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Sexually transmitted infection

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Sexually transmitted infection
SpecialtyInfectious diseases Edit this on Wikidata

A sexually transmitted disease (STD) or venereal disease (VD), is an illness that has a significant probability of transmission between humans or animals by means of sexual contact, including vaginal intercourse, oral sex, and anal sex. Increasingly, the term sexually transmitted infection (STI) is used, as it has a broader range of meaning; a person may be infected, and may potentially infect others, without showing signs of disease. Some STIs can also be transmitted via use of an IV drug needle after its use by an infected person, as well as through childbirth or breastfeeding. Sexually transmitted infections have been well known for hundreds of years.

Classification and terminology

Until the 1990s, STDs were commonly known as venereal diseases : Veneris is the Latin genitive form of the name Venus, the Roman goddess of love. Social disease was another euphemism.

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. According to Ethiopian Aids Resource Center FAQ - Are sexually transmitted infections (STIs) different from sexually transmitted diseases (STDs)?, "Sometimes the terms STI and STD are used interchangeably. This can be confusing and not always accurate, so it helps first to understand the difference between infection and disease. Infection simply means that a germ — virus, bacteria, or parasite — that can cause disease or sickness if present inside a person’s body. An infected person does not necessarily have any symptoms or signs that the virus or bacteria is actually hurting his or her body; they do not necessarily feel sick. A disease means that the infection is actually causing the infected person to feel sick, or to notice something is wrong. For this reason, the term STI — which refers to infection with any germ that can cause an STD, even if the infected person has no symptoms — is a much broader term than STD." The distinction being made, however, is closer to that between a colonization and an infection, rather than between an infection and a disease.

Specifically, the term STD refers only to infections that are causing symptoms. Because most of the time people do not know that they are infected with an STD until they start showing symptoms of disease, most people use the term STD, even though the term STI is also appropriate in many cases.

Moreover, the term sexually transmissible disease is sometimes used since it is less restrictive in consideration of other factors or means of transmission. For instance, meningitis is transmissible by means of sexual contact but is not labeled as an STI because sexual contact is not the primary vector for the pathogens that cause meningitis. This discrepancy is addressed by the probability of infection by means other than sexual contact. In general, an STI is an infection that has a negligible probability of transmission by means other than sexual contact, but has a realistic means of transmission by sexual contact (more sophisticated means — blood transfusion, sharing of hypodermic needles —are not taken into account). Thus, one may presume that, if a person is infected with an STI, e.g., chlamydia, gonorrhea, genital herpes, it was transmitted to him/her by means of sexual contact.

The English language has short words for two of the most common: "pox" (syphilis) and "the clap" (gonorrhea).


Prevalence

STD incidence rates remain high in most of the world, despite diagnostic and therapeutic advances that can rapidly render patients with many STDs noninfectious and cure most. In many cultures, changing sexual morals and oral contraceptive use have eliminated traditional sexual restraints, especially for women, and both physicians and patients have difficulty dealing openly and candidly with sexual issues. Additionally, worldwide dissemination of drug-resistant bacteria (e.g., penicillin-resistant gonococci) reflects misuse of antibiotics and spread of resistant clones by mobile populations. The effect of travel is most dramatically illustrated by the rapid spread of the AIDS virus (HIV-1) from Africa to Europe and the Americas in the late 1970s.[1]

Commonly reported prevalences of STIs among sexually active adolescent girls both with and without lower genital tract symptoms include chlamydia trachomatis (10 to 25%), Neisseria gonorrhoeae (3 to 18%), syphilis (0 to 3%), Trichomonas vaginalis (8 to 16%), and herpes simplex virus (2 to 12%).[citation needed] Among adolescent boys with no symptoms of urethritis, isolation rates include C. trachomatis (9 to 11%) and N. gonorrhoeae (2 to 3%).[citation needed]

In 1996, WHO estimated that more than 1 million people were being infected daily. About 60% of these infections occur in young people <25 years of age, and of these 30% are <20 years. Between the ages of 14 and 19, STDs occur more frequently in girls than boys by a ratio of nearly 2:1; this equalizes by age 20. An estimated 340 million new cases of syphilis, gonorrhea, chlamydia and trichomoniasis occurred throughout the world in 1999.[2][3]

Prevention

Main article: Safe sex

The most effective way to prevent sexual transmission of STIs is to avoid contact of body parts or fluids which can lead to transfer, not necessarily any sexual activity with an infected partner. No contact equals no risk. Not all sexual activities involve contact: cybersex, phonesex or masturbation from a distance are methods of avoiding contact. Ideally, both partners should get tested for STIs before initiating sexual contact, or if a partner engaged in contact with someone else, but even then, certain STIs, particularly certain persistent viruses like HPV, may be impossible to detect with current medical procedures as they may be asymptomatic. Prevention is also key in addressing viral STIs such as HIV & herpes, as they are currently incurable. Many diseases that establish permanent infections can so occupy the immune system that other diseases become more easily transmitted.

Vaccines are available that protect against some viral STIs, such as Hepatitis B and some types of HPV. Vaccination before initiation of sexual contact is advised to assure maximal protection.

The innate immune system led by defensins against HIV can prevent transmission of HIV when viral counts are very low, but if busy with other viruses or overwhelmed, HIV can establish itself. Certain viral STI's also greatly increase the risk of death for HIV infected patients.

Condoms

Condoms only provide protection when used properly as a barrier, and only to and from the area that it covers. Uncovered areas are still susceptible to many STDs. In the case of HIV, sexual transmission routes almost always involve the penis, as HIV cannot spread through unbroken skin, thus properly shielding the insertive penis with a properly worn condom from the vagina and anus effectively stops HIV transmission. An infected fluid to broken skin borne direct transmission of HIV would not be considered "sexually transmitted", but can still theoretically occur during sexual contact, this can be avoided simply by not engaging in sexual contact when having open bleeding wounds. Other STDs, even viral infections, can be prevented with the use of latex condoms as a barrier. Some microorganisms and viruses are small enough to pass through the pores in natural skin condoms, but are still too large to pass through latex condoms.

Condoms are designed, tested, and manufactured to never fail if used properly. There has not been one documented case of an HIV transmission due to an improperly manufactured condom.[dubious – discuss] However, there have been cases of condom recall, as in a case in South Africa.[4]

Proper usage entails:

  • Not putting the condom on too tight at the end, and leaving 1.5 cm (3/4 inch) room at the tip for ejaculation. Putting the condom on snug can and often does lead to failure.
  • Wearing a condom too loose can defeat the barrier.
  • Avoiding inverting, spilling a condom once worn, whether it has ejaculate in it or not, even for a second.
  • Avoiding condoms made of substances other than latex or polyurethane, as they don't protect against HIV.
  • Avoiding the use of oil based lubricants (or anything with oil in it) with latex condoms, as oil can eat holes into them.
  • Using flavored condoms for oral sex only, as the sugar in the flavoring can lead to yeast infections if used to penetrate.

Not following the first five guidelines above perpetuates the common misconception that condoms aren't tested or designed properly.

In order to best protect oneself and the partner from STI's, the old condom and its contents should be assumed to be still infectious. Therefore the old condom must be properly disposed of. A new condom should be used for each act of intercourse, as multiple usage increases the chance of breakage, defeating the primary purpose as a barrier. Defeated barrier equals potential transmission.

Testing

Main article: STD testing

Treatment history

American poster propaganda targeted at World War II soldiers and sailors appealed to their patriotism in urging them to protect themselves. The text at the bottom of the poster reads, "You can't beat the Axis if you get VD." Images of women were used to catch the eye on many VD posters.
File:Stdspain.jpg
Spanish Civil War poster, produced by the Republican government, saying "Avoid venereal diseases ... As dangerous as enemy bullets"

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.[5]

The first effective treatment for a sexually transmitted disease was salvarsan, a treatment for syphilis. With the discovery of antibiotics, a large number of sexually transmitted diseases became easily curable, and this, combined with effective public health campaigns against STDs, led to a public perception during the 1960s and 1970s that they have ceased to be a serious medical threat.

During this period, the importance of contact tracing in treating STIs was recognized. By tracing the sexual partners of infected individuals, testing them for infection, treating the infected and tracing their contacts in turn, STI clinics could be very effective at suppressing infections in the general population.

In the 1980s, first genital herpes and then AIDS emerged into the public consciousness as sexually transmitted diseases that could not be cured by modern medicine. AIDS in particular has a long asymptomatic period — during which time HIV (the human immunodeficiency virus, which causes AIDS) can replicate and the disease can be transmitted to others — followed by a symptomatic period, which leads rapidly to death unless treated. Recognition that AIDS threatened a global pandemic led to public information campaigns and the development of treatments that allow AIDS to be managed by suppressing the replication of HIV for as long as possible. Contact tracing continues to be an important measure, even when diseases are incurable, as it helps to contain infection.

Types and their pathogenic causes

Most of the diseases on this list are most commonly transmitted sexually. Some are commonly transmitted in other ways as well; for example, HIV/AIDS is also commonly transmitted through the sharing of infected needles by drug users, while SARS, which can be spread through casual contact such as coughing and sneezing, is very often not associated with sexual activity.

Bacterial

Fungal

Viral

  • Cytomegalovirus (CMV) through skin to skin contact, saliva, not only sexually.

Parasites

Protozoal

Sexually transmitted enteric infections

Various bacterial (Shigella, Campylobacter, or Salmonella), viral (Hepatitis A), or parasitic (Giardia or amoeba) pathogens are transmitted by sexual practices that promote anal-oral contamination. Sharing sex toys without washing or multiple partnered barebacking can promote anal-anal contamination. Although the bacterial pathogens may coexist with or cause proctitis, they usually produce symptoms (diarrhea, fever, bloating, nausea, and abdominal pain) suggesting disease more proximal in the GI tract.

Sexually transmissible oral infections

Common colds, influenza, Staphylococcus aureus, E. coli, Adenoviruses, Human Papillomavirus, Oral Herpes (1, 2, 4, 5, 8) and the yeast Candida albicans can all be transmitted through the oral route.

See also

References

  1. ^ Mary-Ann Shafer, Anna-Barbara Moscicki (2006). "Sexually Transmitted Infections, 2006": 1–8. {{cite journal}}: Cite journal requires |journal= (help); External link in |title= (help)
  2. ^ STD Statistics Worldwide
  3. ^ U.S. Medicine Information Central
  4. ^ Condom recall hits South African AIDS campaign - CNN.com
  5. ^ Archives in London and the M25 area (AIM25) London Lock Hospital records
  6. ^ Cook H, Furuya E, Larson E, Vasquez G, Lowy F (2007). "Heterosexual transmission of community-associated methicillin-resistant Staphylococcus aureus". Clin Infect Dis. 44 (3): 410–3. doi:10.1086/510681. PMID 17205449.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ Workowski K, Berman S (2006). "Sexually transmitted diseases treatment guidelines, 2006". MMWR Recomm Rep. 55 (RR-11): 1–94. PMID 16888612. {{cite journal}}: External link in |title= (help)
  8. ^ Wu J, Chen C, Sheen I, Lee S, Tzeng H, Choo K (1995). "Evidence of transmission of hepatitis D virus to spouses from sequence analysis of the viral genome". Hepatology. 22 (6): 1656–60. PMID 7489970.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ Farci P. "Delta hepatitis: an update". J Hepatol. 39 Suppl 1: S212–9. PMID 14708706.
  10. ^ Shukla N, Poles M (2004). "Hepatitis B virus infection: co-infection with hepatitis C virus, hepatitis D virus, and human immunodeficiency virus". Clin Liver Dis. 8 (2): 445–60, viii. doi:10.1016/j.cld.2004.02.005. PMID 15481349.
  11. ^ Alzheimer's linked to cold sores: study - ABC News (Australian Broadcasting Corporation)

External links

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