic therapy include  nitrofurantoin ,  trimethoprim/sulfamethoxazole ,  fluoroquinolones ,  cephalosporins , and  tetracyclines . [ 25 ] [ 40 ]  Prostate-penetrant  nonsteroidal anti-inflammatory drugs  (NSAIDs), like  celecoxib  and  rofecoxib , as well as possibly  ibuprofen ,  naproxen , and  diclofenac , can also be used as  analgesics  to treat pain and  inflammation  in chronic bacterial prostatitis. [ 7 ] [ 41 ]


Methenamine  is a  urinary   antiseptic  and  antibacterial agent  which is used in the prevention of recurrent  urinary tract infections  (UTIs). [ 42 ]  It is non-inferior to low-dose  prophylactic  antibiotics for this purpose. [ 43 ] [ 44 ] [ 45 ]  In contrast however, methenamine itself is not an antibiotic and does not promote  antibiotic resistance . [ 42 ] [ 43 ]  The drug works by being  selectively  and  pH -dependently  decomposed  in  acidic  environments like the  bladder  into the active form  formaldehyde , which is  potently   bactericidal . [ 42 ]  Since formaldehyde is only formed from methenamine in acidic environments, it is not expected to be effective in the curative treatment of chronic bacterial prostatitis, and hence is not recommended for such purposes. [ 42 ]  Methenamine decomposes into formaldehyde at a pH of below 6, [ 42 ]  whereas the normal pH of prostatic fluid is 6.5 to 6.7 and in chronic prostatitis the pH is 7.0 to 8.3. [ 12 ]  However, in persistent chronic bacterial prostatitis, prophylactic methenamine may be useful as an alternative to low-dose prophylactic antibiotics in preventing prostatitis-derived UTIs and managing associated symptoms. [ 25 ]  Prophylactic low-dose methenamine combined with an  ascorbic acid  (vitamin C)  supplement , which is theorized to enhance its activity by making the urine more acidic, has been reported to be effective for this purpose based on  clinical experience . [ 25 ]  In any case, supporting clinical data for this use are lacking as of 2020. [ 25 ]


Androgen deprivation therapy  with  surgical castration ,  estrogens , and the  5α-reductase inhibitor   finasteride  have shown beneficial effects on chronic bacterial prostatitis in terms of bacterial growth and inflammation in  animal models , but clinical studies in humans have not been performed. [ 19 ] [ 46 ] [ 47 ]


Over time, the relapse rate is high, exceeding 50%. However, recent research indicates that combination therapies offer a better prognosis than antibiotics alone.


A 2007 study showed that repeated combination  pharmacological therapy  with antibacterial agents (ciprofloxacin/azithromycin), alpha-blockers (alfuzosin) and Serenoa repens extracts may eradicate infection in 83.9% of patients with clinical remission extending throughout a follow-up period of 30 months for 94% of these patients. [ 48 ]


A 2014 study of 210 patients randomized into two treatment groups found that recurrence occurred within 2   months in 27.6% of the group using antibiotics alone (prulifloxacin 600   mg), but in only 7.8% of the group taking prulifloxacin in combination with  Serenoa repens  extract,  Lactobacillus sporogens  (now  Heyndrickxia coagulans ), and  arbutin  (a combination referred to by the name "Lactorepens"). [ 49 ]


Large prostatic stones was shown to be related with the presence of bacteria, [ 50 ]  a higher urinary symptoms and pain score, a higher  IL-1β  and  IL-8  concentration in seminal plasma, a greater prostatic inflammation and a lower response to antibiotic treatment. [ 51 ]


In a 2008  systematic review  of 10,617   men, 8.2% had experienced prostatitis symptoms. [ 11 ] [ 52 ]  It has been estimated that 35 to 50% of men may be affected by prostatitis symptoms during their lifetime. [ 11 ]


Clutton's joints  is a term describing the finding of symmetrical joint swelling seen in  congenital syphilis . It most commonly affects the  knees , presenting with  synovitis  and joint effusions (collections of fluid within the  joint capsules ) lasting up to a year. It has also been reported affecting the ankles, elbows, wrists and fingers. It is usually painless, although pain in the absence of trauma can occur in a few cases. There is usually no disability associated with the joint swelling, and recovery is usually complete. It occurs between 5 and 20 years of age in both sexes. [ citation needed ] The condition was described in 1886 by  Henry Hugh Clutton  in  The Lancet . [ 1 ]


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Cor bovinum   or  cor bovis  refers to a massive  hypertrophy  of the  left ventricle  of the  heart  due to volume overload, usually in earlier times in the context of tertiary  syphilis  but currently more often due to chronic  aortic regurgitation ,  hypertensive  and  ischaemic heart disease .


Due to  syphilitic aortitis  (a complication of tertiary  syphilis ) the aortic valve ring becomes dilated. The free margins of valve cusps no longer approximate leading to aortic valve insufficiency.  As blood regurgitates into the  left ventricle  between each  systole ,  volume overload  ensues and the ventricular wall hypertrophies in an attempt to maintain cardiac output and blood pressure.  The massive ventricle can lead to a heart weighing over 1000 grams (the weight of a normal heart is about 350 grams), referred to as  cor bovinum  (Latin for cow's heart). [ 1 ]


Fluri and Gebbers [ 2 ]  define  cor bovinum  as a heart exceeding 500 g in weight. Looking through autopsies on Internal Medicine patients at the Kantonsspital Luzern, they found 415 cases out of 1181 autopsies in the two periods 1978-81 and 1997–2000.  Cor bovinum  was found in 25.3% of cases in the earlier period, with mean age at death 67.7 years, and in the later period 20.6% with mean age 74.3 years. The male female ratio was 4:1. "In 93% of all patients with CB, we found coronary atherosclerosis as a sign of high blood pressure and in 79% a COPD."


In 84% of cases the cause of death was directly related to the  cor bovinum , but in 37% the cause of death was still unclear. They concluded that  cor bovinum  was a decreasing but still frequent autopsy finding. High blood pressure, COPD and male sex were the main risk factors. The decreasing incidence was ascribed to improved medical management: they mention treatments for high blood pressure and coronary artery disease, which suggests that "COPD" in their abstract refers to the latter. [ citation needed ]


A Medline search in January 2008 of articles published since 1950 revealed seven articles on "cor bovinum" (in the earlier part of this period only the titles could be searched), of which only one was in English. A search for dictionary-reported synonyms revealed no mention of "bucardia," and all 101 articles mentioning "ox heart" related to oxen. [ citation needed ]


The  crab louse  or  pubic louse  ( Pthirus pubis ) is an  insect  that is an  obligate   ectoparasite  of  humans , feeding exclusively on  blood . [ 2 ]  The crab louse usually is found in the person's  pubic hair . Although the louse cannot jump, it can also live in other areas of the body that are covered with coarse hair, such as the  perianal area , the entire body (in men), and the  eyelashes  (in children). [ 3 ] [ 4 ]


Humans are the only known hosts of the crab louse, although a closely related species,  Pthirus gorillae , infects  gorillas . The human parasite is thought to have diverged from  Pthirus gorillae  approximately 3.3 million years ago. [ 5 ]  It is more distantly related to the genus  Pediculus , which contains the human  head  and  body lice  and lice that affect  chimpanzees  and  bonobos .


An adult crab louse is about 1.3–2 mm long (slightly smaller than the  body louse  and  head louse ), and can be distinguished from those other species by its almost round body. Another distinguishing feature is that the second and third pairs of legs of a crab louse are much thicker than the front legs and have large claws. [ 6 ]


The eggs of the crab louse are laid usually on the coarse hairs of the  genital  and  perianal  regions of the human body. The female lays about three eggs a day. The eggs take 6–8 days to hatch, and there are three  nymphal  stages which together take 10–17 days before the adult develops, making a total life cycle from egg to adult of 16–25 days. Adults live for up to 30 days. [ 6 ]  Crab lice feed exclusively on blood, and take a blood meal 4–5 times daily. Outside the host they can survive for 24–48 hours. Crab lice are transmitted from person to person most commonly via sexual contact, although  fomites  (bedding, clothing) may play a minor role in their transmission. [ 7 ]


Infestation of the eyelashes is referred to as pediculosis ciliaris or phthiriasis palpebrarum. [ 8 ]


The main symptom of infestation with crab lice is  itching , usually in the pubic-hair area, resulting from  hypersensitivity  to louse saliva, which can become stronger over two or more weeks following initial infestation. In some infestations, a characteristic grey-blue or slate coloration appears ( maculae caeruleae ) at the feeding site, which may last for several days. [ citation needed ]


The prevalence varies between 0.3% to 4.6% with an estimated average of 2% with an increase during war, disasters and in overcrowding. [ 9 ]  Crab louse infestations are not considered a reportable condition by many health authorities, and many cases are self-treated or treated discreetly by physicians. [ 10 ]


It has been suggested that an increasing percentage of humans  removing  their  pubic hair , especially in women, has led to reduced crab louse populations in some parts of the world. [ 11 ] [ 12 ]


While crab lice are not known to transmit disease, the possibility has been raised they may be a vector for  Bartonella spp . and  Acinetobacter spp  which might require further study. [ 13 ]  In infested individuals an average of a dozen lice can be found. Although they are typically found attached to hair in the pubic area, sometimes they are also found on coarse hair elsewhere on the body (for example,  eyebrows ,  eyelashes ,  beard ,  moustache ,  chest ,  armpits , etc.). They do not generally occur on the finer hair of the scalp. [ 6 ] [ 14 ]  Crab lice attach to pubic hair that is thicker than other body hair because their claws are adapted to the specific diameter of pubic hair and other thick hairs of the body. [ 15 ]  Crab louse infestations ( pthiriasis ) are usually spread through  sexual contact  and are most common in adults. [ 15 ] [ 3 ] [ 4 ]  The crab louse can travel up to 25 cm (10 in) on the body. Crab louse infestation is found worldwide and occurs in all races and ethnic groups and in all  socio-economic levels . Occasionally they may be also transmitted by close personal contact or contact with articles such as clothing, bed linen, and towels that have been used by an infested person. [ 7 ] [ 16 ]


Crab lice found on the head or eyelashes of children may be an indication of sexual exposure or abuse. [ 17 ]  Symptoms of crab louse infestation in the pubic area include itching, redness and inflammation. Crab lice are not known to transmit disease; [ citation needed ]  however, secondary  bacterial infection  can occur from scratching of the skin.


Crab louse infestation can be diagnosed by identifying the presence of active stages of the louse, as well as of eggs (nits) on the pubic hair and other hairs of the body. When infestation is diagnosed, other family members and contact persons should also be examined. A magnifying glass or  dermoscope  could be used for better identification. [ 15 ]


Credé prophylaxis  is the practice of washing a newborn's eyes with a 2%  silver nitrate  solution to protect against  neonatal conjunctivitis  caused by  Neisseria gonorrhoeae , thereby preventing blindness. [ 1 ]


The Credé procedure was developed by the German physician  Carl Siegmund Franz Credé  who implemented it in his hospital in  Leipzig  in 1880. [ 1 ]  Between 1881 and 1883, Credé published three papers in  Archiv für Gynäkologie , each titled "Die  Verhütung  der  Augenentzündung  der  Neugeborenen" (Prevention of inflammatory eye disease in the newborn), describing his method and its results. [ 1 ] [ note 1 ]  The original procedure called for a 2% silver nitrate solution administered immediately after birth, as Credé erroneously believed that a 1% solution was ineffective due to a previous study by Hecker; however, this was eventually corrected and reduced back down to a 1% solution to reduce chemical irritation to the newborn's eyes. [ 2 ]


In the 1980s, silver nitrate was replaced by  erythromycin  and  tetracycline  treatments, which are better tolerated by the eye and more effective against  Chlamydia trachomatis  in addition to  N. gonorrhea . [ 3 ]


The works "Archiv für Gynäkologie" are freely available in the public domain.


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Cyrtosomum penneri  are roundworms of the family  Atractidae  that are found in the intestines or lungs of various vertebrate animals. They do not produce eggs; instead the adults produce larvae that are ready to infect as soon as they leave their mother's womb. [ 2 ]   C. penneri  is found only in  Mexico .


Unlike most nematodes, which infect their host by being accidentally swallowed,  C. penneri  is acquired through sexual transmission. In lizards, it is passed through the  cloaca  of the infected lizard to the cloaca of the other during mating, and it has been found, through experiments, that female contraction is 100% percent, while male contraction is about 70%.
In an experiment by the Department of Biology at  Florida Southern College , the researchers found that land snails and crickets do not serve as transport or  intermediate hosts , which supports the idea that  C. penneri  is transferred only during sexual intercourse of the definitive host. [ 3 ]


This  Rhabditida  roundworm-related article is a  stub . You can help Wikipedia by  expanding it .


This  parasitic   animal -related article is a  stub . You can help Wikipedia by  expanding it .


Futsukaichi Rest Home  ( 二日市保養所 ,  Futsukaichi Hoyōjo )  was a specialized medical facility located in the town of Futsukaichi (present day- Chikushino, Fukuoka ), Japan, set up in 1946 by the  Ministry of Welfare  after  World War II . It operated for 1.5 years and performed  abortions  before they were legalized in 1947, and treated  sexually transmitted diseases  (STDs, such as  syphilis  or  gonorrhea ) in rape survivors who were repatriated from China or Korea.


Futsukaichi clinic , or  Futsuka’ichi Sanatorium  are some of its other designations in English.


After the end of World War II, Japanese citizens who had migrated to occupied areas had to return to mainland Japan. During the  repatriation from China  or Korea, they were vulnerable to violence, exposure, and malnutrition.


One of the pioneers at organizing medical help for these refugees was anthropologist  Seiichi Izumi  [ ja ] , who is sometimes credited with being the actual figure who later created the Repatriate Aid Society's "medical corp"  ( 救療部 ,  kyūryō bu ) , the people who operated the Futsukaichi clinic. [ 1 ]


In the immediate postwar Korea, he organized a network of mobile medical teams to help Japanese refugee in transit from Seoul to  Busan . The teams were also posted at major entry ports for repatriates in Japan. Izumi called this network the "mobile medical bureau"  ( 移動医療局 ,  Idō Iryōkyoku ) , although it carried the English name of MRU (Medical Relief Union). It was sanctioned by the  Allied troops . [ 2 ] [ 3 ]  This MRU is considered the precursor to the  kyūryō bu  medical corp that later staffed the Futsukaichi clinic. [ 2 ] [ 3 ]


The  Pusan Nihonjin sewakai  [ ja ]  ("Busan Relief Society", "Busan Homeland Japanese Support Organization", etc.,) and the MRU have been conducting surveys on the medically examined women refugees since December 1945. The figures for March 1946 showed that out of the 885 women surveyed, roughly 10 percent had been sexually assaulted (70 rape survivors and 19 STD-infected individuals). Izumi was aware of the scale of problem he would be faced with. [ 4 ]


The Futsukaichi clinic was started by a group of doctors at Japanese imperial university in  Seoul  and activists [ 5 ]  who after returning to Japan wanted to assist the refugees, with the help of a semi-governmental Repatriate Aid Society aligned with the Japanese foreign ministry.


The staff of the former  Keijō Imperial University  School of Medicine in Seoul had been treating Japanese refugees stranded in Korea, but most were back in Japan by December 1945, and wished to continue their services by treating the displaced repatriates. [ a ]  Also referred to as the "Seoul Group", [ 6 ]  these doctors negotiated how to achieve this purpose with the Repatriate Aid Society  ( 在外同胞援護会 ,  Zaigai dōhō engokai , "The aid society for overseas Japanese") , an extra-departmental body of the  Ministry of Foreign Affairs . As end-result, the Seoul Group became integrated as the Society's medical corp. [ b ] [ 7 ]


The Seoul Group, now known as the Repatriate Aid Society's "medical corp", [ c ]  dispatched physicians to the repatriation ships. The ship doctors observed that most of the evacuees were those who fled Northern Korea, and particularly the girls and women were in miserable states; many had been violated during their flight, and as a result had contracted  sexually transmitted diseases  or had become pregnant, with no measures in place for providing relief. This report was made to the Hakata Regional Repatriation Center  ( 博多引揚援護局 ,  Hakata hikiage engo kyoku ) , a bureau under the  Ministry of Welfare , with recommendation to build a  specialize medical facility for treating sexually-assaulted women, who required disceet abortions. With cooperation from both the Relief Aid Society and the center, the Futsukaichi Rest Home was opened March 25, 1946. [ 8 ]


The facility was located in Futsukaichi, a quiet and secluded hot-spring area near Hakata port in  Fukuoka , [ 9 ] [ 10 ]  where the largest number of repatriates arrived. [ 11 ]  The building was converted from the Musashi Hot Springs Rest House once owned by the prefectural chapter of the " Patriotic Women's Association  [ ja ] . [ 8 ]  It was a wooden, two-storey building with 14 or 15 units available as patient's rooms on the second floor. [ 10 ]


Two doctors and ten nurses (including three midwives) from the Repatriate Aid Society staffed it. [ 12 ]  Similar facilities were placed at the  Kyushu Imperial University  School of Medicine, National Fukuoka Sanatorium,  Kurume Medical School , National Saga Sanatorium, and Nakahara Army Sanatorium in  Saga Prefecture . [ 13 ]


One of the major issues faced by the society was how to make the facility known to the victims. The society handed out flyers in repatriation ships, but carefully selected their wording. The flyer said: "Attention all unfortunate women! If you have been bodily injured by unlawful violence or threat.. and your body is feeling abnormalities.. then we will admit you to a clinic and return you to your home country with a sound body, so please contact the ship's physician". [ d ] [ 7 ]  For women who had already returned to Japan, the group placed advertisement with similar circumloquacious text in influential newspapers. [ 14 ] [ 16 ]


At Hakata port, the Hakata Regional Repatriation Center set up the Hakata Quarantine Station and Feminine Health Advice Center  ( 博多検疫所女子健康相談所 ,  Hakata ken'ekijo joshi kenkosōdansho )  on April 25, 1946, which referred pregnancies (illegal pregnancies) and STD cases to the Futsukaichi or Fukuoka Rest Home. [ 17 ]  The  Ministry of Health and Welfare  issued verbal orders to its workers that all women disembarking at Hakata port were to be screened for pregnancy. [ 18 ] [ e ]


During the facility's one-and-a-half year working period, the medical team carried out an estimated 400–500 abortions. [ 20 ] [ 21 ] [ f ]


Because of the shortage of medication, patients sometimes had to accept operations without  anesthesia [ 24 ]  that was potentially lethal. The rest house operated until fall 1947, just before the Japanese government passed an amendment to the  Eugenic Protection Act  1948 which allowed abortions in cases of rape or on eugenics grounds. [ 25 ]


33°29′17″N   130°30′56″E  /  33.488155°N 130.515649°E  /  33.488155; 130.515649


"Gay bowel syndrome"  is an obsolete classification of various sexually transmitted  rectal  infections observed in  men who have sex with men . It was first used by Dr. Henry L. Kazal in 1976 to describe conditions he observed in his  proctology  practice, which had many gay patients. [ 1 ]  The term has fallen into disuse, as both clinically imprecise and prejudicial: the issues it describes are not specific to gay and bisexual men, limited to the bowel, nor a  medical syndrome .


The term was first used in the pre- HIV  era, by Kazal et al. in 1976. [ 2 ]  After Kazal, the term was used sporadically in medical literature from the 1970s to refer to a complex of  gastrointestinal  symptoms affecting  gay men . [ 3 ]  The term was not specific to any particular disease or infection, and was used clinically to describe  proctitis ,  diarrhea , [ 4 ]  and a variety of other complaints caused by a wide range of infectious organisms. Reported causes include  herpes viruses ,  syphilis ,  gonorrhea ,  chlamydia ,  campylobacter , and  shigellosis , as well as a variety of  protozoal infections . [ 3 ]  The concept of "gay bowel syndrome" was later expanded to include various opportunistic  cancers . Transmission was considered to take place by  anal sex , a fecal-oral route, or both. [ 3 ]  Following the onset of the  AIDS epidemic , the reported incidence of these complaints has declined, likely as a result of  safer sexual practices . [ 5 ]


In 1985, an article in the peer-reviewed journal  Gut  said that "gay bowel syndrome" was not a syndrome, and had limitations in medical use:


The "gay bowel syndrome" was first used to describe not a syndrome, but a list of conditions. The term hides the problems facing the gastroenterologist.  Firstly, the sexual orientation of a patient may not be easily ascertainable in the setting of a general outpatient clinic. Secondly, many infections of the gay bowel are asymptomatic and are missed without full microbiological screening. Thirdly, coinfection is common and the organism isolated may not be causing the symptoms and signs.  Finally, the bowel has limited and non-specific clinical and histopathological responses to many infections. [ 6 ]


A 1997 article in the  Journal of Homosexuality  argued that use of the term should be abandoned:


It is apparent that Gay Bowel Syndrome is an essentialized category of difference that is neither gay-specific, confined to the bowel, nor a syndrome. The use and diagnosis of Gay Bowel Syndrome must be abandoned. [ 7 ]


The term was withdrawn as "outdated" by the Canadian Association of Gastroenterologists in 2004. [ 8 ]  Activist Michael Petrelis said "it is very much a defamation to say ‘gay bowel syndrome', when what they’re really talking about is parasites", and Marty Algaze of the  Gay Men's Health Crisis  argued: "Sickle cell  anemia  is primarily seen in African Americans, but would you call it African American anemia? People would never accept that." [ 8 ]


The U.S.  Centers for Disease Control  confirmed the term was already informal and no longer in use by 2005. [ 9 ]


The 2009  McGraw-Hill Manual of Colorectal Surgery  states that "gay bowel syndrome" is considered obsolete and derogatory:


Coined in the pre-HIV era, the term "gay bowel syndrome" comprised a rather unselective  potpourri  of unusual anorectal and GI symptoms experienced by homosexual males... with better understanding of the underlying causes, this term is outdated: the derogatory terminology should be abandoned and more specific entities and terms recognized and used. [ 10 ]


Gay activist  and author  Michael Scarce  criticized the concept of "gay bowel syndrome" in his book  Smearing the Queer: Medical Bias in the Health Care of Gay Men  (1999), saying that "gay bowel syndrome has been, and remains today, a powerful tool for the specific surveillance, regulation, definition, medicalization, identification, and fragmentation of gay men's bodies." [ 11 ]  Scarce's work has been cited in the  Journal of the American Medical Association  with a positive review. [ 12 ]


General paresis , also known as  general paralysis of the insane (GPI) ,  paralytic dementia , or  syphilitic paresis  is a severe  neuropsychiatric  disorder, classified as an  organic mental disorder , and is caused by late-stage  syphilis  and the chronic  meningoencephalitis  and  cerebral atrophy  that are associated with this late stage of the disease when left untreated. GPI differs from mere  paresis , as mere paresis can result from multiple other causes and usually does not affect cognitive function. Degenerative changes caused by GPI are associated primarily with the frontal and temporal lobar cortex.  The disease affects approximately 7% of individuals infected with syphilis, and is far more common in developing countries where fewer options for timely treatment are available. It is more common among men.


GPI was originally considered to be a type of madness due to a dissolute character, when first identified in the early 19th century. The condition's connection with syphilis was discovered in the late 1880s.  Progressively, with the discovery of organic arsenicals such as  Salvarsan  and  Neosalvarsan  (1910s), the development of  pyrotherapy  (1920s), and the widespread availability and use of  penicillin  in the treatment of syphilis (1940s), the condition was rendered avoidable and curable.  Prior to this, GPI was inevitably fatal, and it accounted for as much as 25% of the primary diagnoses for residents in public psychiatric hospitals.


Symptoms of the disease first appear from 10 to 30 years after infection. Incipient GPI is usually manifested by  neurasthenic  difficulties, such as fatigue, headaches, insomnia, dizziness, etc. As the disease progresses, mental deterioration and personality changes occur. Typical symptoms include loss of social inhibitions, asocial behavior, gradual impairment of judgment, concentration and short-term memory,  euphoria ,  mania ,  depression , or  apathy . Subtle shivering, minor defects in speech and  Argyll Robertson pupil  may become noticeable.


Delusions , common as the illness progresses, tend to be poorly systematized and absurd. They can be grandiose, melancholic, or paranoid. These delusions include ideas of great wealth, immortality, thousands of lovers, unfathomable power, apocalypsis, nihilism, self-guilt, self-blame, or bizarre hypochondriacal complaints. Later, the patient experiences  dysarthria ,  intention tremors ,  hyperreflexia ,  myoclonic  jerks, confusion, seizures and severe muscular deterioration. Eventually, the paretic dies bedridden,  cachectic  and completely disoriented, frequently in a state of  status epilepticus .


The diagnosis could be differentiated from other known psychoses and dementias by a characteristic abnormality in eye pupil reflexes ( Argyll Robertson pupil ), and, eventually, the development of muscular reflex abnormalities,  seizures , memory impairment ( dementia ) and other signs of relatively pervasive neurocerebral deterioration. Definitive diagnosis is based on the analysis of cerebrospinal fluid and tests for syphilis.


Although there were recorded cases of remission of the symptoms, especially if they had not passed beyond the stage of psychosis, these individuals almost invariably experienced relapse within a few months to a few years.  [ citation needed ]  Otherwise, the patient was seldom able to return home because of the complexity, severity and unmanageability of the evolving symptom picture. Eventually, the patient would become completely incapacitated, bed ridden, and would die, the process taking about three to five years on average.


While retrospective studies have found earlier instances of what may have been the same disorder, the first clearly identified examples of paresis among the insane were described in Paris after the  Napoleonic Wars . General paresis of the insane was first described as a distinct disease in 1822 by  Antoine Laurent Jesse Bayle . General paresis most often struck people (men far more frequently than women) between 20 and 40 years of age. By 1877, for example, the superintendent of an asylum for men in New York reported that in his institution this disorder accounted for more than 12% of admissions and more than 2% of deaths.


Originally, the cause was believed to be an inherent weakness of character or constitution. While  Friedrich von Esmarch  and the psychiatrist  Peter Willers Jessen (junior)  [ de ]  had asserted as early as 1857 that  syphilis  caused general paresis (progressive Paralyse), [ 1 ]  progress toward the general acceptance by the medical community of this idea was only accomplished later by the eminent 19th century syphilographer  Jean Alfred Fournier  (1832—1914).  In 1913 all doubt about the syphilitic nature of paresis was finally eliminated when  Hideyo Noguchi  and  J. W. Moore  demonstrated the syphilitic  spirochaetes  in the brains of paretics.


In 1917  Julius Wagner-Jauregg  discovered that  malaria therapy  (in this case, medical induction of a fever) involving  infecting paretic patients  with  malaria  could halt the progression of general paresis. He won a  Nobel Prize  for this discovery in 1927. After  World War II  the use of  penicillin  to treat syphilis made general paresis a rarity: even patients manifesting early symptoms of actual general paresis were capable of full recovery with a course of penicillin.  The disorder is now virtually unknown outside  developing countries , and even there the epidemiology is substantially reduced.


Some notable cases of general paresis:


Creutzfeldt–Jakob disease


A  genital ulcer  is an open sore located on the genital area, which includes the vulva, penis, perianal region, or anus. Genital ulcers are most commonly caused by infectious agents (fungal infections, secondary bacterial infections, or  sexually transmitted infections  such as  genital herpes ,  syphilis  or  chancroid ). However, this is not always the case, as a genital ulcer may have noninfectious causes as well. [ 1 ]


A genital ulcer may be located on the vulva, penis, perianal region, or anus. Globally, the incidence of genital ulcers is estimated to be approximately 20 million cases annually. [ 2 ]  The most likely cause of a genital ulcer varies depending on the characteristics of a population and location. The most common cause of genital ulcers in the United States is herpes simplex infections, with syphilis the second most common cause, and chancroid the third. [ 3 ]  These common causes of genital ulcer disease (HSV-1, HSV-2 and treponema pallidum) can all be efficiently transmitted through oral sex, [ 1 ]  as well as anal and vaginal sex.


Important signs associated with genital ulcers that may assist in the diagnosis of the cause of the genital ulcer may include the presence of tender or non-tender enlarged lymph nodes in the groin area, a painful or non-painful genital ulcer, or the presence of vesicular lesions, which are small, painful, elevated blisters. [ citation needed ]


The most common causes of a genital ulcer include infectious agents, with sexually transmitted infections being the most common, but which can also include fungal infections and secondary bacterial infections. [ 2 ]  While infectious agents are the most common cause, a genital ulcer may also be the result of non-infectious causes such as  Behcet's syndrome ,  lupus , or  psoriasis . [ 4 ]


Since it is difficult to determine a cause of a genital ulcer from history, examination, and population characteristics alone, further testing is often needed. The most common diagnostic tools used are targeted towards the most common etiologies of genital ulcers: syphilis (syphilis serology,  PCR  testing, or  dark-field  examination), herpes simplex virus (PCR, culture, or type specific HSV  antibodies ), and haemophilus ducreyi (culture on special media currently not widely available in most hospital systems) if the individual is in a known endemic region. [ 3 ]  Further diagnostic tools such as a biopsy or culture are often utilized if ulcers appear unusual or do not respond as expected to therapy. [ 1 ]


Since genital ulcers are often infectious in origin, there is an increased risk of acquiring HIV in a HIV negative patient through viral introduction through the open sore [ 5 ] [ 6 ]  Conversely, there is an increased risk of HIV transmission through increased shedding of viral HIV in the presence of a genital ulcer in a patient with a history of HIV. [ 6 ] [ 5 ]  Available studies did not give enough evidence that treatment of genital ulcer reduce the sexual infection of HIV. However, genital ulcer need to be treated regardless of HIV infection probability of the treatment. [ 7 ]  The CDC recommends testing for HIV in any individual presenting for a genital ulcer who does not already have a history of HIV. [ 3 ]


Risk factors for sexually transmitted genital ulcers are similar to the risk factors for most sexually transmitted infections which include multiple sex partners, alcohol, illicit drug use, homelessness, poverty, inmates, men who have sex with men, sexually active teenagers, sexual contact without contraceptive use, and unstable housing. [ 8 ]
The most common cause of genital ulcers in the North America and Western Europe are the result of HSV or syphilis infections, while the most common cause in other parts of the world is chancroid. [ 9 ] [ 4 ]  Most sexually active adolescents with genital ulcers have a herpes simplex virus infection, more commonly type 2. [ 4 ]  Meanwhile, according to 2017 CDC reports, syphilis is more common in men who have sex with men populations although rates of syphilis have been rising in heterosexual men and women in the United States. [ 10 ]  Following syphilis and genital herpes infections, a chancroid is the third most common cause but tends to occur in focused outbreaks over time. [ 4 ]  While rates of H. ducreyi infection seem to be declining according to a 2017 report, it is possible this may be due to lack of testing since H. ducreyi requires a very specialized culture medium which is not commonly available. [ 3 ] [ 10 ]  Less common causes include lymphogranuloma venereum, which is more common in men who have sex with men, and granuloma inguinale, which is more common in tropical regions globally. rather than in the United States. [ 4 ]


Genital ulcers are not strictly a sign of a sexually transmitted illness, although non-infectious sources are significantly more infrequent in comparison. The most common non-infectious sources of genital ulcers are first Behcet's disease, and second drug reaction. [ 2 ]


Behcet's syndrome  is a chronic systemic vasculitis infection that is defined by recurrent oral and genital aphthous ulcers but can also affect many other organ systems, such as the eyes, ears, nervous system, heart, lungs, joints, and intestines. [ 11 ]  Behcet's syndrome commonly presents in the 30-40 age range [ 11 ]  and is more common in the Middle East and Asia. [ 12 ]  There is a familial component to Behcet's syndrome since it has associations with the HLA-B51 gene. [ 11 ]


Causes of drug induced genital ulcers take the form of  Stevens–Johnson syndrome ,  toxic epidermal necrolysis ,  erythema multiforme , and  fixed drug eruptions  in response to a diverse list of medications. [ 11 ]  Stevens–Johnson syndrome and toxic epidermal necrolysis are more likely than erythema multiforme to have genital manifestations although all present with a toxic appearing patient. [ 11 ]  A fixed drug eruption in comparison does not present as a toxic appearing patient but rather single or multiple erythematous patches that vary in size and shape which eventually turn dark brown in color and become itchy. [ 11 ]  The defining characteristic is that these drug eruptions appear in the same location each time the offending medication is used, and will resolve on their own. [ 11 ]


Other potential causes of non-infectious genital ulcers are diverse, but can include sexual trauma,  Lipschutz ulcers , inflammatory bowel diseases such as Crohn's disease, lichen planus, lichen sclerosis, and immunobullous disease such as pemphigous vulgaris, since bullous pemphigoid is less likely to occur on the genitals. [ 11 ]  Cancers of the vulva and penis, with the most common subtype being squamous cell carcinoma, can also present as genital ulcers, but leukemias such as chronic lymphocytic leukemia and acute promyelotic leukemia have also been identified. [ 11 ]


Even lesser common etiologies of genital ulcers include fungal infection, secondary bacterial infections, and parasitic infections. [ 11 ] [ 4 ]


Fungal infections are rare causes of genital ulcers, but  candida albicans  infection is typically the most common source, and is more prevalent in patients with a history of diabetes mellitus, chronic steroid use, or other immunodeficiencies. [ 11 ]  There have also been rare case reports of paracoccidioidomycosis, zygomycosis and histoplasmosis infections causing genital ulcers. [ 11 ]


Parasitic infections such as  amoebiasis  and  leishmaniasis  can present in cutaneous form in the genital regions. This can be confused with a sexually transmitted infection or sepsis due to their tendency to present with additional systemic symptoms. [ 11 ]


Genital  tuberculosis  can also present as a genital ulcer, either in the form of cutaneous tuberculosis from a systemic infection, or a primary tuberculosis chancre at the site of inoculation via direct genital contact with infected sputum. [ 11 ]  Cutaneous tuberculosis typically presents initially as red or yellow nodules that eventually break down to form soft, painful, and roughly circular ulcers, which as a rule are covered in a pseudomembrane. [ 11 ]  Primary tuberculosis chancre, on the other hand, often presents as a painless ulcer with well defined edges that appears rather nonspecific. [ 11 ]


A  gumma  (plural  gummata  or  gummas ) is a soft, non-cancerous growth resulting from the tertiary stage of  syphilis  (and  yaws [ 1 ] ).


It is a form of  granuloma . [ 2 ]  Gummas are most commonly found in the  liver  ( gumma hepatis ), but can also be found in brain, heart, skin, bone, testis, and other tissues, leading to a variety of potential problems including  neurological  disorders or  heart valve  disease.


Gummas have a firm, necrotic center surrounded by inflamed tissue, which forms an amorphous proteinaceous mass.  The center may become partly  hyalinized .
These central regions begin to die through  coagulative necrosis , though they also retain some of the structural characteristics of previously normal tissues, enabling a distinction from the granulomas of  tuberculosis  where  caseous necrosis  obliterates preexisting structures.  Other histological features of gummas include an  intervening zone  containing  epithelioid  cells with indistinct borders and multinucleated  giant cells , and a  peripheral zone  of  fibroblasts  and  capillaries .  Infiltration of  lymphocytes  and  plasma cells  can be seen in the peripheral zone as well.  With time, gummas eventually undergo fibrous degeneration, leaving behind an irregular scar or a round fibrous nodule. [ citation needed ]


It is restricted to  necrosis  involving  spirochaetal  infections that cause  syphilis .  Growths that have the appearance of gummas are described as gummatous. [ 3 ]


In syphilis, the gumma is caused by a reaction to spirochaete bacteria in the tissue.
It appears to be the human body's way to slow down the action of this bacteria; it is a unique immune response that develops in humans after the immune system fails to kill off syphilis. [ citation needed ]


The formation of gummata is rare in developed countries, but common in areas that lack adequate medical treatment. [ citation needed ]


Syphilitic gummas are found in most but not all cases of tertiary syphilis, and can occur either singly or in groups.  Gummatous lesions are usually associated with long-term syphilitic infection; however, such lesions can also be a symptom of benign late syphilis. [ citation needed ]


Hepatitis B  is an  infectious disease  caused by the  hepatitis B virus  (HBV) that affects the  liver ; [ 1 ] [ 6 ]  it is a type of  viral hepatitis . [ 7 ]  It can cause both acute and  chronic infection . [ 1 ]


Many people have no symptoms during an initial infection. For others, symptoms may appear 30 to 180 days after becoming infected and can include a rapid onset of sickness with  nausea ,  vomiting ,  yellowish skin ,  fatigue , yellow urine, and  abdominal pain . [ 1 ]  Symptoms during acute infection typically last for a few weeks, though some people may feel sick for up to six months. [ 8 ]  Deaths resulting from acute stage HBV infections are rare. [ 9 ]  An HBV infection lasting longer than six months is usually considered chronic. [ 1 ]  The likelihood of developing chronic hepatitis B is higher for those who are infected with HBV at a younger age. About 90% of those infected during or shortly after birth develop chronic hepatitis B, [ 8 ]  while less than 10% of those infected after the age of five develop chronic cases. [ 5 ]  Most of those with chronic disease have no symptoms; however,  cirrhosis  and  liver cancer  eventually develop [ 2 ]  in about 25% of those with chronic HBV. [ 4 ]


The virus is transmitted by exposure to infectious  blood  or  body fluids . [ 4 ]  In areas where the disease is  common ,  infection around the time of birth  or from contact with other people's blood during childhood are the most frequent methods by which hepatitis B is acquired. [ 4 ]  In areas where the disease is rare,  intravenous drug use  and  sexual intercourse  are the most frequent  routes of infection . [ 4 ]  Other risk factors include working in healthcare,  blood transfusions ,  dialysis , living with an infected person, travel in countries with high infection rates, and living in an institution. [ 4 ] [ 5 ]   Tattooing  and  acupuncture  led to a significant number of cases in the 1980s; however, this has become less common with improved sterilization. [ 10 ]  The  hepatitis B  viruses cannot be spread by holding hands, sharing eating utensils, kissing, hugging, coughing, sneezing, or breastfeeding. [ 5 ]  The infection can be diagnosed 30 to 60 days after exposure. [ 4 ]  The diagnosis is usually confirmed by testing the blood for parts of the virus and for  antibodies  against the virus. [ 4 ]  It is one of five main  hepatitis  viruses:  A , B,  C ,  D , and  E . [ 11 ]  During an initial infection, care is based on a person's symptoms. [ 4 ]  In those who develop chronic disease,  antiviral medication  such as  tenofovir  or  interferon  may be useful; however, these drugs are expensive. [ 4 ]   Liver transplantation  is sometimes recommended for cases of cirrhosis or  hepatocellular carcinoma . [ 4 ]


Hepatitis B infection has been preventable by  vaccination  since 1982. [ 4 ] [ 12 ]  As of 2022, the hepatitis B vaccine is between 98% and 100% effective in preventing infection. [ 1 ]  The vaccine is administered in several doses; after an initial dose, two or three more vaccine doses are required at a later time for full effect. [ 1 ]  The  World Health Organization  (WHO) recommends infants receive the vaccine within 24 hours after birth when possible. [ 1 ]  National programs have made the hepatitis B vaccine available for infants in 190 countries as of the end of 2021. [ 13 ] [ 14 ]  To further prevent infection, the WHO recommends testing all donated blood for hepatitis B before using it for transfusion. Using antiviral prophylaxis to prevent mother-to-child transmission is also recommended, as is following safe sex practices, including the use of  condoms . [ 1 ]  In 2016, the WHO set a goal of eliminating viral hepatitis as a threat to global  public health  by 2030. Achieving this goal would require the development of therapeutic treatments to cure chronic hepatitis B, as well as preventing its transmission and using vaccines to prevent new infections. [ 15 ] [ 16 ] [ 17 ]


An estimated 296 million people, or 3.8% of the global population, had chronic hepatitis B infections as of 2019. Another 1.5 million developed acute infections that year, and 820,000 deaths occurred as a result of HBV. [ 1 ]  Cirrhosis and liver cancer are responsible for most HBV-related deaths. [ 18 ]  The disease is most prevalent in Africa (affecting 7.5% of the continent's population) and in the Western Pacific region (5.9%). [ 19 ]  Infection rates are 1.5% in Europe and 0.5% in the Americas. [ 19 ]  According to some estimates, about a third of the world's population has been infected with hepatitis B at one point in their lives. [ 18 ]  Hepatitis B was originally known as "serum hepatitis". [ 20 ]


Acute infection with  hepatitis B  virus is associated with acute viral  hepatitis , an illness that begins with general ill-health, loss of appetite, nausea, vomiting, body aches, mild fever, and dark urine, and then progresses to development of  jaundice . The illness lasts for a few weeks and then gradually improves in most affected people. A few people may have a more severe form of liver disease known as  fulminant hepatic failure  and may die as a result. The infection may be entirely asymptomatic and may go unrecognized. [ 21 ]


Chronic infection with  hepatitis B  virus may be asymptomatic or may be associated with chronic inflammation of the liver (chronic hepatitis), leading to  cirrhosis  over a period of several years. This type of infection dramatically increases the incidence of  hepatocellular carcinoma  (HCC; liver cancer). Across Europe, hepatitis B and C cause approximately 50% of hepatocellular carcinomas. [ 22 ] [ 23 ]  Chronic carriers are encouraged to avoid consuming  alcohol  as it increases their risk for  cirrhosis  and liver cancer.  Hepatitis B  virus has been linked to the development of  membranous glomerulonephritis  (MGN). [ 24 ]


Symptoms outside of the liver are present in 1–10% of HBV-infected people and include  serum-sickness–like syndrome ,  acute necrotizing vasculitis  ( polyarteritis nodosa ), membranous glomerulonephritis, and  papular acrodermatitis of childhood  ( Gianotti–Crosti syndrome ). [ 25 ] [ 26 ]  The serum-sickness–like syndrome occurs in the setting of acute  hepatitis B , often preceding the onset of jaundice. [ 27 ]  The clinical features are fever,  skin rash , and  polyarteritis . The symptoms often subside shortly after the onset of jaundice but can persist throughout the duration of acute  hepatitis B . [ 28 ]  About 30–50% of people with acute necrotizing vasculitis (polyarteritis nodosa) are HBV carriers. [ 29 ]  HBV-associated  nephropathy  has been described in adults but is more common in children. [ 30 ] [ 31 ]  Membranous glomerulonephritis is the most common form. [ 28 ]  Other immune-mediated  hematological  disorders, such as essential mixed  cryoglobulinemia  and  aplastic anemia  have been described as part of the extrahepatic manifestations of HBV infection, but their association is not as well-defined; therefore, they probably should not be considered etiologically linked to HBV. [ 28 ]


Transmission of  hepatitis B  virus results from exposure to infectious blood or body fluids containing blood. HBV is 50 to 100 times more infectious than  human immunodeficiency virus (HIV) . [ 32 ]  HBV can be transmitted through several routes of infection. In  vertical transmission , HBV is passed from mother to child (MTCT) during childbirth. [ 1 ]  Without intervention, a mother who is positive for  HBsAg  has a 20% risk of passing the infection to her offspring at the time of birth. This risk is as high as 90% if the mother is also positive for  HBeAg . [ citation needed ]


Early life horizontal transmission can occur through bites, lesions, certain sanitary habits, or other contact with secretions or saliva containing HBV. [ 33 ] [ 34 ]  Adult horizontal transmission is known to occur through  sexual contact , [ 35 ]   blood transfusions  and transfusion with other human blood products, [ 36 ]   re-use of contaminated needles  and syringes. [ 37 ]  Breastfeeding after proper immunoprophylaxis does not appear to contribute to mother-to-child-transmission (MTCT) of HBV. [ 38 ]


Hepatitis B  virus (HBV) is a member of the  hepadnavirus family . [ 39 ]  The virus particle ( virion ) consists of an outer  lipid  envelope and an  icosahedral   nucleocapsid  core composed of core  protein . These virions are 30–42 nm in diameter. The nucleocapsid encloses the viral DNA and a DNA polymerase that has  reverse transcriptase  activity. [ 40 ]  The outer envelope contains embedded proteins that are involved in viral binding of, and entry into, susceptible cells. The virus is one of the smallest enveloped animal viruses.  The 42 nm virions, which are capable of infecting liver cells known as  hepatocytes , are referred to as "Dane particles". [ 41 ]  In addition to the Dane particles, filamentous and spherical bodies lacking a core can be found in the serum of infected individuals. [ 42 ]    These particles are not infectious and are composed of the lipid and protein that forms part of the surface of the virion, which is called the surface antigens ( HBsAg ), and is produced in excess during the life cycle of the virus. [ 43 ]