In 2010, 19 million new cases of sexually transmitted infections occurred in women in the United States. A 2008 CDC study found that 25–40% of U.S. teenage girls has a sexually transmitted disease.
The World Health Organization (WHO) has recommended the more inclusive term sexually transmitted infection since 1999. Public health officials originally introduced the term sexually transmitted infection, which clinicians are increasingly using alongside the term sexually transmitted disease in order to distinguish it from the former.
The soil-transmitted helminths (also called geohelminths) are a group of intestinal parasites belonging to the phylum Nematoda that are transmitted primarily through contaminated soil. They are so called because they have a direct life cycle which requires no intermediate hosts or vectors, and the parasitic infection occurs through faecal contamination of soil, foodstuffs and water supplies. The adult forms are essentially parasites of humans, causing soil-transmitted helminthiasis (STH), but also infect domesticated mammals. The juveniles are the infective forms and they undergo tissue-migratory stages during which they invade vital organs such as lungs and liver. Thus the disease manifestations can be both local and systemic. The geohelminths together present an enormous infection burden on humanity, amounting to 135,000 deaths every year, and persistent infection of more than two billion people.
A Transfusion transmitted infection (TTI) is a virus, parasite, or other potential pathogen that can be transmitted in donated blood through a transfusion to a recipient. The term is usually limited to known pathogens, but also sometimes includes agents such as Simian foamy virus which are not known to cause disease.
Hepatitis B may also be classified as a vertically transmitted infection. The hepatitis B virus is large and does not cross the placenta. Hence, it cannot infect the fetus unless breaks in the maternal-fetal barrier have occurred, but such breaks can occur in bleeding during childbirth or amniocentesis.
In 2008, it was estimated that 500 million people were infected with either syphilis, gonorrhea, chlamydia or trichomoniasis. At least an additional 530 million people have genital herpes and 290 million women have human papillomavirus. STIs other than HIV resulted in 142,000 deaths in 2013. In the United States there were 19 million new cases of sexually transmitted infections in 2010.
TTV, for transfusion transmitted virus or torque teno virus was first reported in a Japanese patient in 1997 by the research scientist T. Nishizawa. The virus is extremely common, even in healthy individuals—as much as 100% prevalent in some countries, and in approximately 10% of blood donors in the UK and the US. Although it does not appear to cause symptoms of hepatitis on its own, it is often found in patients with liver disease. For the most part, TTV infection is believed to be asymptomatic.
Some vertically transmitted infections, such as toxoplasmosis and syphilis, can be effectively treated with antibiotics if the mother is diagnosed early in her pregnancy. Many viral vertically transmitted infections have no effective treatment, but some, notably rubella and varicella-zoster, can be prevented by vaccinating the mother prior to pregnancy.
Babies can also become infected by their mothers during birth. Some infectious agents may be transmitted to the embryo or fetus in the uterus, while passing through the birth canal, or even shortly after birth. The distinction is important because when transmission is primarily during or after birth, medical intervention can help prevent infections in the infant.
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. Many times STIs initially do not cause symptoms. This results in a greater risk of passing the disease on to others. Symptoms and signs of disease may include vaginal discharge, penile discharge, ulcers on or around the genitals, and pelvic pain. STIs can be transmitted to an infant before or during childbirth and may result in poor outcomes for the baby. Some STIs may cause problems with the ability to get pregnant.
The main routes of transmission of vertically transmitted infections are across the placenta (transplacental) and across the female reproductive tract during childbirth. Transmission is also possible by breaks in the maternal-fetal barrier such by amniocentesis or major trauma.
Babesia microti is transmitted by ixodes ticks. There are few studies which documents transmission of babesiosis through blood transfusion.
Some STIs such as HIV can be transmitted from mother to child either during pregnancy or breastfeeding.
In the 1996 sexual harassment case filed against Mitsubishi Motor Manufacturing of America by the Equal Employment Opportunity Commission (EEOC), a number of male employees referred to sexually transmitted infections as "souvenirs".
The large number of epidemiological studies permitted to clearly point out the global distribution of the virus (Africa, North and South America, Asia, Europe, Oceania) in rural and urban populations. Despite that the link between TTV infection and a given pathology has not been shown, the hypothesis of a relation between viral load and the immune status of the host was suggested. Moreover, although initially suspected to be transmitted only by blood transfusion, the global dispersion of the virus in populations and its detection in various biologic samples (plasma, saliva, feces, etc...) suggest combined modes of diffusion, and in particular the spread by saliva droplets. Sexual transmission has also been proposed.
Prior to the invention of modern medicines, sexually transmitted diseases were generally incurable, and treatment was limited to treating the symptoms of the disease. The first voluntary hospital for venereal diseases was founded in 1746 at London Lock Hospital. Treatment was not always voluntary: in the second half of the 19th century, the Contagious Diseases Acts were used to arrest suspected prostitutes. In 1924, a number of states concluded the Brussels Agreement, whereby states agreed to provide free or low-cost medical treatment at ports for merchant seamen with venereal diseases.
During birth, babies are exposed to maternal blood, body fluids, and to the maternal genital tract without the placental barrier intervening. Because of this, blood-borne microorganisms (hepatitis B, HIV), organisms associated with sexually transmitted diseases (e.g., Neisseria gonorrhoeae and Chlamydia trachomatis), and normal fauna of the genitourinary tract (e.g., Candida albicans) are among those commonly seen in infection of newborns.
The signs and symptoms of a vertically transmitted infection depend on the individual pathogen. In the mother, it may cause subtle signs such as an influenza-like illness, or possibly no symptoms at all. In such cases, the effects may be seen first at birth.
Preventing the spread of these diseases by blood transfusion is addressed in several ways. In many cases, the blood is tested for the pathogen, sometimes with several different methodologies. Donors of blood are also screened for signs and symptoms of disease and for activities that might put them at risk for infection. If a local supply is not safe, blood may be imported from other areas. Human immunodeficiency virus (HIV) leads to the best known of the transfusion transmitted diseases, acquired immune deficiency syndrome (AIDS).
A vertically transmitted infection is an infection caused by pathogens (such as bacteria and viruses) that use mother-to-child transmission, that is, transmission directly from the mother to an embryo, fetus, or baby during pregnancy or childbirth. It can occur when the mother gets an infection as an intercurrent disease in pregnancy. Nutritional deficiencies may exacerbate the risks of perinatal infections.