On 6 October 2007,  Craig Venter  announced that a team of scientists led by Nobel laureate  Hamilton Smith  at the J. Craig Venter Institute had successfully constructed  synthetic DNA  with which they planned to make the first synthetic genome. Reporting in  The Guardian , Venter said that they had stitched together a DNA strand containing 381 genes, consisting of 580,000 base pairs, based on the genome of  M. genitalium . [ 59 ]  On 24 January 2008, they announced the successful creation of a synthetic bacterium, which they named  Mycoplasma genitalium  JCVI-1.0 (the name of the strain indicating J. Craig Venter Institute with its specimen number). [ 60 ]  They synthesised and assembled the complete 582,970-base pair genome of the bacterium. The final stages of synthesis involved cloning the DNA into the bacterium  E. coli  for nucleotide production and sequencing. This produced large fragments of approximately 144,000 base pairs or 1/4th of the whole genome. Finally, the products were cloned inside the yeast  Saccharomyces cerevisiae  to synthesize the 580,000 base pairs. [ 61 ] [ 62 ]  The molecular size of the synthetic bacterial genome is 360,110  kilodaltons  (kDa). Printed in 10-point font, the letters of the genome cover 147 pages. [ 63 ]


On 20 July 2012,  Stanford University  and the J. Craig Venter Institute announced successful simulation of the complete life cycle of a  Mycoplasma genitalium  cell, in the journal  Cell . [ 64 ]  The entire organism is modeled in terms of its molecular components, integrating all cellular processes into a single model. Using object oriented programming to model the interactions of 28 categories of molecules, including DNA, RNA, proteins, and metabolites, and running on a 128 computer Linux cluster, the simulation takes 10 hours for a single  M. genitalium  cell to divide once—about the same time the actual cell takes—and generates half a gigabyte of data. [ 65 ]


The discovery of  Protein M , a protein produced by  M. genitalium , was announced in February 2014. [ 66 ]  The protein was identified during investigations on the origin of  multiple myeloma , a B-cell hematologic neoplasm. To understand the long-term  Mycoplasma  infection, it was found that  antibodies  from multiple myeloma patients' blood were recognised by  M. genitalium . The antibody reactivity was due to a protein, designated Protein M, that is chemically responsive to all types of human and nonhuman antibodies available. The protein is about 50 kDa in size, and composed of 556 amino acids. [ 67 ]


Mgen evolved from a gram-positive ancestor that was clostridium-like but has lost the genes to code for the enzymes involved in de novo nucleic acid synthesis, amino acid synthesis, and synthesis of fatty acids. [ 68 ]  This means that Mgen needs the host's growth factors to keep reproducing. Although Mgen has abilities that help it adhere to cells, it is still unknown how the bacteria can maintain an infection inside the epithelial cells of the ectocervix and vagina when shedding of the apical layer of cells occur. The organism's ability to have adhesion to host cells relies of two proteins, P110 and P140. Adhesion is an important step in beginning an infection in a cell and Mgen can adhere to spermatozoa, erythrocytes, and epithelial cells. The terminal organelle relies on these proteins as well because without them the organelle was not present. The segmented pair plates of Mgen  [ vague ]  is a core of dense electrons which is anchored to the cell membrane. The end of this core is in contact with the wheel complex and the wheel complex contains the proteins MG219, MG200, MG386, and MG491 which aid in the gliding motility of the bacteria. Although Mgen lacks secreted virulence factors, the protein MG186 degrades host nucleic acids due to it being a calcium-dependent membrane-associated nuclease. [ citation needed ]


The exact role of  Mycoplasma hominis  (and to a lesser extent  Ureaplasma ) in regards to a number of conditions related to pregnant women and their (unborn) offspring is controversial. This is mainly because many healthy adults have genitourinary colonization with Mycoplasma, published studies on pathogenicity have important design limitations and the organisms are very difficult to detect. [ 1 ]  The likelihood of colonization with  M. hominis  appears directly linked to the number of lifetime sexual partners [ 2 ]
Neonatal colonization does occur, but only through normal vaginal delivery. Caesarean section appears protective against colonization and is much less common. Neonatal colonization is transient. [ 3 ]


Those with urogenital or extragenital infections caused by  M. hominis  have symptoms similar to other sexually transmitted infections and its presence cannot be determined by its symptoms. The precise role this organism plays in causing disease remains speculative. [ 4 ]  Diagnosis remains a challenge because the organism is difficult to culture in vitro.  PCR-based techniques are still rare outside research scenarios. [ 5 ]
The following conditions have been linked to Mycoplasma hominis: [ citation needed ]


Mycoplasma hominis  is often present in polymicrobial infections. [ 6 ]


If symptomatic, testing is recommended. [ 7 ]  The risk of contracting Mycoplasma infection can be reduced by the following:


Mycoplasmas  have a triple-layered membrane and lack a cell wall. Therefore, mycoplasmas are not affected by  penicillins  and other antibiotics that interfere with the cell wall synthesis. The growth of mycoplasmas in their host is inhibited by other broad-spectrum antibiotics. These broad-spectrum antibiotics inhibit the multiplication of the mycoplasma but does not kill them.  Tetracyclines ,  macrolides ,  ketolides ,  quinolones  are used to treat mycoplasma infections. In addition to the penicillins, mycoplasmas are resistant to  rifampicin . Mycoplasmas may be difficult to eradicate from human or animal hosts or from cell cultures by antibiotic treatment because of resistance to the antibiotic, or because it does not kill the mycoplasma cell. Mycoplasma cells are able to invade the cells of their hosts. [ 9 ]


Neonates, especially if preterm, are susceptible to  M. hominis  infection. [ 10 ]
 Meningoencephalitis  in neonates has been described and M. hominis may be a significant causative agent of  neonatal sepsis  or  meningitis . [ 11 ]
 M. hominis  has been associated with  chorioamnionits . [ 12 ]   M. hominis  is associated with  miscarriage . [ 13 ]


Neonatal infections  are infections of the  neonate  (newborn) acquired during  prenatal development  or within the first four weeks of life. [ 1 ]  Neonatal infections may be contracted by  mother to child   transmission , in the  birth canal  during  childbirth , or after birth. [ 2 ]  Neonatal infections may present soon after delivery, or take several weeks to show symptoms. Some neonatal infections such as  HIV ,  hepatitis B , and  malaria  do not become apparent until much later. Signs and symptoms of infection may include  respiratory distress , temperature instability,  irritability ,  poor feeding ,  failure to thrive , persistent crying and skin rashes.


Risk factors include previous maternal infection,  preterm delivery  (< 37 weeks gestation) and  premature rupture of membranes  (breakage of the  amniotic sac ) which substantially increases the risk of  neonatal sepsis  by allowing passage for bacteria to enter the womb prior to the birth of the infant. Preterm or  low birth weight  neonates are more vulnerable to neonatal infection. While preterm neonates are at a particularly high risk, all neonates can develop infection. Maternal screening for intrapartum infections reduce the risk of neonatal infection. Pregnant women may receive intrapartum antibiotic prophylaxis for prevention of neonatal infection. [ 3 ]


Infant respiratory distress syndrome  is a common complication of neonatal infection, a condition that causes difficulty breathing in preterm neonates. Respiratory distress syndrome can arise following neonatal infection, and this syndrome may have long-term negative consequences. In some instances, neonatal respiratory tract diseases may increase the susceptibility to future respiratory infections and inflammatory responses related to lung disease. [ 4 ]


Antibiotics  can be effective for neonatal infections, especially when the  pathogen  is quickly identified. Instead of relying solely on culturing techniques, pathogen identification has improved substantially with advancing technology; however,  neonate mortality  reduction has not kept pace. In industrialized countries,  treatment  for neonatal infections takes place in the  neonatal intensive care unit  (NICU). Neonatal infection can be distressing to the family and it initiates concentrated effort to treat it by  clinicians . Research to improve treatment of infections and prophylactic treatment of the mother to avoid infections of the infant is ongoing. [ 5 ]


Signs and symptoms of infection include respiratory distress, temperature instability, irritability, failure to thrive, and skin rashes. [ citation needed ]


Early-onset sepsis (EOS), defined as onset of symptoms within 72 hours of life, is generally caused by transmission of  pathogens  from the  female genitourinary system  to the fetus. Pathogens can infect the fetus via  vertical transmission  (direct transmission through the placenta in utero) or infection during delivery as fetus passes through  vaginal canal.


Late-onset sepsis (LOS), defined as onset of symptoms after 72 hours of life, is generally caused by transmission of pathogens from the environment after delivery. Infants requiring intravascular catheters and other invasive procedures are at increased risk for developing LOS. [ 3 ]


There are many etiologies of neonatal infection, including bacterial, viral and fungal pathogens. The source of infectious  bacteria  and other pathogens is often the  maternal   gastrointestinal  and  genitourinary tract . Many of the maternal infections with these organisms are  asymptomatic  in the mother. Other maternal infections that may be transmitted to the infant in  utero  or during birth are bacterial and viral  sexually transmitted infections . The infant's ability to resist infection is limited by its immature  immune system . In addition, the immune system of the neonate may respond in ways that can create problems that complicate treatment, such as the release of  inflammatory chemicals . Congenital defects of the immune system also affect the infants ability to fight off the infection. [ 6 ]


Bacteria found in the maternal gastrointestinal or gastrourinary tracts can commonly lead to neonatal infection. Bacterial infections may present as fetal distress at birth (including signs of tachycardia, temperature instability or difficulty breathing), neonatal sepsis, or neonatal meningitis. Infections that develop during NICU admissions are more commonly coagulase-negative staphylococci, especially in infants with indwelling catheters. Infections that develop one month after the birth of the infant are more likely due to  gram-positive bacteria  and  coagulase positive staphylococci . [ 7 ]     ...


Group B streptococcus  (GBS), also named  Streptococcus agalactiae , is a bacteria typically identified as the cause of the majority of early-onset infections in the neonate. GBS is an encapsulated gram-positive cocci that colonizes the gastrointestinal and genital tracts of pregnant women. Maternal infections are usually asymptomatic. This pathogen is  vertically transmitted  (transmitted directly from the mother's vagina into the infant's amniotic fluid after onset of labor). Due to the high prevalence of GBS, routine screening for the bacteria occurs during pregnancy. If the bacteria is found in the maternal GI / GU tract, mothers will receive IV antibiotic (usually penicillin or ampicillin). [ 8 ]


Escherichia coli  is an encapsulated gram-negative bacilli that may cause neonatal infections due to its high prevalence in the GI and GU tracts of pregnant patients. With the advances in preventing group B streptococcus infections, β-lactam-resistant  Escherichia coli  infections have increased in causing neonatal deaths in very low birthweight and premature infants. Common complications of neonatal E.coli infection include neonatal sepsis and neonatal meningitis. [ 9 ]


Neisseria gonorrhoeae  is a common  sexually transmitted infection  which may be present in pregnant women at time of delivery. This pathogen is usually acquired during delivery, occurring in 30-40% of cases with known maternal infection. Additionally, untreated maternal gonorrhea may increase the risk of  preterm delivery.  The most common manifestation of gonococcal infection in a newborn is  neonatal conjunctivitis , an infection of the eyes that presents with green-yellow  exudate  and eyelid swelling. Without treatment, this infection can lead to permanent  visual impairment . Treatment of  Neisseria gonorrhoeae  conjunctivitis consists of a single dose of  ceftriaxone  (antibiotic). Typically, all neonates (regardless of symptoms or risk factors) receive  erythromycin  ointment applied to both eyes after delivery [ 10 ]


Listeria monocytogenes  is a gram-positive bacilli that can cause infection acquired from  tainted food  and present in the mother. The presence of this pathogen can sometimes be determined by the symptoms that appear as a  gastrointestinal illness  in the mother. The mother acquires infection from ingesting food that contains  animal products  such as  hot dogs ,  unpasteurized   milk ,  delicatessen meats , and  cheese . [ 11 ]


Clostridium tetani  can cause a generalised form of  tetanus  in the neonate. This usually occurs when the mother has not been vaccinated against tetanus and the baby has not acquired passive immunity. The umbilical cord region is the most susceptible. [ 12 ]


Less common bacterial pathogens include  Streptococcus pyogenes ,  Viridans streptococci ,  Streptococcus pneumoniae ,  Haemophilus influenzae , and  Pseudomonas aeruginosa . [ 13 ] [ citation needed ]


Human immunodeficiency virus  (HIV) infection can occur during delivery of the neonate, in utero through mother-to-child transmission or postnatally by way of breastfeeding. Most transmission occurs during delivery. Transmission depends on multiple risk factors, usually centered around the viral load of HIV in the mother. Strategies for reducing transmission of HIV include:


Symptoms of HIV in a child will vary depending on the age of presentation. Common symptoms include  failure to thrive , recurrent infections such as  pneumonia , intermittent diarrhea, swollen lymph nodes and  oral thrush . In infants, diagnostic testing for HIV relies of detection of the virus in the bloodstream. For infants born to HIV-infected mothers, diagnostic testing will be performed within days of delivery, at 1–2 months and at 4–6 months of age. [ 15 ]


Cytomegalovirus (CMV)  is the most common congenital viral infection, usually transmitted through the placenta during pregnancy. Most neonates with congenital CMV infection will not have any symptoms, but a minority of infected newborns will have symptomatic infection. Common symptoms include rash,  microcephaly  (small head),  low birth weight ,  jaundice ,  thrombocytopenia , seizures and  retinitis . Long-term complications of congenital CMV infections may include  sensorineural hearing loss ,  developmental delay , and seizures. Due to high prevalence of disease, CMV is not routinely screened in pregnant patients. [ 16 ]


Herpes simplex virus  (HSV), which commonly causes cold sores and painful genital blisters can cause congenital infection via direct contact with genital tract lesions during delivery. Neonatal HSV may be classified into three categories based on symptom presentation:


Maternal infection with  rubella virus  during pregnancy can lead to  congenital rubella syndrome . The risk of congenital infection is highest during the first trimester (< 12 weeks). Risk of congenital rubella is increased among immigrant women from countries without adequate vaccination programs. Common symptoms include  cataracts ,  hearing impairment ,  developmental delay  and  congenital heart disease. [ 18 ]


Zika virus is an arthropod-borne virus transmitted by  mosquitos , and infection during pregnancy can lead to severe congenital abnormalities in a newborn. Congenital infection can lead to  fetal growth restriction  and CNS abnormalities, including  microcephaly ,  ventriculomegaly  and intracranial calcifications. [ 19 ]


There are five liver specific viruses (hepatitis A, B, C, D, E) that could potentially harm the mother and child. Acute hepatitis A virus or acute hepatitis E virus infection present the greatest risk to maternal and fetal health and increased risk of adverse pregnancy outcomes. Hepatitis B, C and D virus present a risk of mother to child transmission but are dependent on the severity of the underlying disease in the mother. However, hepatitis B virus is the major cause of neonatal infection. [ 20 ]


Other viral infections, such as  respiratory syncytial virus  (RSV),  metapneumovirus  (hMPV),  rhinovirus ,  parainfluenza  (PIV), and  human coronavirus  in the neonatal period are associated with recurrent  wheezing  in later childhood. [ citation needed ]


In very low birth weight infants (VLBWI), systemic fungus infection is a  hospital-acquired infection  with serious consequences. The pathogens are usually  Candida albicans  and  Candida parapsilosis . A small percentage of fungal infections are caused by  Aspergillus ,  Zygomycetes ,  Malassezia , and  Trichosporon . [ 22 ] [ 23 ]  Infection is usually late-onset. Up to 9% of VLBWI with birth weights of <1,000 g develop these fungus infections leading to sepsis or meningitis. As many as one-third of these infants can die. Candidiasis is associated with retinopathy, prematurity and negative neurodevelopmental consequences. Candida can colonize the gastrointestinal tract of low birthweight infants (LBI). This gastrointestinal colonization is often a precursor to a more serious invasive infection. The risk of serious candida infection increases when multiple factors are present. These are:  thrombocytopenia , the presence of candidal dermatitis, the use of systemic steroids, birth weights of <1,000 g, presence of a central catheter, postponing enteral feeding, vaginal delivery, and the amount of time broad-spectrum antibiotics were given. [ 23 ]


Infants born with  malaria  can be infected with a variety of  species ;  Plasmodium vivax ,  Plasmodium malariae ,  Plasmodium ovale , and  Plasmodium falciparum . In most instances of congenital malaria is caused by  P. vivax  and  P. falciparum . Women living in areas where malaria is prevalent and common are repeatedly exposed to malaria. In response to maternal infection, mothers develop antimalarial  antibodies . It is probable that the antibodies present in the mother offers protection for the baby. Bacterial infection can develop with malaria. [ 22 ]


Infants that are infected by the protozoan  Toxoplasma gondii  in utero can be born with  chorioretinitis  or ocular toxoplasmosis. Globally, it is the most common cause of infections of the back of the eye. (posterior segment). The most common sign is decreased vision in one eye. Other signs and symptoms may appear after the neonatal period and include: chorioretinitis development later in life, intracranial calcification hydrocephalus or central nervous system abnormalities. [ 24 ]


Preterm neonates are at greater risk of infection, including severe complications such as sepsis and meningitis. Preterm neonates usually have ineffective immune systems, due to decreased IgG antibodies and decreased complement activation. Additionally, preterm neonates require longer hospital admissions, including the placement of invasive devices that increase risk of infection. [ citation needed ]


Maternal risk factors for neonatal infection include:


Inflammation accompanies infection and is likely to complicate  treatment  and recovery. Inflammation is linked to reduced growth of the  lungs  of the premature baby. [ 26 ]


The recent identification of the presence of  microorganisms  in maternal-infant body fluids that were previously thought to be sterile has provided one explanation for the presence of the inflammatory response in both the mother and infant. Sixty-one percent of pregnant women with  chorioamnionitis , or inflammation of the  amniotic fluid , were found to be infected by microorganisms. Often,  more than one  pathogen was present. In fifteen percent of pregnant women inflammation was still evident even though there was no evidence of pathogens. This may indicate that there are other causes. A high percentage, 51% to 62%, of pregnant women who had chorioamnionitis also had inflammation of the  placenta . [ 26 ]


Diagnosis  of infection is based upon the recovery of the pathogen or pathogens from the typically  sterile  sites in the mother or the baby. Unfortunately, as many half of pregnant women are asymptomatic with a gonorrhea infection and other sexually transmitted infections. [ 27 ] [ 28 ] [ 29 ]  Samples are obtained from  urine ,  blood  or  cerebrospinal fluid . Diagnosis of infection can also be aided by the use of more nonspecific tests such as determining the total  white blood cell  count,  cytokine  levels and other blood tests and  signs . [ 30 ]


Symptoms and the isolation of the virus pathogen the upper respiratory tract is diagnostic. Virus identification is specific immunologic methods and PCR. The presence of the virus can be rapidly confirmed by the detection of the virus antigen. The methods and materials used for identifying the RSV virus has a specificity and sensitivity approaching 85% to 95%. Not all studies confirm this sensitivity. Antigen detection has comparatively lower sensitivity rates that approach 65% to 75%. [ 35 ]


Congential malaria has its own set of signs:


Neonatal sepsis of the newborn is an infection that has spread through the entire body. The inflammatory response to this systematic infection can be as serious as the infection itself. [ 26 ]  In infants that weigh under 1500 g,  sepsis  is the most common cause of death. Three to four percent of infants per 1000 births contract sepsis. The mortality rate from sepsis is near 25%. [ 36 ]  Infected sepsis in an infant can be identified by culturing the blood and spinal fluid and if suspected, intravenous antibiotics are usually started. Lumbar puncture is controversial because in some cases it has found not to be necessary while concurrently, without it estimates of missing up to one third of infants with meningitis is predicted. [ 30 ]


To reduce neonatal infection, screening of pregnant women for HIV, hepatitis B, and syphilis, is available in the UK and the United States. [ 37 ] [ 38 ]


Treatment with a vaginal antibiotic wash prior to birth does not prevent infection with group B streptococcus bacteria (GBS). [ 31 ] [ 39 ]  Treatment with vaginal chlorhexidine prior to birth does not prevent neonatal infections. [ 40 ]


Because GBS bacteria can colonize the lower reproductive tract of 30% of women, typically pregnant women are tested for this pathogen from 35 to 37 weeks of pregnancy. Before delivery treatment of the mother with antibiotics reduces the rate of neonatal infection. [ 31 ]  Prevention of the infection of the baby is done by treating the mother with penicillin. Since the adoption of this prophylactic treatment, infant mortality from GBS infection has decreased by 80%. [ 36 ]


Mothers with symptomatic  genital herpes  and who are treated with antiviral prophylaxis are less prone to have an active, symptomatic case at the time of birth and it may be able to reduce the risk of passing on HSV during birth. Cesarean delivery reduces the risk of infection of the infant. [ 41 ]


Breastfeeding  has been shown to protect the neonate from some infections. [ 42 ] [ 43 ] [ 44 ] [ 45 ] [ 46 ]   [ excessive citations ]  Breast milk protects against necrotizing  enterocolitis . [ 47 ]


Hepatitis A, B, and D are preventable via vaccination. Hepatitis A can be prevented by immunization against HAV, while Hepatitis B and D can both be prevented by immunization against HBV. [ 20 ]


The Hepatitis B vaccination is among the first two injections a newborn receives. [ 48 ]  The other is vitamin K to prevent  vitamin K deficiency bleeding . [ 49 ]  In cases where the pregnant woman is positive for hepatitis B, the baby will receive an additional dose of hepatitis B immunoglobulin in addition to the hepatitis B vaccine to prevent transmission of the disease from mother to baby. [ 50 ]  Prevention of hepatitis B is crucial as there is no currently no cure. [ 51 ]


In general, in an unvaccinated individual, the viral hepatitis family causes liver damage due to a cell-mediated response via cytotoxic lymphocytes. [ 52 ]  Acute viral hepatitis can lead to jaundice, elevated bilirubin, elevated liver enzymes (aspartate transaminase, alanine transaminase, and alkaline phosphatase), and flu-like symptoms. [ 52 ]  Importantly, acute neonatal HBV infections progress to chronic Hepatitis B about 90% of the time. [ 53 ]  For both Hepatitis B and Hepatitis D, the most significant long-term complications are progression to cirrhosis and hepatocellular carcinoma, which carries high morbidity and mortality. [ 54 ]


Neonatal infection treatment is typically started before the diagnosis of the cause can be confirmed.
Neonatal infection can be prophylactically treated with antibiotics. [ 55 ]  Maternal treatment with antibiotics is primarily used to protect against group B streptococcus. [ 30 ]


Women with a history of  genital herpes , can be treated with antiviral drugs to prevent symptomatic lesions and viral shedding that could infect the infant at birth. The antiviral medications used include acyclovir, penciclovir, valacyclovir, and famciclovir. Only very small amounts of the drug can be detected in the fetus. There are no increases in drug-related abnormalities in the infant that could be attributed to acyclovir. Long-term effects of antiviral medications have not been evaluated for their effects after growth and development of the child occurs. Neutropenia can be a complication of acyclovir treatment of neonatal HSV infection, but is usually transient. [ 41 ]  Treatment with immunoglobulin therapy has not been proven to be effective and is not recommended. [ 56 ]


Up to 3.3 million newborns die each year and 23.4% of these die of neonatal infection. About half of the deaths caused by sepsis or pneumonia happen in the first week postpartum. In industrialized countries, prophylactic antibiotic treatment of the mothers identified with group B streptococcus, early identification of sepsis in the newborn, and administration of antibiotics to the newborn has reduced mortality. [ 31 ]  Neonatal herpes in North America is estimated to be from 5 – 80 per 100,000 live births. HSV has a lower prevalence in mothers outside the United States. In the United Kingdom the incidence is much lower and estimated to be 1.6 per 100,000 live births. Approximately 70% to 80% of infected infants are born to mothers with no reported history of HSV infection. [ 41 ]


Regions with low neonatal mortality include Europe, the Western Pacific, and the Americas, which have sepsis rates that account for 9.1% to 15.3% of the total neonatal deaths worldwide. This is in contrast with the 22.5 to 27.2% percentage of total deaths in resource-poor countries such as Nigeria, the Democratic Republic of the Congo, India, Pakistan, and China. [ 31 ]


In the UK, the proportions of pregnant women who are newly screened positive for hepatitis B, syphilis, and HIV have remained constant since 2010 at about 0.4%, 0.14% and 0.15%, respectively. Estimated prevalence levels among pregnant women for hepatitis B and HIV, including previous diagnoses, were higher at 0.67% and 0.27%. Pregnant women evaluated as susceptible to rubella due to low antibody levels have increased by over 60%, to about 7.2%. However, this increase is probably due to changes in testing methods and evaluation criteria. [ 57 ]


In North America, prior to the 1950s, group A β-hemolytic streptococcus (GAS) was the most common pathogen associated with neonatal sepsis prior to the 1960s. In the past twenty years, the most common pathogen causing sepsis is coagulase-negative staphylococci that exist as biofilms associated with infected central venous or arterial catheters. [ 55 ]  Infections can be fatal and contribute to long-term morbidity and disability among the infants who survive into childhood. [ 55 ]  Neonatal sepsis effects 128 cases per 1000 live births. Meningitis can occur in the septic infant. [ 30 ]
Expectant mothers with HSV have a 75% chance of at least one flare-up during their pregnancy. [ 41 ]  In limited studies it was found that infants in Africa born to mothers with malaria have a 7% of acquiring congenital malaria. [ 22 ]


Early onset sepsis can occur in the first week of life. It usually is apparent on the first day after birth. This type of infection is usually acquired before the birth of the infant.  Premature rupture of membranes  and other  obstetrical complications  can add to the risk of early-onset sepsis. If the amniotic membrane has been ruptured greater than 18 hours before delivery the infant may be at more risk for this complication. Prematurity, low birth weight, chorioamnionitis, maternal urinary tract infection and/or maternal fever are complications that increase the risk for early-onset sepsis. Early onset sepsis is indicated by serious respiratory symptoms. The infant usually develops pneumonia, hypothermia, or shock. The mortality rate is 30 to 50%. [ 30 ]


Infections that occur after the first week of life but before the age of 30 days are considered late onset infections. Obstetrical and maternal complications are not typically the cause of these late onset infections; they are usually acquired by the infant in the hospital neonatal intensive care unit. The widespread use of broad-spectrum antibiotics in the nursery intensive care unit can cause a higher prevalence of invasive antibiotic resistant bacteria. [ 30 ]  Meconium aspiration syndrome has a mortality rate just over 4%. This accounts for 2% for all neonatal deaths. [ 58 ]


The susceptibility to risk of infection and immune deficiencies are active areas of research. Studies regarding the role of viruses in neonatal infections are lacking. Research also continues into the role and protective effect of gut, skin and other human microbiomes and the colonization during the neonatal period. [ 26 ] [ 30 ]  The comparison between both resource rich and poor countries makes it difficult to compare the diagnosis success; as industrialized regions are able to confirm the diagnosis and presence of pathogens in the clinical laboratory. Clinical testing may not be available in all settings and clinicians must rely on the signs of infection in the newborn. Research data from Africa and Southeast Asia is scarce. [ 31 ]


The result of some research has been the identification of diagnostic tools and procedures that could identify mothers with group B streptococcus infection in resource-poor regions. These procedures would be easy and inexpensive to use. Those mothers who are identified as being infected could then be prophylactly treated prior to the birth of the baby. [ 31 ]


Probiotic administration of Lactobacillus species has shown some success. [ 59 ]


A GBS vaccine is currently being tested but not currently available. Vaccination is estimated to being able to prevent 4% of GBS infections for preterm births and 60–70% for neonatal GBS infections in the US. The projected benefits of maternal vaccination is the prevention of 899 cases of GBS disease and 35 deaths among infants. The cost savings in the prevention of GBS may be over 43 million dollars. Vaccination may be especially beneficial in low to middle income countries where screening and prophylactic treatment is not possible. Analysts project that GBS vaccination would prevent 30–54% of infant GBS cases. Screening, prophylactic antibiotics and vaccine would prevent 48% of infection. [ 60 ]


Neurosyphilis  is the infection of the  central nervous system  in a patient with  syphilis . In the era of modern  antibiotics , the majority of neurosyphilis cases have been reported in  HIV-infected  patients. [ citation needed ]   Meningitis  is the most common neurological presentation in early syphilis.  Tertiary syphilis  symptoms are exclusively neurosyphilis, though neurosyphilis may occur at any stage of infection.


To diagnose neurosyphilis, patients undergo a  lumbar puncture  to obtain  cerebrospinal fluid  (CSF) for analysis. The CSF is tested for  antibodies  for specific  Treponema pallidum   antigens . The preferred test is the  VDRL test , which is sometimes supplemented by  fluorescent treponemal antibody absorption test  (FTA-ABS). [ 1 ] [ 2 ] [ 3 ]


Historically, the disease was studied under the  Tuskegee study , often cited as an example of  unethical human experimentation . The study was done on approximately 400  African-American  men with untreated syphilis who were followed from 1932 to 1972 and compared to approximately 200 men without syphilis. The study began without  informed consent  of the subjects and was continued by the  United States Public Health Service  until 1972. The researchers failed to notify and withheld treatment for patients despite knowing  penicillin  was found as an effective cure for neurosyphilis. After four years of follow-up, neurosyphilis was identified in 26.1% of patients vs. 2.5% of controls. After 20 years of followup, 14% showed signs of neurosyphilis and 40% had died from other causes.


The signs and symptoms of neurosyphilis vary with the disease stage of  syphilis . The stages of syphilis are categorized as primary, secondary, latent, and tertiary. It is important to note that neurosyphilis may occur at any stage of infection. [ citation needed ]


Meningitis  is the most-common neurological presentation in early syphilis. It typically occurs in the secondary stage, arising within one year of initial infection. The symptoms are similar to other forms of meningitis. The most common associated with  neurosyphilitic meningitis  is  cranial nerve   palsy , especially of the  facial nerve . [ 4 ] [ 5 ]


Nearly any part of the eye may be involved. The most common form of ocular syphilis is  uveitis . Other forms include  episcleritis ,  vitritis ,  retinitis ,  papillitis ,  retinal detachment , and  interstitial keratitis . [ 2 ] [ 6 ]


Meningovascular syphilis  usually occurs in late syphilis but may affect those with early disease. It is due to  inflammation  of the vasculature supplying the  central nervous system , that results in  ischemia . It typically occurs about 6–7 years after initial infection and it may affect those with early disease. It may present as  stroke  or spinal cord infarct. Signs and symptoms vary with vascular territory involved. The  middle cerebral artery  is most often affected. [ 7 ]


Parenchymal syphilis occurs years to decades after initial infection. It presents with the constellation of symptoms known as  tabes dorsalis , because of a degenerative process of the  posterior columns of the spinal cord . The constellation includes  Argyll Robertson pupil , ataxic wide-based gait,  paresthesias , bowel or bladder  incontinence , loss of position and vibratory sense, loss of deep pain and temperature sensation, acute episodic gastrointestinal pain,  Charcot joints , and general paresis.


Gummatous  disease may also present with destructive inflammation and space-occupying lesions. It is caused by  granulomatous  destruction of  visceral  organs. They most often involve the  frontal  and  parietal lobes  of the brain. [ citation needed ]


Although neurosyphilis is a neurological disease, neuropsychiatric symptoms might appear due to overall damage to the brain. These symptoms can make the diagnosis more difficult and can include symptoms of  dementia , [ 8 ] [ 9 ]   mania ,  psychosis ,  depression , [ 10 ]  and  delirium : [ 11 ]


These symptoms are not always present, and when they are, they usually appear in more advanced stages of the disease. [ 12 ]


The  Jarisch-Herxheimer reaction  is an immune-mediated response to syphilis therapy occurring within 2-24 hours. The exact mechanisms of reaction are unclear, however most likely caused by proinflammatory treponemal  lipoproteins  that are released from dead and dying organisms following antibiotic treatment. It is typically characterized by fever, headache,  myalgia , and possibly intensification of skin rash. It most often occurs in early-stage syphilis (up to 50%-75% of patients with primary and secondary syphilis). It is usually self-limiting and managed with  antipyretics  and  nonsteroidal anti-inflammatory medications .


There are several risk-factors: High-risk sexual behavior from unprotected sex and multiple sexual partners. [ citation needed ]  The HIV infection  antiretroviral therapy  (ART) suppresses HIV transmission, but not syphilis transmission. It may also be associated with recreational drug use. [ citation needed ]


The pathogenesis is not fully known, in part due to fact that the organism is not easily  cultured . Within days to weeks after initial infection,  Treponema pallidum  disseminates via blood and  lymphatics . The organism may accumulate in perivascular spaces of nearly any organ, including the central nervous system (CNS). It is unclear why some patients develop CNS infection and others do not. Rarely, organisms may invade any structures of the eye (such as  cornea ,  anterior chamber ,  vitreous  and  choroid , and  optic nerve ) and cause local inflammation and edema. In primary or secondary syphilis, invasion of the meninges may result in  lymphocytic  and  plasma cell  infiltration of  perivascular spaces  (Virchow–Robin spaces). The extension of cellular immune response to the  brainstem  and  spinal cord  causes inflammation and necrosis of small meningeal vessels. [ citation needed ]


In tertiary syphilis, reactivation of chronic latent infection may result in meningovascular syphilis, arising from  endarteritis obliterans  of small, medium, or large arteries supplying the CNS. The parenchymal syphilis, presents as  tabes dorsalis  and general paresis. Tabes dorsalis thought to be due to irreversible degeneration of nerve fibers in  posterior columns of the spinal cord  involving the  lumbosacral  and lower  thoracic  levels. The general paresis is caused by meningeal vascular inflammation and  ependymal   granulomatous  infiltration may lead to neuronal loss, along with  astrocytic  and  microglial  proliferation and damage may preferentially occur in the  cerebral cortex ,  striatum ,  hypothalamus , and  meninges . [ citation needed ]


Concurrent infection of  T. pallidum  with  human immunodeficiency virus  (HIV) has been found to affect the course of syphilis. Syphilis can lie dormant for 10 to 20 years before progressing to neurosyphilis, but HIV may accelerate the rate of the progress. Also, infection with HIV has been found to cause penicillin therapy to fail more often. Therefore, neurosyphilis has once again been prevalent in societies with high HIV rates [ 2 ]  and limited access to penicillin. [ 13 ]


To diagnose neurosyphilis,  cerebrospinal fluid  (CSF) analysis is required.  Lumbar puncture  ("spinal tap") is used to acquire CSF. The  Venereal Disease Research Laboratory test  of the CSF is the preferred test for making a diagnosis of neurosyphilis. [ 14 ]  A positive test confirms neurosyphilis but a negative result does not rule out neurosyphilis. Due to the low sensitivity of the CSF VDRL,  fluorescent treponemal antibody absorption test  (FTA-ABS) can be used to supplement VDRL. Reported sensitivity is variable. [ 1 ]   False-negative  antibody test result occurring when antibody concentration is so high that  agglutination  reaction cannot occur, which is typically seen during secondary stage and can be overcome by diluting test sample 1:10. CSF  white blood cell  count is often elevated in the early stages of neurosyphilis, ranging from about 50 to 100 white blood cells/mcL with a  lymphocyte  predominance. Cell counts are typically lower in late syphilis. Regardless of syphilis disease stage, the absence of CSF white blood cells rules out neurosyphilis. [ citation needed ]


Penicillin  is used to treat neurosyphilis. [ 2 ]  Two examples of penicillin therapies include: [ 1 ]


Follow-up blood tests are generally performed at 3, 6, 12, 24, and 36 months to make sure the infection is gone. [ 1 ]  Lumbar punctures for CSF fluid analysis are generally performed every 6 months until cell counts normalize. All patients with syphilis should be tested for HIV infection. [ 15 ]  All cases of syphilis should be reported to public health authorities and public health departments can aid in partner notification, testing, and determining need for treatment. [ 16 ]


The treatment success is measured with a fourfold drop in the nontreponemal antibody test. In early-stage syphilis drop should occur in 6–12 months; in late syphilis drop can take 12–24 months. Titers may decline more slowly in persons who have previously had syphilis. [ citation needed ]


In people who cannot take penicillin doxycyclin can be used for treating neurosyphilis. [ 17 ]


A  nontreponemal test  ( NTT ) is a  blood test  for diagnosis of infection with  syphilis . Nontreponemal tests are an indirect method in that they detect  biomarkers  that are released during cellular damage that occurs from the syphilis  spirochete . In contrast, treponemal tests look for  antibodies  that are a direct result of the infection thus, anti-treponeme IgG, IgM and to a lesser degree IgA. Nontreponemal tests are screening tests, very rapid and relatively simple, but need to be confirmed by treponemal tests. [ 1 ]  Centers for Disease Control and Prevention (CDC)-approved standard tests include the  VDRL test  (a slide test), the  rapid plasma reagin  (RPR) test (a card test), the unheated serum reagin (USR) test, and the  toluidine red  unheated serum test (TRUST). [ 2 ]  These have mostly replaced the first nontreponemal test, the  Wassermann test . [ citation needed ]


Syphilitic infection leads to the production of nonspecific antibodies that react to  cardiolipin . This reaction is the foundation of “nontreponemal” assays such as the VDRL ( Venereal Disease Research Laboratory ) test and  Rapid Plasma Reagin  (RPR) test. Both these test are  flocculation  type tests that use an  antigen-antibody interaction . The complexes remain suspended in solution and therefore visible due to the  lipid  based  antigens . [ 3 ] [ 4 ]


All nontreponemal tests measure  immunoglobulins  G (IgG) and M (IgM) anti-lipid antibodies formed by the host in response both to lipoidal material released from damaged host cells early in infection and to lipid from the cell surfaces of the treponeme itself. [ citation needed ]


These nontreponemal tests are widely used for qualitative syphilis screening. However, their usefulness is limited by decreased sensitivity in early primary syphilis and during late syphilis, when a large number of untreated patients will be negative by these methods. [ citation needed ]


With nontreponemal tests, false-positive reactions can occur for a large number of reasons, the most common of which is other infections, both viral and bacterial. Additionally these tests may show false-negative when the patient's antibody titer is very high due to a  hook effect  (also called a prozone effect). Because of the issues with false positives, confirmation with a second treponemal test that is specific for  T. pallidum  antibodies is recommended. [ 5 ] [ 6 ]


The tests are relatively simple to perform and interpret, and can allow rapid return of results and are very cheap. However, they still require some laboratory equipment (especially the VDRL) and trained personnel to perform and interpret test reactions. [ 2 ]


Partner notification  is the practice of notifying the  sexual partners  of a person, known as the "index case", who has been newly diagnosed with a  sexually transmitted infection  that they may have been exposed to the infection. It is a kind of  contact tracing  and is considered a  partner service .


In the UK, partner notification has not played a significant part in HIV prevention and testing efforts despite proving to be highly effective in diagnosing people with HIV. Some audits show up to 37% of partners traced and tested through partner notification were newly diagnosed HIV positive as a result. [ 1 ]  Notifying sexual partners of people diagnosed with HIV is usually voluntary but a healthcare worker may decide to contact partners without consent if they feel there is a risk of HIV transmission. [ 2 ]  This is permitted under General Medical Council guidance. [ 3 ]


A 2002 survey in the United States showed that with regards to STIs, healthcare providers conduct screenings with less frequency than recommended by health department guidelines.  Furthermore, when a person was found to have a sexually transmitted infection, it was much more common for the physician to ask the person to notify their partners rather than for the physician to arrange for this to be done on behalf of the patient. [ 4 ]


A study in  San Francisco  conducted between 2004 and 2006 showed that many new diagnoses of HIV infection were made as a result of one person getting HIV tested, and then contacting that person's partner if the test was positive.  It was sometimes the case that a positive person also had a positive partner.  Patients rarely refused partner services, and their partners rarely refused to present themselves for healthcare when asked by the clinic. [ 5 ]


In the past, the CDC has recommended that physicians and health departments should inform the sexual partners of people known to be infected with HIV of their risk for contracting the disease when the diagnosed individual refused to do so. [ 6 ]  However, the CDC currently recommends that all partner services, including partner notification, should be "voluntary and non-coercive" for both the individual initially diagnosed with the STD and their sexual partners. [ 7 ]  Despite the change, as of 1998, several states in the US have laws that codify involuntary or coercive partner notification. [ 8 ]   In Michigan and Indiana, individuals who test positive for HIV are legally obligated to notify past sexual contacts. [ 8 ]  In Texas and other states, doctors and public health officials are either required or authorized to inform known sexual contacts of patients who have tested positive for HIV. [ 8 ]


In  New South Wales ,  Australia , if a health worker believes that the behavior of the index case poses a risk to the health of the public, then the worker is obligated to inform the Director-General of NSW health, who has the sole authority to inform partners of the index case without their consent. [ 9 ]


Patient-delivered (partner) therapy  (PDT or PDPT), is the practice of treating the sex partners of people diagnosed with  chlamydia  or  gonorrhea  by providing prescriptions or medications to the person to take to their partner without the health care provider first examining the partner. [ 2 ]  EPT may also include other forms of implementation than PDPT. [ 2 ]


PDPT works as an addition to the usual  patient referral , the latter being that the  index patient  has a responsibility for informing sex partners of their exposure to a sexually transmitted infection. [ 3 ]  PDPT significantly reduces the risk of persistent or recurrent infection compared with patient referral alone; a review found that addition of PDPT gives a  relative risk  of 0.73, with a 95%  confidence interval  of 0.57 to 0.93. [ 3 ]


Pitfalls include that PDT may compromise the quality of care provided to partners, especially when used as a first-line approach for partners who would otherwise seek clinical services. For instance, the medication could cause serious adverse reactions, including allergy, which could have been foreseen by a visit to a health care provider. [ 4 ]


Pediculosis pubis  (also known as " crabs " and " pubic lice ") is an  infestation  by the  pubic louse ,  Pthirus pubis , a wingless  insect  which feeds on blood and lays its eggs (nits) on mainly  pubic hair . Less commonly, hair near the anus, armpit, beard, eyebrows, moustache, and eyelashes may be involved. [ 1 ] [ 2 ] [ 3 ]  It is usually acquired during  sex , but can be spread via bedding, clothing and towels, and is more common in crowded conditions where there is close contact between people. [ 1 ] [ 4 ]


The main symptom is an intense  itch  in the groin, particularly at night. There may be some grey-blue discolouration at the feeding site, and eggs and lice may be visible. [ 1 ] [ 2 ] [ 3 ]  Scratch marks, crusting and scarring may be seen, and there may be signs of secondary bacterial infection. [ 1 ]


Diagnosis is by visualising the nits or live lice, either directly or with a magnifying glass. [ 5 ]  Investigations for other  sexually transmitted infections  (STIs) are usually performed. [ 6 ]


First line treatment usually contains  permethrin  and is available over the counter. [ 3 ]  Two rounds of treatment at least a week apart are usually required to kill newly hatched nymphs. [ 5 ]  Washing bedding and clothing in hot water kills the lice, and transmission can be prevented by avoiding sexual contact until no signs of infestation exist. Eggs may be removed by combing pubic hair with a comb dipped in vinegar. [ 6 ]  Sexual partners should be evaluated and treated. [ 6 ]


Infestation with pubic lice is found in all parts of the world and occurs in all ethnic groups and all levels of society. [ 6 ]  Worldwide, the condition affects about 2% of the population. [ 7 ]


The onset of symptoms is typically three weeks after the first infestation of lice and is mainly an intense  itch  in the pubic area and groin, particularly at night, resulting from an allergic reaction to the saliva of feeding lice. [ 1 ] [ 4 ] [ 8 ]  In some infestations, a characteristic grey-blue or slate coloration  macule  appears ( maculae caeruleae ) at the feeding site, which may last for days. Nits or live lice may be seen crawling on the skin. [ 3 ] [ 9 ] [ 6 ]  Louse droppings may be noticed as a black powder in the underwear. [ 8 ]


Scratch marks, crusting, scarring, rust-colored faecal material, blood stained underwear and secondary bacterial infection may sometimes be seen.  Large lymph nodes  in the groin and armpits may be felt. [ 1 ]  Some people with pubic lice infestation may not have any symptoms. [ 9 ]


Complications are usually as a result of persistent scratching and include  thickening of the skin ,  darkened skin , and secondary bacterial infection including  impetigo ,  conjunctivitis  and  blepharitis . [ 1 ] [ 8 ]


Pubic lice are usually transmitted from one person to another during  vaginal ,  oral ,  anal  or  manual sex , whether a  condom  is used or not. [ 4 ] [ 8 ] [ 10 ]  One sexual encounter with an infected person carries a high risk of catching pubic lice. [ 11 ]  In some circumstances transmission can occur through kissing and hugging, and less likely via bedding, clothing and towels. The lice spread more easily in crowded conditions where the distance between people is close, allowing the lice to crawl from one person to another. [ 1 ] [ 8 ]


Infestation on the eyebrows or eyelashes of a child may indicate sexual exposure or abuse. [ 6 ]


Pubic lice ( Pthirus pubis ) have three stages: the egg (also called a nit), the nymph, and the adult. They can be hard to see and are found firmly attached to the hair shaft. They are oval and usually yellow to white. Pubic lice nits take about 6–10 days to hatch. The nymph is an immature louse that hatches from the nit (egg). A nymph looks like an adult pubic louse but it is smaller. Pubic lice nymphs take about 2–3 weeks after hatching to mature into adults capable of reproducing. To live, a nymph must feed on blood. The adult pubic louse resembles a miniature crab when viewed through a strong magnifying glass. Pubic lice have six legs; their two front legs are very large and look like the pincher claws of a crab—thus the nickname "crabs". Pubic lice are tan to grayish-white in color. Females lay nits and are usually larger than males. [ 6 ]  To live, lice must feed on blood. If the louse falls off a person, it dies within 1–2 days. Eggs (nits) are laid on a hair shaft. Females will lay approximately 30 eggs during their 3–4 week life span. Eggs hatch after about a week and become nymphs, which look like smaller versions of the adults. The nymphs undergo three molts before becoming adults. Adults are 1.5–2.0 mm long and flattened. They are much broader in comparison to head and body lice. Adults are found only on the human host and require human blood to survive. Pubic lice are transmitted from person to person most-commonly via sexual contact, although fomites (bedding, clothing) may play a minor role in their transmission. [ 4 ] [ 12 ]


Diagnosis is made by carefully looking at the pubic hair for  nits ,  young lice  and adult lice. [ 4 ]  Lice and nits can be removed either with forceps or by cutting the infested hair with scissors (with the exception of an infestation of the eye area). [ 5 ]  A magnifying glass,  dermatoscope  or a  stereo-microscope  can be used for identification. [ 2 ] [ 5 ]  Testing for other  sexually transmitted infections  is recommended in those who are infested with pubic lice. [ 4 ]


Pediculosis pubis is an  infestation  by the  pubic louse ,  Pthirus pubis , a wingless  insect  which feeds on blood and lays its eggs (nits) on mainly  pubic hair . Less commonly, hair near the anus, armpit, beard, eyebrows, moustache, and eyelashes may be involved. [ 1 ] [ 2 ] [ 3 ]  Although the presence of pubic lice is associated with the presence of other sexually transmitted diseases, pubic lice do not spread infectious diseases. [ 13 ]


Pubic lice can be treated at home. Available treatments may vary from country to country and include mainly  permethrin -containing creams and lotions applied to cool dry skin or applying  dimethicone -based oils. [ 2 ]


Treatment with medication is combined with combing pubic hair with a fine-toothed comb after applying vinegar directly to skin or dipping the comb in vinegar, to remove nits. [ 1 ] [ 3 ]  It is recommended to wash bedding, clothing and towels in hot water or preferably in a washing machine at 50°C or higher. When this is not possible, the clothing can be stored in a sealed plastic bag for at least three days. [ 2 ] [ 14 ]  Re-infestation can be prevented by wearing clean underwear at the start of treatment and after completing treatment. [ 2 ]  Shaving the affected hair is not essential. [ 2 ]


At first, treatment is usually with topical permethrin 1% cream, which can be bought over the counter without a prescription. It is applied to the areas affected by pubic lice and washed off after 10 minutes. [ 6 ]  Brands of permethrin include 'Lyclear', available in the UK as a creme rinse or dermal cream at 5% strengths. [ 15 ] [ 16 ]
In the US, common permethrin brands include NIX, Actin and Elimite. [ 17 ]


An alternative is the combination of  pyrethrins  and  piperonyl butoxide , in a topical application, which include the brands Licide, and A-200, Pronto and RID shampoos. [ 14 ] [ 18 ]  These medications are safe and effective when used exactly according to the instructions in the package or on the label. [ 6 ]  To kill newly hatched lice, both treatments can be repeated within the following seven to ten days. [ 5 ] [ 19 ]


European guidelines state alternatives to permethrin as including either the application of 0.2%  phenothrin  (washed off after two hours), or 0.5%  malathion  lotions (washed off after 12 hours). [ 2 ]  The CDC states alternatives as topical 0.5% malathion or oral  ivermectin . [ 14 ]


Lindane  is still used in a shampoo form in some non-European countries. Its licence was withdrawn by the European Medicines Agency in 2008. [ 2 ]  It may be considered as a last resort in some people who show resistance to other treatments, but is not recommended to be used for a second round of treatment. [ 2 ] [ 4 ]  Lindane is not recommended in pregnant and breastfeeding women, children under the age of two years, and people who have extensive  dermatitis . [ 4 ] [ 6 ]  The FDA warns against use in people with a history of uncontrolled  seizure disorders  and cautious use in infants, children, the elderly, and individuals with other skin conditions (e.g.,  atopic dermatitis ,  psoriasis ) and in those who weigh less than 110 lbs (50 kg). [ 6 ] [ 20 ]   Carbaryl  has been used since 1976 but found to have the potential to  cause cancer  in  rodents  and not to be as effective as previously thought. It is either not used at all or its use is restricted. [ 2 ] [ 21 ]


Sexual partners should be evaluated and treated, and sexual contact should be avoided until all partners are better. Because of the strong association between the presence of pubic lice and sexually transmitted infections (STIs), affected people require investigation for other STIs. [ 6 ]


Infestation of the eyes is treated differently from other parts of the body. Lice can be removed with forceps or by removing or trimming the lashes. [ 22 ]  Eyelashes may be treated with a gentle  petroleum jelly  for occlusion. [ 22 ]


Infestation with pubic lice is found in all parts of the world, occurs in all ethnic groups and all levels of society. [ 6 ]


Current worldwide prevalence has been very approximately estimated at two percent of the human population. Accurate numbers are difficult to acquire, because  pubic lice  infestations are not considered a reportable condition by many governments. Many cases are self-treated or treated discreetly by personal physicians, which further adds to the difficulty of producing accurate statistics. [ 7 ]


It has been reported that the trend of pubic hair removal has led to the destruction of the natural habitat of the crab louse populations in some parts of the world, thereby reducing the incidence of the disease. [ 2 ] [ 23 ] [ 24 ]


Infestation with pubic lice is also called  phthiriasis  or  phthiriasis pubis , while infestation of eyelashes with pubic lice is called  phthiriasis palpebrarum  or  pediculosis ciliarum . [ 25 ]  Linnaeus was first to describe and name the pubic louse in 1758, when he called it Pediculus pubis. The disease is spelled with  phth , but the scientific name of the louse  Pthirus pubis  is spelled with  pth  (an etymologically incorrect spelling that was nonetheless officially adopted in 1958). [ 26 ]


Humans  are the only known hosts of this parasite, [ 3 ]  although a closely related species,  Pthirus gorillae , infects  gorilla  populations. [ 27 ]


"Pediculis [ sic ] Pubis" is a crude song by the  Yugoslav rock  band  Bijelo Dugme  recorded in 1984 as part of their self-titled album  Bijelo Dugme . [ 28 ]


Penile discharge  is fluid that comes from the  urethra  at the end of the  penis  that is not  urine ,  pre-ejaculate  or  semen . [ 2 ] [ 3 ]


Common causes include infections due to  gonorrhea ,  chlamydia , or  trichomoniasis . [ 3 ]  In gonorrhea the discharge may be white, yellow, or green. [ 4 ] [ 5 ]


A swab of the discharge is usually performed. [ 5 ]


Treatment depends on the cause. Spread of infection is reduced by also  treating sexual contacts . [ 6 ]


Risk factors include being sexually active men under the age of 25, having a recent new sexual partner, or having unprotected sex. [ 6 ]


Penile discharge is liquid from the  urethra  at the end of the penis that is not urine or semen. [ 2 ]  The dripping of clear fluid ( pre-ejaculate ) when sexually excited is normal. [ 2 ]


There may be pain or burning when passing urine, soreness inside the penis or feeling of wanting to pass urine frequently. [ 6 ]


Common causes include infections due to  gonorrhea ,  chlamydia , or  trichomoniasis . [ 3 ]


Other causes include:


A swab of the discharge is usually performed. [ 5 ]  Other investigations may include tests for HIV, hepatitis and syphilis. [ 6 ]


Men who have sex with men may also need to have throat and rectal swabs. [ 6 ]


Treatment depends on the cause and any antibiotic prescribed depends on which infection is found. [ 6 ]  Spread of infection is reduced by  informing sexual partners  so that they can also be treated, and not having sex (including oral or anal) until tests are completed and seven days have passed after treatment. [ 6 ]


Risk factors include being sexually active men under the age of 25, having a recent new sexual partner, unprotected sex (without a condom), or having the presence of any sexually transmitted infection. [ 6 ]


Prevotella bivia  is a species of  bacteria  in the  genus   Prevotella .  It is  gram-negative .  It is one cause of  pelvic inflammatory disease . [ 1 ]


Other  Prevotella  spp. are members of the  oral and  vaginal microbiota , and are recovered from  anaerobic infections  of the respiratory tract. These infections include  aspiration pneumonia , lung  abscess , pulmonary empyema, and chronic  otitis media  and  sinusitis . Other species have been isolated from abscesses and burns in the vicinity of the mouth,  bites ,  paronychia ,  urinary tract infection ,  brain abscesses ,  osteomyelitis , and  bacteremia  associated with  upper respiratory tract infections .  Prevotella  spp. predominate in  periodontal disease  and periodontal abscesses. [ 2 ]   The genus also includes gut bacteria. [ 3 ]   Prevotella  species dominate with high fiber, plant-based diets. [ 4 ]


Human  Prevotella  spp have been compared genetically with species derived from different body sites of humans. [ 5 ]


Protein M  (locus MG281) is an immunoglobulin-binding protein originally found on the cell surface of the  human pathogenic bacterium   Mycoplasma genitalium . It is presumably a universal antibody-binding protein, as it is known to be reactive against all antibody types tested so far. It is capable of preventing the  antigen-antibody interaction  due to its high  binding affinity  to any antibody.  The Scripps Research Institute  announced its discovery in 2014. [ 1 ]  It was detected from the bacterium while investigating its role in patients with a cancer,  multiple myeloma . [ 2 ] [ 3 ]


Homologous proteins are found in other  Mycoplasma  bacteria. [ 2 ]   Mycoplasma pneumoniae , another human pathogen, has a homolog termed IbpM (locus MPN400). [ 4 ]


Mycoplasma genitalium  was discovered in 1980 from two male patients with  non-gonococcal urethritis  at  St Mary's Hospital, Paddington, London . [ 5 ]  After two years, in 1983, it was identified as a new species. [ 6 ]  After several years of intense research, it was found to be the cause of sexually transmitted diseases, such as  urethritis  (inflammation of the urinary tract) both in men and women, and also  cervicitis  (inflammation of cervix) and  pelvic inflammation  in women. [ 7 ] [ 8 ]  However, the molecular nature of its pathogenicity remained unknown for three decades. [ citation needed ]


On 6 February 2014, The Scripps Research Institute announced the discovery of a novel protein, which they named Protein M, from the  M. genitalium  cell membrane. [ 1 ]  Scientists identified the protein during investigations on the origin of  multiple myeloma , a type of B-cell carcinoma. To understand the long-term  M. genitalium  infection, Rajesh Grover, a senior staff scientist in the Lerner laboratory, tested antibodies from the blood samples of patients with multiple myeloma against different  Mycoplasma  species. He found that  M. genitalium  was particularly responsive to all types of  antibodies  he tested from 20 patients. [ 9 ]  The antibody reactivity was found to be due to an undiscovered protein that is chemically responsive to all types of human and non-human antibodies available. [ 10 ]  When they isolated and analysed the protein, they discovered that it was unique both in structure and biological functions. Its structure has no resemblance to any known protein listed in the Protein Data Bank. [ 2 ]


Protein M is about 50  kDa  in size, and composed of 556 amino acids. Contrary to the initial hypothesis that the antibody reactions could be an immune response to mass infection with the bacterium, they found that Protein M evolved simply to bind to any antibody it encounters, with specifically high affinity. By this property the bacterium can effectively evade the  immune system  of the host. This makes the protein an ideal target for developing new drugs. [ 11 ] [ 12 ]  Rajesh Grover estimated that the protein can bind to an average of 100,000,000 different kinds of antibodies circulating in human blood. [ 13 ]


Unlike functionally similar proteins such as  Protein A ,  Protein G , and  Protein L , which all contain small, multiple immunoglobulin domains, Protein M has a large domain of 360 amino acid residues that binds primarily to the variable light chain of the immunoglobulin, as well as a binding site called LRR-like motif. In addition, Protein M has a C-terminal domain with 115 amino acid residues that probably protrudes over the antibody binding site. It binds to an antibody at either κ or λ light chains using  hydrogen bonds  and  salt bridges , from backbone atoms and conserved side chains, and some conserved  van der Waals interactions  with other nonconserved interactions. [ 2 ]


A  rectal microbicide  is a  microbicide  for  rectal  use.  Most commonly such a product would be a  topical  gel inserted into the  anus  so that it make act as protection against the contract of a  sexually transmitted infection  during  anal sex . [ citation needed ]


Along with  vaginal microbicides , rectal microbicides are currently the subject of medical research on  microbicides for sexually transmitted diseases  to determine the circumstances under which and the extent to which they provide protection against infection.


Less commonly, rectal microbicides can have other purposes also; for example, they could be used to treat certain medical conditions as a  suppository  would.


Early development of topical microbicides starting around 1998 focused on preventing of HIV transmission during vaginal intercourse. [ 1 ]   The entire field lacks a  proof of concept  that a vaginal microbicide exists. [ 1 ]   As of 2008, 16 topical microbicides entered phase I or II  clinical trial  and 7 advanced to an additional trial. [ 1 ]  Previous studies both showed promise in new areas of research and gave disappointing results from the first generation products, as surfactants like  nonoxynol-9  and entry inhibitors like  carrageenan  showed no efficacy in preventing HIV and were associated with risk of inflammation which raised the risk of contracting HIV in some circumstances. [ 1 ]


In 1998, researchers noted that gay men using products containing nonoxynol-9 as part of their infection prevention strategy despite lack of evidence of efficacy or any safety data for that practice. [ 2 ]  At the time, the drug was under evaluation as a vaginal microbicide. [ 2 ]


Because of expected similarities between the efficacy of vaginal and rectal microbicides, some researchers have called for all vaginal microbicides to be tested for efficacy when used rectally. [ 3 ]


There are two fundamental reasons to research and develop rectal microbicides for HIV prevention:


Concerted advocacy for the research and development of safe, effective, acceptable and accessible rectal microbicides began in 2005, when  International Rectal Microbicide Advocates  was founded with colleagues representing the  AIDS Foundation of Chicago , the  Canadian AIDS Society , the  Community HIV/AIDS Mobilization Program , and the  Global Campaign for Microbicides . [ citation needed ]


The political and sociocultural context reinforced the dismissal of rectal microbicides. Pervasive homophobia across the globe has resulted in a lack of adequate attention and resources devoted to gay men and other men who have sex with men (MSM) despite the disproportional HIV burden borne by this population. [ 7 ]  Few knew, or acknowledged, that anal intercourse is a widespread practice among heterosexuals, both men and women, gay men and other MSM, as well as transgender people. Thus, evidence-free assumptions relegated the rectal portion of the microbicide field to a small, dark corner. [ citation needed ]


The field has moved from simply being an adjunct to vaginal studies to a force in its own right. This is due to a handful of visionary, passionate, and dogged scientists; funding from the United States (which has supported approximately 97% of all rectal microbicide research); and growing community engagement. [ 8 ]


Preclinical testing for rectal microbicides has been conducted in  macaques  to get a nonhuman primate model of drug behavior. [ 9 ]


Scientists working on the University of California, Los Angeles (UCLA's) Microbicide Development Program initiated the first Phase I RM safety trial, investing the safety and acceptability of UC-781, in December 2006. Rectal application of UC-781 gel, a potent antiretroviral (ARV) drug, was shown to be safe and acceptable to the 36 men and women in the trial. Phase I trials normally focus solely on safety and acceptability, but researchers used a novel approach in this trial: taking rectal tissue biopsies from participants and exposing them to HIV ex vivo in the laboratory. The drug significantly reduced HIV transmission in these essays. [ 10 ]


RMP-02/MTN-006 Tested the same vaginal formulation of tenofovir gel that reduced HIV acquisition by an estimated 39 percent overall in the CAPRISA (Centre for the AIDS Programme of Research) 004 trial that was conducted in South Africa. [ 11 ]  In September 2009, 18 men and women began enrolling in the trial, which was sponsored by the Microbicide Trials Network (MTN) and UCLA's Microbicide Development Program. The study tested the safety and acceptability of single- and multiple-day rectal applications of tenofovir, a single oral dose of tenofovir, and a placebo. [ citation needed ]


Laboratory tests showed that HIV was significantly inhibited in rectal tissue samples from participants who applied tenofovir gel to their rectums daily for one week compared to tissue from those who used a placebo gel. Although a slight anti-HIV effect was noted in tissue from participants who applied a single dose of tenofovir gel, the finding was not statistically significant. The single dose of oral tenofovir did not provide any protection against HIV in rectal tissue samples. The study also discovered that only 25 percent of the participants liked tenofovir gel, compared to 50 percent who had used the placebo gel. Some individuals who used tenofovir gel experienced gastrointestinal distress, cramps, and diarrhea. Results were presented at the 18th Conference on Retroviruses and Opportunistic Infections, or CROI. [ 12 ]


MTN-007 studied a reformulated version of the tenofovir gel. Researchers retained the same concentration of tenofovir (one percent), but reduced the glycerin in the gel in an attempt to make it more acceptable and “rectal friendly.” This Phase I safety and acceptability study, launched in October 2011, included 65 men and women from three sites in the United States. Results were presented at the 19th CROI in March 2012. [ 13 ]  This reduced glycerin formulation of 1 percent tenofovir gel was found to be safe and acceptable. Researchers recommended advancing this candidate to Phase II. [ citation needed ]


MTN-017, the follow-up to MTN-007, represented a major milestone: the first Phase II expanded safety and acceptability study of an RM. The trial was officially launched in October 2013 [ 14 ]  at sites in the United States, Peru, Thailand, and South Africa. The 195 gay men, other MSM, and transgender women recruited into MTN-017 more than doubled the total number of human beings who have participated in RM clinical trials to date, and the trial was also the first to include participants from countries outside of the United States. [ citation needed ]


The study investigated the safety and acceptability of the reduced glycerin tenofovir gel and directly compared acceptability and adherence to daily oral  Truvada . MTN-017 featured an open-label, crossover design in which each individual followed three different regimens, each lasting eight weeks. One regimen consisted of the participant applying the gel to the rectum daily. A second regimen asked participants to apply the gel rectally before and after anal intercourse. In the third regimen, participants took oral Truvada every day. The order in which participants followed the study regimens was assigned randomly, with a break between each regimen. [ citation needed ]


The procedures carried out as part of MTN-017 determined how much of each drug is absorbed in blood, rectal fluid, and tissue, and also assessed any changes in cells or tissue. Study participants were asked about any side effects, what they liked and disliked about using the gel either daily or with sex, and whether they would consider using the gel in the future. Gel acceptability and adherence were directly compared to oral Truvada, which has been shown to reduce the risk of HIV acquisition in a number of studies among different populations. [ 15 ] [ 16 ]


Rectal microbicides can reduce the risk of transmission of HIV during anal intercourse, particularly during sex when condoms are not used. [ 1 ] Researchers have explored using personal lubricant as a vehicle for delivering a rectal microbicide. [ 17 ]


Research into rectal microbicides and funding for exploring their use as public health tools has faced barriers historically because of the  taboo  in discussing anal health and anal sex. [ 18 ]    Researchers have reported feeling disinclined to request funding for "anal research" because of biases against anything to do with an anus, and public policy writers have at times faced opposition to promoting discussion on anal topics. [ 18 ]


Scientists at the Population Council are trying to develop a microbicide that would be both safe and effective in either the vagina or the rectum. They have conducted early work on a combination product containing MIV-150 (an investigational ARV), zinc acetate, and carrageenan gel. Further evaluation of this combination is dependent on funding. [ 19 ]


A  serodiscordant  relationship, also known as  mixed-status , is one where one partner is infected by  HIV  and the other is not. [ 1 ]  This contrasts with  seroconcordant  relationships, in which both partners are of the same HIV status. Without effective prevention measures, serodiscordant relationships can significantly contribute to the spread of  HIV/AIDS , with the risk varying based on the type and frequency of sexual activity and the viral load of the HIV-positive partner. [ 2 ]


Globally, an estimated 34 million people are living with HIV, with 68% residing in  sub-Saharan Africa  nations such as  Lesotho [ 3 ]  and 50% of cases affecting women. In the United States, over 140,000 HIV-serodiscordant heterosexual couples are estimated, with 52% of HIV-positive women in a national study reporting serodiscordant partnerships. Similarly, in sub-Saharan Africa, 47% of HIV-positive women are in stable serodiscordant relationships. [ 4 ]  The  World Health Organization  reports that up to 50% of individuals living with HIV in ongoing relationships worldwide have partners who are HIV-negative. [ 5 ]


Serodiscordant couples face numerous issues not faced by seroconcordant couples, including decisions as to what level of  sexual activity  is comfortable for them, knowing that practicing  safer sex  reduces but does not eliminate the risk of transmission to the HIV-negative partner. There are also potential psychological issues arising out of taking care of a sick partner, and  survivor guilt [ 6 ] . Psychological impacts included anger, fear, grief, and loss of control, often exacerbated by the secrecy surrounding their partner's status. Financial strains may also be more accentuated as one partner becomes ill and potentially less able or unable to work. [ 7 ]


Research involving serodiscordant couples has offered insights into how the virus is passed and how individuals who are HIV positive may be able to reduce the risk of passing the virus to their partner. [ 8 ]


Experts predict that there are thousands of serodiscordant couples in the  US  who wish to have children, [ 9 ]  and researchers report a growing stream of calls from these couples wanting reproductive help. [ 10 ]  The  Special Program of Assisted Reproduction  was developed in 1996 to help serodiscordant couples conceive safely, however, it is solely designed to help couples where the male partner is infected.


The  WHO 's consolidated guideline on sexual and reproductive health and rights for women living with HIV provides strategies to minimize HIV transmission risks in serodiscordant relationships when planning pregnancy. Key recommendations include  antiretroviral therapy  (ART) to suppress the viral load in the HIV-positive partner,  pre-exposure prophylaxis  (PrEP) for the HIV-negative partner, timing unprotected intercourse during peak fertility, screening and treating  sexually transmitted infections  in both partners, voluntary medical  male circumcision  for HIV-negative men, and assisted  reproductive techniques  such as semen  insemination . [ 11 ]


Sexology  is the scientific study of  human sexuality , including human sexual interests,  behaviors , and functions. [ 1 ]  The term  sexology  does not generally refer to the non-scientific study of sexuality, such as  social criticism . [ 2 ] [ 3 ]


Sexologists apply tools from several academic fields, such as  anthropology ,  biology ,  medicine ,  psychology ,  epidemiology ,  sociology , and  criminology . [ 4 ] [ 5 ]  Topics of study include  sexual development  (puberty),  sexual orientation ,  gender identity ,  sexual relationships , sexual activities,  paraphilias , and atypical sexual interests. It also includes the study of sexuality across the lifespan, including  child sexuality ,  puberty ,  adolescent sexuality , and  sexuality among the elderly . Sexology also spans sexuality among those with mental or physical disabilities. The sexological study of  sexual dysfunctions  and disorders, including  erectile dysfunction  and  anorgasmia , are also mainstays.


Sex manuals  have existed since antiquity, such as  Ovid 's  Ars Amatoria , the  Kama Sutra  of  Vatsyayana , the  Ananga Ranga , and  The Perfumed Garden for the Soul's Recreation .   De la prostitution dans la ville de Paris  ( Prostitution in the City of Paris ), an early 1830s study on 3,558 registered prostitutes in  Paris , written by Alexander Jean Baptiste Parent-Duchatelet (published in 1837, a year after he died), has been called the first work of modern sex research. [ 2 ]  In England,  James Graham  was an early sexologist who lectured on topics such as the process of sex and conception. [ 6 ]


The scientific study of sexual behavior in human beings began in the 19th century with  Heinrich Kaan , whose book  Psychopathia Sexualis  (1844)  Michel Foucault  describes as marking "the date of birth, or in any case the date of the emergence of sexuality and sexual aberrations in the psychiatric field." [ 7 ]  The term  sexology  was coined for the first time in the United States by Elizabeth Osgood Goodrich Willard in 1867. [ 8 ]  Roughly simultaneously a group of homophile activists, not yet identifying themselves as sexologists, were responding to shifts in  Europe 's national borders, a crisis that brought into conflict laws that were sexually liberal and laws that criminalized behaviors such as homosexual activity.


Despite the prevailing social attitude of sexual repression in  the Victorian era , the movement towards sexual emancipation began towards the end of the nineteenth century in England and Germany. In 1886,  Richard Freiherr von Krafft-Ebing  published  Psychopathia Sexualis .  That work is considered as having established sexology as a scientific discipline. [ 9 ]


In England, the founding father of sexology was the doctor and sexologist  Havelock Ellis  who challenged the  sexual taboos  of his era regarding  masturbation  and  homosexuality  and revolutionized the conception of sex in his time. His seminal work was the 1897  Sexual Inversion , which describes the sexual relations of homosexual males, including men with boys. Ellis wrote the first objective study of homosexuality (the term was coined by  Karl-Maria Kertbeny ), as he did not characterize it as a disease, immoral, or a crime. The work assumes that same-sex love transcended age  taboos  as well as gender taboos. Seven of his twenty-one case studies are of inter-generational relationships. He also developed other important psychological concepts, such as  autoerotism  and  narcissism , both of which were later developed further by  Sigmund Freud . [ 10 ]


Ellis pioneered  transgender  phenomena alongside the German  Magnus Hirschfeld . He established it as new category that was separate and distinct from homosexuality. [ 11 ]  Aware of Hirschfeld's studies of  transvestism , but disagreeing with his terminology, in 1913 Ellis proposed the term  sexo-aesthetic inversion  to describe the phenomenon. [ 12 ] [ 13 ]


In 1908, the first scholarly journal of the field,  Journal of Sexology  ( Zeitschrift für Sexualwissenschaft ), began publication and was published monthly for one year. Those issues contained articles by Freud,  Alfred Adler , and  Wilhelm Stekel . [ 3 ]  In 1913, the first academic association was founded: the  Society for Sexology . [ 14 ]


Freud developed a theory of sexuality. These  stages of development  include:  Oral ,  Anal ,  Phallic ,  Latency  and  Genital . These stages run from infancy to puberty and onwards. [ 15 ]  based on his studies of his clients, between the late 19th and early 20th centuries.  Wilhelm Reich  and  Otto Gross  were disciples of Freud, but rejected his theories [ vague ]  because of their emphasis on the role of sexuality in the revolutionary struggle for the emancipation of mankind.


Pre-Nazi Germany, under the sexually liberal  Napoleonic code , organized and resisted the anti-sexual, Victorian cultural influences. The momentum from those groups led them to coordinate sex research across traditional  academic disciplines , bringing Germany to the leadership of sexology. Physician  Magnus Hirschfeld  was an outspoken advocate for sexual minorities, founding the  Scientific Humanitarian Committee , the first advocacy for homosexual and transgender rights. [ 16 ]


Hirschfeld also set up the first  Institut für Sexualwissenschaft  (Institute for Sexology) in Berlin in 1919. [ 17 ]  Its library housed over 20,000 volumes, 35,000 photographs, a large collection of art and other objects. People from around Europe visited the institute to gain a clearer understanding of their  sexuality  and to be treated for their sexual concerns and dysfunctions.


Hirschfeld developed a system which identified numerous actual or hypothetical types of sexual intermediary between heterosexual male and female to represent the potential diversity of human sexuality, and is credited with identifying a group of people that today are referred to as  transsexual  or  transgender  as separate from the categories of homosexuality, he referred to these people as  transvestiten  (transvestites). [ 18 ] [ 19 ]  Germany's dominance in sexual behavior research ended with the  Nazi regime . [ 2 ]  The Institute and its library were destroyed by the Nazis less than three months after they took power, May 8, 1933. [ 3 ]  The institute was shut down and Hirschfeld's books were burned.


Other sexologists in the early  gay rights movement  included  Ernst Burchard  and  Benedict Friedlaender .  Ernst Gräfenberg , after whom the  G-spot  is named, published the initial research developing the  intrauterine device  (IUD).


After World War II, sexology experienced a renaissance, both in the United States and Europe. Large scale studies of sexual behavior, sexual function, and  sexual dysfunction  gave rise to the development of  sex therapy . [ 3 ]  Post-WWII sexology in the U.S. was influenced by the influx of European refugees escaping the Nazi regime and the popularity of the  Kinsey studies . Until that time, American sexology consisted primarily of groups working to end  prostitution  and to educate youth about  sexually transmitted infections . [ 2 ]   Alfred Kinsey  founded the  Institute for Sex Research  at  Indiana University  at  Bloomington  in 1947. This is now called the Kinsey Institute for Research in Sex, Gender and Reproduction. He wrote in his 1948 book that more was scientifically known about the sexual behavior of farm animals than of humans. [ 20 ]


Psychologist and sexologist  John Money  developed theories on sexual identity and  gender identity  in the 1950s. His work, notably on the  David Reimer  case has since been regarded as controversial, even while the case was key to the development of treatment protocols for  intersex  infants and children. [ 21 ] [ 22 ] [ vague ]


Kurt Freund  developed the  penile plethysmograph  in  Czechoslovakia  in the 1950s. The device was designed to provide an objective measurement of  sexual arousal  in males and is currently used in the assessment of  pedophilia  and  hebephilia . This tool has since been used with  sex offenders . [ 23 ] [ 24 ]


In 1966 and 1970,  Masters and Johnson  released their works  Human Sexual Response  and  Human Sexual Inadequacy,  respectively. Those volumes sold well, and they were founders of what became known as the  Masters & Johnson Institute  in 1978.


Vern Bullough  was a historian of sexology during this era, as well as being a researcher in the field. [ 25 ]


The emergence of  HIV/AIDS  in the 1980s caused a dramatic shift in sexological research efforts towards understanding and controlling the spread of the disease. [ 26 ] [ 27 ]


Technological advances have permitted sexological questions to be addressed with studies using behavioral genetics, [ 28 ]  neuroimaging, [ 29 ]  and large-scale Internet-based surveys. [ 30 ]


Sexology is a regulated profession in some jurisdictions. In Quebec, sexologists must be members of the Ordre professionnel des sexologues du Québec. They are one of the professions eligible to receive  psychotherapy  permits from the Ordre des psychologues du Québec. [ 31 ]


This is a list of sexologists and notable contributors to the field of sexology, by year of birth:


Sexual health clinics  specialize in the prevention and treatment of  sexually transmitted infections .


Sexual health clinics are also called  sexually transmitted disease  (STD) clinics ,  sexually transmitted infection (STI) clinics ,  venereal disease (VD) clinics , or  genitourinary medicine  (GUM) clinics . [ citation needed ]


Sexual health clinics differ from  reproductive health  and  family planning  clinics. Sexual health clinics offer only some reproductive health services. Reproductive health clinics, such as  Planned Parenthood , offer most of the services of sexual health clinics. [ citation needed ]


Sexual health clinics provide some or all of the following: [ citation needed ]


Many clinics provide vaccinations to prevent  infections  from the  hepatitis A  and  B   viruses . [ 1 ]
Young women may receive vaccinations to prevent infection from some strains of the  human papillomavirus  (HPV). [ citation needed ]


Many clinics provide  interpreting  for the hearing impaired or speakers of other languages. [ citation needed ]


Many clinics will help patients tell their sexual contacts if they have a sexually transmitted infection, anonymously if needed. [ 2 ]


Public governmental and  non-profit  clinics often provide services for free or adjust the fee based on a patient's ability to pay.
Sexual health clinics often offer services without appointments. Some clinics open evenings or weekends. Some clinics have separate hours or facilities for men and women. Some clinics serve only specific populations such as women, men,  MSM ,  youths ,  LGBT , ethnic groups, the poor, or students. [ citation needed ]


With the patient's  consent , a  clinician  will inspect the patient visually and by touch. If needed, the clinician will take samples to  test  for  sexually transmitted infections . [ citation needed ]


In a private room or space, the patient will partially undress. [ citation needed ]


The clinician may inspect the patient's: [ citation needed ]


The clinician may swab the patient's:


The clinician may take small blood samples by  pricking a finger  or from a  vein [ 4 ]  to test for  HIV ,  syphilis , and possibly  herpes [ 5 ]  and  hepatitis C . [ 6 ] [ 7 ] [ 8 ]


The clinician may ask for a small  urine  sample, given in private, to test for  chlamydia  and possibly  gonorrhea .
The inspections and taking samples do not hurt, but swabbing the urethra and cervix, and a finger prick blood sample feel uncomfortable.
Women will often receive a  pelvic exam , both external and internal, but usually less thorough than a reproductive health exam.
A patient can choose a female or male clinician if available.
A patient can have a  chaperone .
Some clinics have separate hours or facilities for men and women. [ citation needed ]


Medical  confidentiality  is an important part of the  medical ethics  of a  doctor–patient relationship . Sexual health clinics follow local standards of medical confidentiality to protect the privacy of patients. Some clinics provide anonymous services or protect confidentiality by having a patient use a number or a pseudonym. [ 9 ]


Additional privacy protections sometimes apply to matters of sexuality and reproduction, since these areas are sensitive in many cultures. The  diagnosis of HIV/AIDS  has legal restrictions in patient confidentiality, and some clinics use  rapid antibody tests  to provide results to a patient within 30 minutes, without holding the patient's records. [ citation needed ]


In the United States, clinics receiving federal funding from  Medicaid  or  Title X  of the  Public Health Service Act  must treat all patients confidentially. Thus minors can receive services without parental notification or consent. [ 10 ] [ 11 ] [ 12 ]  Additionally, medical records for all patients age 18 and above are strictly confidential under  HIPAA . [ 13 ]


Medical standards of  informed consent  apply to sexual health clinics. A patient needs information about the purposes and consequences of examinations, tests, treatments, and other procedures. A patient may then choose whether to consent to these procedures. [ citation needed ]


A  minor  may consent to receive some or all of the procedures at many sexual health clinics. [ citation needed ]


Sexually transmitted infections  ( STIs ), also referred to as  sexually transmitted diseases  ( STDs ), are  infections  that are commonly  spread  by  sexual activity , especially  vaginal intercourse ,  anal sex  and  oral sex . [ 1 ] [ 2 ]  The most prevalent STIs may be carried by a significant fraction of the human population.


The  subtypes of HIV  include two main subtypes, known as  HIV  type 1 (HIV-1) and HIV type 2 (HIV-2). These subtypes have distinct genetic differences and are associated with different  epidemiological  patterns and clinical characteristics.


HIV-1 exhibits a genetic relation to viruses indigenous to chimpanzees and gorillas that inhabit  West Africa , while HIV-2 viruses are affiliated with viruses present in the  sooty mangabey , a  vulnerable  West African primate. [ 2 ]


HIV-1 viruses can be further stratified into groups M, N, O, and P. Among these, HIV-1 group M viruses are the most prevalent, infecting nearly 90% of  people living with HIV  and are responsible for the global  AIDS pandemic . Group M can be further subdivided into subtypes based on  genetic sequence  data. Certain subtypes are known for their increased  virulence  or  drug resistance  to different medications used to treat HIV.


HIV-2 viruses are generally considered to be less virulent and less  transmissible  than HIV-1 M group viruses, although HIV-2 is also known to still cause AIDS.


One of the prevailing challenges in the pursuit of effective  management of HIV  is the virus's pronounced  genetic variability  and rapid  viral evolution . [ 3 ]


HIV-1 is the most common and most pathogenic strain of the virus. As of 2022 [update] , approximately 1.3 million such infections occur annually. [ 4 ] [ 5 ]  Scientists divide HIV-1 into a major group (group M) and two or more minor groups, namely groups N, O and possibly a group P. Each group is believed to represent an independent transmission of  simian immunodeficiency virus  (SIV) into humans, excluding subtypes within a specific group. [ 2 ]  The  complete genome sequence  of HIV-1 contains a total of 39  open reading frames  (ORFs) across all six possible  reading frames  (RFs), but only a few of them are functional. [ 6 ]


With 'M' for "major", this is by far the most common type of HIV, with more than 90% of HIV/AIDS cases caused by infection with HIV-1 group M viruses. This major HIV, which was the source of pre-1960 pandemic viruses, originated in the 1920s in  Léopoldville , the  Belgian Congo , today known as Kinshasa, which is now the capital of the  Democratic Republic of Congo  (DRC). [ 7 ]  Its  zoonotic origin  is the  SIVcpz  strain, which infects chimpanzees. The M group is subdivided further into  clades , called subtypes, that are also given a letter. There are also "circulating recombinant forms" or CRFs derived from  genetic recombination  between viruses of different subtypes which are in addition each given a number. CRF12_BF, for example, is a recombination between subtypes B and F. [ citation needed ]


The spatial movement of these subtypes moved along the railways and waterways of the DRC from Kinshasa to these other areas. [ 15 ]  These subtypes are sometimes further split into sub-subtypes such as A1 and A2 or F1 and F2. [ citation needed ]  In 2015, the HIV strain CRF19, a recombinant of subtype A, subtype D, and subtype G, with a subtype D  protease , was found to be strongly associated with rapid progression to AIDS in  Cuba . [ 16 ]  This is not thought to be a complete or final list, and further types are likely to be found. [ 17 ]


The 'N' stands for "non-M, non-O". [ 19 ]  This group was discovered by a Franco-Cameroonian team in 1998, when they identified and isolated the HIV-1 variant strain, YBF380, from a Cameroonian woman who died of AIDS in 1995. When tested, the YBF380 variant reacted with an  viral envelope   antigen  from SIVcpz rather than with those of Group M or Group O, indicating it was indeed a novel strain of HIV-1. [ 20 ]  As of 2015 [update] , fewer than 20 Group N infections have been recorded. [ 21 ]


The O ("Outlier") group has infected about 100,000 individuals located in West-Central Africa and is not usually seen outside of that area. [ 21 ]  It is reportedly most common in Cameroon, where a 1997 survey found that about 2% of HIV-positive samples were from Group O. [ 22 ]  Its zoonotic origin is SIVgor, which infects gorillas (rather than the more common source, SIVcpz). [ 23 ]  The group caused some concern because it could not be detected by early versions of the HIV-1 test kits. More advanced  HIV tests  have now been developed to detect both Group O and Group N. [ 24 ]


In 2009, a newly analyzed HIV sequence was reported to have greater similarity to SIVgor, than SIVcpz. The virus had been isolated from a Cameroonian woman residing in France who was diagnosed with HIV-1 infection in 2004. The scientists reporting this sequence placed it in a proposed Group P "pending the identification of further human cases". [ 25 ] [ 26 ] [ 27 ]


HIV-2 is mostly found in Africa, and therefore less recognized elsewhere in the world. The first identification of HIV-2 occurred in 1985 in Senegal by microbiologist  Souleymane Mboup  and his collaborators. [ 28 ]  The first case in the United States was in 1987. [ 29 ]  The first confirmed case of HIV-2 was a Portuguese man who was treated at the  London Hospital for Tropical Diseases  and later died in 1987. He was believed to have been exposed to the disease in  Guinea-Bissau  where he lived between 1956 and 1966. His pathological diagnosis at the time was  cryptosporidiosis  and  enterovirus infection , but an analysis of his stored  serum  in 1987 found that he was infected with HIV-2. [ 30 ]


Many test kits for HIV-1 will also detect HIV-2. [ 31 ]


There are eight known HIV-2 groups, designated A to H. Of these, only groups A and B are  pandemic . Group A is found mainly in West Africa, but has also spread to Angola, Mozambique, Brazil, India, Europe, and the US. Despite the presence of HIV-2 globally, Group B is mainly confined to West Africa. [ 32 ] [ 33 ]


HIV-2 is closely related to SIV endemic in  sooty mangabeys  ( Cercocebus atys atys ) (SIVsmm), a monkey species inhabiting the forests of Littoral West Africa.  Phylogenetic analyses  show that the virus most closely related to the two strains of HIV-2 which spread considerably in humans (HIV-2 groups A and B) is the SIVsmm found in the sooty mangabeys of the  Tai forest , in western  Ivory Coast . [ 32 ]


There are six additional known HIV-2 groups, each having been found in just one person. They all seem to derive from independent transmissions from sooty mangabeys to humans. Groups C and D have been found in two people from Liberia, groups E and F have been discovered in two people from Sierra Leone, and groups G and H have been detected in two people from the Ivory Coast. Each of these HIV-2 strains, for which humans are probably  dead-end hosts , is most closely related to SIVsmm strains from sooty mangabeys living in the same country where the human infection was found. [ 32 ] [ 33 ]


HIV-2 diagnosis can be made when a patient has no symptoms but positive blood work indicating the individual has HIV. The Multispot HIV-1/HIV-2 Rapid Test is currently the only FDA approved method for such differentiation between the two viruses. Recommendations for the screening and diagnosis of HIV has always been to use enzyme immunoassays that detect HIV-1, HIV-1 group O, and HIV-2. [ 34 ]  When screening the combination, if the test is positive followed by an indeterminate HIV-1  western blot , a follow-up test, such as  amino acid  testing, must be performed to distinguish which infection is present. [ 35 ]  According to the NIH, a differential diagnosis of HIV-2 should be considered when a person is of West African descent or has had sexual contact or shared needles with such a person. West Africa is at the highest risk as it is the origin of the virus. [ citation needed ]