Trichomoniasis

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Trichomoniasis (trich) is an infectious disease caused by the parasite Trichomonas vaginalis.<ref name=CDC2015>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> About 70% of affected people do not have symptoms when infected.<ref name=CDC2015/> When symptoms occur, they typically begin 5 to 28 days after exposure.<ref name=NIH2015/> Symptoms can include itching in the genital area, a bad smelling thin vaginal discharge, burning with urination, and pain with sex.<ref name=NIH2015/><ref name=CDC2015/> Having trichomoniasis increases the risk of getting HIV/AIDS.<ref name=NIH2015/> It may also cause complications during pregnancy.<ref name=NIH2015/>

Trichomoniasis is a sexually transmitted infection (STI) most often spread by vaginal, oral, or anal sex.<ref name=NIH2015/> It can also spread through genital touching (manual sex).<ref name=NIH2015/> Infected people may spread the disease even when symptoms are absent.<ref name=CDC2015/> Diagnosis is by finding the parasite in the vaginal fluid using a microscope, culturing the vaginal fluid or urine, or testing for the parasite's DNA.<ref name=NIH2015/> If present, other STIs should be tested for.<ref name=NIH2015/>

Methods of prevention include not having sex, using condoms, not douching, and being tested for STIs before having sex with a new partner.<ref name=NIH2015/> Although not caused by a bacterium, trichomoniasis can be cured with certain antibiotics (metronidazole, tinidazole, secnidazole).<ref name=NIH2015/> Sexual partners should also be treated.<ref name=NIH2015>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> About 20% of people get infected again within three months of treatment.<ref name=CDC2015/>

There were about 122 million new cases of trichomoniasis in 2015.<ref name=GBD2015Pre>Template:Cite journal</ref> In the United States, about 2 million women are affected.<ref name=NIH2015/> It occurs more often in women than men.<ref name=NIH2015/> Trichomonas vaginalis was first identified in 1836 by Alfred Donné.<ref>Template:Cite book</ref> It was first recognized as causing this disease in 1916.<ref>Template:Cite book</ref>

Signs and symptomsEdit

A single trichomonas by phase contrast microscopy

Most people infected with Trichomonas vaginalis do not have any symptoms and it can be undetected for years.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Symptoms include pain, burning or itching in the penis, urethra (urethritis), or vagina (vaginitis). Discomfort for both sexes may increase during intercourse and urination. For women, there may also be a yellow-green, itchy, frothy, foul-smelling ("fishy" smell) vaginal discharge. In rare cases, lower abdominal pain can occur. Symptoms usually appear within 5 to 28 days of exposure.<ref name="Trichomoniasis symptoms">Trichomoniasis symptoms Template:Webarchive. cdc.gov</ref> Sometimes trichomoniasis can be confused with chlamydia because the symptoms are similar.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

ComplicationsEdit

Trichomoniasis is linked to several serious complications.

Trichomoniasis is associated with an increased risk of transmission and infection of HIV.<ref name=Secor /><ref>Template:Cite journal</ref>
Trichomoniasis may cause a woman to deliver a low-birth-weight or premature infant.<ref name=Secor />
The role of Trichomonas infection in causing cervical cancer is unclear. However, trichomonas infection may be associated with co-infection with high-risk strains of HPV.<ref>Template:Cite journal</ref>
T. vaginalis infection in males has been found to cause asymptomatic urethritis and prostatitis. In the prostate, it may create chronic inflammation that may eventually lead to prostate cancer.<ref name="CainiGandini2014">Template:Cite journal</ref><ref name=pmid19741211>Template:Cite journal</ref>

CausesEdit

File:Trichomoniasis 01.png

Lifecycle of Trichomonas

The human genital tract is the only reservoir for this species. Trichomonas is transmitted through sexual or genital contact.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

The single-celled protozoan produces mechanical stress on host cells and then ingests cell fragments after cell death.<ref>Template:Cite journal</ref>

Genetic sequenceEdit

A draft sequence of the Trichomonas genome was published on January 12, 2007, in the journal Science, confirming that the genome has at least 26,000 genes, a similar number to the human genome. An additional approximately 34,000 unconfirmed genes, including thousands that are part of potentially transposable elements, brings the gene content to well over 60,000.<ref>Scientists crack the genome of the parasite causing trichomoniasis Template:Webarchive. Physorg.com. Jan. 12, 2007.</ref>

DiagnosisEdit

There are three main ways to test for trichomoniasis.

The first is known as saline microscopy. This is the most commonly used method and requires an endocervical, vaginal, or penile swab specimen for examination under a microscope.<ref>Template:Cite book</ref> The presence of one or multiple trichomonads constitutes a positive result. This method is cheap but has a low sensitivity (60–70%) often due to an inadequate sample, resulting in false negatives.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
The second diagnostic method is culture, which has historically been the "gold standard" in infectious disease diagnosis. Trichomonas vaginalis culture tests are relatively cheap but their sensitivity is still somewhat low (70–89%).<ref name="ReferenceA">Template:Cite journal</ref>
The third method includes the nucleic acid amplification tests (NAATs), which are more sensitive.<ref name="ReferenceA"/> These tests are more costly than microscopy and culture, and are highly sensitive (80–90%).<ref name="Ginocchio C 2601">Template:Cite journal</ref>

PreventionEdit

Use of male condoms or female condoms may help prevent the spread of trichomoniasis,<ref>Vaginitis/Trichomoniasis: Reduce your risk Template:Webarchive, American Social Health Association. Retrieved March 12, 2008.</ref> although careful studies have never been done on how to prevent this infection. Infection with trichomoniasis through water is unlikely because Trichomonas vaginalis dies in water after 45–60 minutes, in thermal water after 30 minutes to 3 hours, and in diluted urine after 5–6 hours.<ref name="gynekologie"/>

There are no routine standard screening requirements for the general U.S. population receiving family planning or STI testing.<ref name=munson>Template:Cite journal</ref><ref name=wendel>Template:Cite journal</ref> The Centers for Disease Control and Prevention (CDC) recommends trichomoniasis testing for females with vaginal discharge<ref name="Workowski KA 2010">Template:Cite journal</ref> and can be considered for females at higher risk for infection or of HIV-positive serostatus.<ref name="munson"/>

The advent of new, highly specific, and sensitive trichomoniasis tests presents opportunities for new screening protocols for both men and women.<ref name=munson /><ref name=smith>Template:Cite journal</ref> Careful planning, discussion, and research are required to determine the cost-efficiency and most beneficial use of these new tests for the diagnosis and treatment of trichomoniasis, which can lead to better prevention efforts.<ref name=munson /><ref name=smith />

Several strategies have been found to improve follow-up for STI testing, including email and text messaging as reminders of appointments.<ref name="DesaiWoodhall2015">Template:Cite journal</ref>

ScreeningEdit

Evidence from randomized controlled trials for screening pregnant women who have no symptoms of infection with trichomoniasis and treating women who test positive for the infection have not consistently shown a reduced risk of preterm birth.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> Further studies are needed to verify this result and determine the best method of screening. In the U.S., screening of pregnant women without symptoms is recommended only for those with HIV, as Trichomonas infection is associated with an increased risk of transmitting HIV to the fetus.<ref name=":0" />

TreatmentEdit

Treatment for both pregnant and non-pregnant women is usually with metronidazole,<ref>Vaginitis/Trichomoniasis :Treatment for trichomoniasis Template:Webarchive, American Social Health Association. Retrieved March 12, 2008.</ref> by mouth once.<ref name=":0">Template:Cite journal</ref> Caution should be used in pregnancy, especially in the first trimester.<ref name="pmid15489348">Template:Cite journal</ref> Sexual partners, even if they have no symptoms, should also be treated.<ref name="gynekologie">Template:Cite book</ref> Single oral dose of nitroimidazole is sufficient to kill the parasites.<ref>Template:Cite journal</ref>

For 95–97% of cases, infection is resolved after one dose of metronidazole.<ref name="Workowski KA 2010"/><ref>Template:Cite journal</ref> Studies suggest that 4–5% of trichomonas cases are resistant to metronidazole, which may account for some "repeat" cases.<ref name="pmid15489348"/><ref name=Secor>Template:Cite journal</ref> Without treatment, trichomoniasis can persist for months to years in women, and is thought to improve without treatment in men.<ref name=Secor /> Women living with HIV infection have better cure rates if treated for seven days rather than with one dose.<ref name=":0" /><ref>Template:Cite journal</ref>

Topical treatments are less effective than oral antibiotics due to Skene's gland and other genitourinary structures acting as reservoirs.<ref>Template:Cite journal</ref>

Vaginal boric acid can be useful against resistant trichomoniasis.<ref name="LærkeholmMüllerDamstedPetersenSaunte2024">Template:Cite journal</ref><ref name="ThorleyRoss2018">Template:Cite journal</ref><ref name="MittelstaedtKretzLevine2021">Template:Cite journal</ref>

EpidemiologyEdit

There were about 58 million cases of trichomoniasis in 2013.<ref name=GBD2015>Template:Cite journal</ref> It is more common in females (2.7%) than males (1.4%).<ref name=LancetEpi2012>Template:Cite journal</ref> It is the most common non-viral STI in the U.S., with an estimated 3.7 million prevalent cases and 1.1 million new cases per year.<ref>Centers for Disease Control and Prevention, National Center for HIV/AIDS, Viral Hepatitis, and TB. Division of STD Prevention. Trichomoniasis - CDC Fact Sheet. 2012.</ref><ref>Template:Cite journal</ref> It is estimated that 3% of the general U.S. population is infected,<ref name="Ginocchio C 2601"/><ref name="pmid17968828">Template:Cite journal</ref> and 7.5–32% of moderate-to-high risk (including incarcerated) populations.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>