Trichomoniasis is a common sexually transmitted infection (STI) caused by Trichomonas vaginalis, a parasitic protozoan. Present worldwide, this STI affects men and women with the latter experiencing symptoms at much higher rates.
Approximately 50% of females infected with trichomoniasis do not experience symptoms   with a third of these women going on to develop symptoms within 6 months . Furthermore, almost all infected males are asymptomatic  .
The clinical presentation in symptomatic females features a copious vaginal secretion characterized by yellow-green and frothy looking discharge, which may be accompanied by vulvar and perineal soreness, dyspareunia, and dysuria. Furthermore, the vaginal tissue and cervix may be covered by "strawberry" spots. Additionally, some women may develop urethritis or cystitis. Note that asymptomatic patients may manifest with signs as the vulva and perineum undergo inflammation and the labia becomes edematous.
While almost all males are asymptomatic, some men will have a urethral discharge of frothy or purulent secretion, pain and irritation after ejaculation and dysuria often in the morning. The urethritis is usually mild. Rare sequelae include epididymitis open link and prostatitis.
Controlling this STI is important as trichomoniasis is associated with complications and a high risk for contracting other diseases . Hence, a timely manner of diagnosis is important.
Clinical evaluation of symptomatic patients includes a medical and social/sexual history, physical/pelvic exam, and laboratory testing.
Clinicians may use one of the several studies to diagnose trichomoniasis. The common test, wet preparation, can be rapidly performed in the outpatient setting. However, the sensitivity of this test is 60% to 70% . Additionally, the gold standard diagnostic technique is a culture of the organism with media such as Diamond's, Trichosel, and InPouch TV.
Novel diagnostic methods include polymerase chain reaction (PCR) assays which yield high sensitivity and specificity. Additionally, PCR assays are critical for tracking prevalence and morbidity  . PCR assay of vaginal swabs is preferred to PCR assay of urine .
There are two point-of-care tests for detection of trichomoniasis in vaginal secretions. These are the OSOM Trichomonas Rapid Test and the Affirm VP III. The former is a Genzyme Diagnostics product that functions as an immunochromatographic capillary-flow enzyme immunoassay that produces results in about 10 minutes. The latter is a Becton Dickenson technology that specializes as a nucleic acid probe test that detects T. vaginalis, Gardnerella vaginalis, and Candida albicans in approximately 45 minutes. These FDA-approved tests exhibit a sensitivity greater than 83% and a specificity greater than 97%    and can provide results in a timely manner.
The Papanicolaou smear is not a screening test for trichomoniasis since it has a poor sensitivity as well as a time delay to diagnosis of the infection occurs.
The recommended treatment for trichomoniasis is a single dose of metronidazole or tinidazole at 2 grams taken orally. This cures as much as 95% of females when their sexual partners are treated concurrently. The alternative regimen is metronidazole or tinidazole at a dose of 500 mg taken orally twice a day for 5 to 7 days.
For women not successfully responding to medication, they can be managed again with one of the regimens stated above. If still not cured, then the regimen is metronidazole or tinidazole at 2 grams daily for 5 days. Note that reinfection by sexual partners should be excluded when evaluating those with failed treatment.
Treatment of sexual partners
The patient's sexual partner(s) should be evaluated and treated in order to cure and contain the infection as well as to prevent its transmission. The therapy is the same as that of the patient. Additionally, partners should be screened for other STIs as well.
Due to the high reinfection rate, women should have a diagnostic check-up within 3 months of treatment.
Other special considerations
The clinician should counsel patients on how to modify sexual behavior. For example, infected individuals and their partners are strongly advised to abstain from sexual intercourse until the therapy has been completed and the symptoms have resolved . Moreover, testing for other STIs such as HIV should be performed. Also, patients should be advised about the importance of barrier contraceptives.
Drug side effects
The recommended therapy is metronidazole, which has demonstrated a 90% to 95% cure rate . Furthermore, treatment of sexual partners may result in an even higher success rate.
Sexually active patients will commonly experience a recurrence. In fact, one study reported that 17% of patients were found to be reinfected at their 3-month follow-up appointments .
The cause of trichomoniasis is the organism T. vaginalis as the mode of transmission is through sexual intercourse. There are risk factors for this infection which include having 1) new or multiple sexual partners, 2) a current episode or history of STIs, 3) sexual contact with a currently infected partner, and 4) absent use of barrier contraception.
Additionally, behaviors such as prostitution and intravenous drug use also place individuals at higher risk of contracting this disease. On fact, according to a study that assessed risk factors, the most predominant risk factor is drug use in the month preceding the infection .
This STI is prevalent in the United States at a high rate as an estimated 3.7 million individuals are infected, of which approximately 30% are symptomatic. Furthermore, trichomoniasis has a preference for females at likely older ages.
Trichomoniasis is transmitted during sexual intercourse, in which the parasite tends to infect the lower genital tract including the vulva, vagina, or urethra in women and the urethra in men. Moreover, T. vaginalis is the most frequently isolated organism from vaginal secretions and male urethral secretions. The parasite can infect hands, mouth or anus, however, very few cases have been reported .
While it is unknown why a majority of infected patients do not produce symptoms, it is likely that age and health play a role. It is important to note that asymptomatic individuals can also infect others.
Trichomoniasis is frequently found with other STIs such as gonorrhea , chlamydia, herpes, and others as well. In fact, an infection with T. vaginalis leads to genital inflammation and hence increases the patient's susceptibility to herpes, human papillomavirus (HPV), and HIV . Regarding HIV, individuals with trichomoniasis are at increased risk of developing this viral disease in comparison to the general population .
Additionally, this STI is associated with a greater risk of pelvic inflammatory disease (PID)  and tubal infertility .
With regards to pregnant women infected with trichomoniasis, they are at greater risk for preterm delivery, premature rupture of membranes, intrauterine infection, and delivering a neonate with low birth weight .
The parasitic action results in stress in the host cells leading to cellular damage.
Abstinence is the only method to prevent getting STIs. Moreover, minimizing the risk of contracting and spreading STIs is dependent on safe sex practice. For example, sexually active individuals should use latex condoms every time they engage in sexual intercourse to decrease the probability of transmitting not only trichomoniasis but all STIs. Diaphragms may also be useful but should not be the only protective method  while spermicides are not effective. In fact, the latter may be linked to a higher risk of STIs such as HIV .
Additionally, partners should communicate with each other about STIs and risks. They should also disclose to each other about current infections as it is important that all parties have the opportunity to make informed decisions regarding their sexual activities. Another safe practice is to limit the number of sexual partners.
Finally, patients with symptoms or any signs of infection should seek medical attention. Their partners must also receive care and treatment.
Trichomoniasis is one of the most prevalent sexually transmitted infections (STI) globally  . The organism responsible for this disease is the motile protozoan Trichomonas vaginalis. Since it is frequently present with other STIs and is associated with serious sequelae such as pregnancy complications, infertility, cervical neoplasia and postoperative infections , trichomoniasis represents a public health issue. Hence, there is a sense of urgency regarding the diagnosis and treatment of this infection.
The clinical presentation for infected women varies as half are asymptomatic while others experience foul-smelling vaginal discharge among other signs. Infected men typically manifest no symptoms although a few may have urethritis and penile discharge.
Any woman with foul-smelling, thin vaginal discharge should be tested for trichomonas and other STIs. Additionally, those at high risk for STIs should be screened as well . Hence, evaluation of the patient includes a medical and sexual/social history, pelvic exam, and laboratory testing. The latter includes wet mount microscopy, culture, or certain point-of-care tests. The choice of study depends on the availability and cost.
Treatment is required for infected individuals and their sexual partners. The recommended regimen is oral metronidazole. Additionally, patients and their partners should avoid sexual intercourse until treatment is completed and symptoms have disappeared.
Only abstinence can prevent one from this infection. However, the risk of contracting and transmitting STIs can be minimized with the use of latex condoms. Additionally, all individuals are advised to adhere to safe sex practice.
What are the signs and symptoms?
While almost half of infected women do not have any symptoms, those that do may experience the following:
The vast majority of men do not have any symptoms. Those that do have symptoms may experience the following:
How is it diagnosed?
Women who seek care for vaginal discharge and other similar symptoms should be tested for trichomoniasis and other sexually transmitted diseases. The health care provider should obtain the medical and sexual history of the patient. Also, a pelvic exam should be performed. Very importantly, there are a number of tests that can be done to diagnose this infection. The provider will commonly take a sample of the discharge, apply it on a slide, and evaluate it microscopically to detect the causative organism.
How is it treated?
Metronidazole, or Flagyl, is the recommended treatment for infected patients and their partners. It can be given in a large single dose orally or in smaller doses over 5 to 7 days. Tinidazole is an alternative to metronidazole.
Patients and their partners should abstain from sexual intercourse until treatment is completed and symptoms have disappeared. Additionally, women should have follow-up within 3 months to ensure the infection has been cured.
Note that these medications should not be taken with alcohol. Also, there are serious but uncommon side effects associated with these medications.
Why is it important to treat this infection?
Trichomoniasis is often found with chlamydia, gonorrhea, herpes, etc. Infection with trichomoniasis makes the individual at higher risk of getting HIV, herpes, and other sexually transmitted infections. Also, it has been associated with complications in pregnancy including low birth weight.
There is a public health concern to treat all infected individuals and partners in order to cure them and to contain the infection from spreading.
How can it be prevented?
The only prevention is abstinence. But practicing safe sex by using a latex condom will help to minimize the risk of getting sexually transmitted diseases. Also, limiting the number of sexual partners can decrease the chances of transmission as well. Another important point is encouraging partners to discuss infections and risks prior to engaging in sexual activity.