Trichomoniasis is a sexually transmitted disease (STD) caused by a tiny parasite. Also known as “trich” or “trick,” it infects both sexes but is more common in women. In the United States, about 5 to 10 percent of all women are infected with trichomoniasis, according to the National Women’s Health Resource Center. It is the most common nonviral STD.
Women can become infected with trichomoniasis through penis-to-vagina or vulva-to-vulva contact. Infection can also be spread through oral or anal sex or exposure to certain objects that are infested with the parasite. These objects include:
Damp towels and washcloths
Wet clothing, such as bathing suits
Toilet seats
Trichomoniasis does not usually pose a serious health threat. In many cases, a woman will not experience any symptoms of infection. However, in some cases the condition may cause discomfort. Trichomoniasis increases the risk of becoming infected with other STDs, including the human immunodeficiency virus (HIV), which can cause acquired immune deficiency syndrome (AIDS). In addition, trichomoniasis can result in complications for pregnant women, such as premature labor and delivery and low birth weight of the infant.
About trichomoniasis
Trichomoniasis is a sexually transmitted disease (STD) caused by a parasite that is passed from one person to another through sexual contact or through close contact with damp objects that contain the parasite. Also known as “trich” or “trick,” it infects both sexes, but is more common in women. It is the most common, curable STD in young women, and infects 7.4 million women and men every year, according to the U.S. Centers for Disease Control and Prevention (CDC).
In the United States, about 5 to 10 percent of all women are infected with trichomoniasis, according to the National Women’s Health Resource Center. In addition, some studies have found that up to 50 percent of women infected with other STDs also are infected with trichomoniasis. Rates are much higher for African-American women than for white and Hispanic/Latina women.
A single-celled protozoan parasite called Trichomonas vaginalis causes trichomoniasis.
Women can become infected through penis-to-vagina or vulva-to-vulva contact. Infection can also be spread through oral or anal sex. In addition, a woman can become infected if her genitals come into contact with certain objects that are infested with the parasite. These objects include:
Damp towels and washcloths
Wet clothing, such as bathing suits
Toilet seats
Trichomoniasis is considered one of the three main types of vaginitis. Many women with trich do not feel the symptoms of vaginitis (e.g., burning sensation, discomfort with urination).
Although people with trichomoniasis often experience no symptoms of infection, they can still pass the disease on to others. Trichomoniasis infection makes a person more vulnerable to other STDs, including the human immunodeficiency virus (HIV), which can cause acquired immune deficiency syndrome (AIDS). This is because infection with trichomoniasis stimulates the immune system, resulting in higher production of the immune response cells that the HIV virus targets. In addition, women who have both HIV and trichomoniasis are more likely to infect their partners with the HIV virus.
Pregnant women who are infected with trichomoniasis may experience premature rupture of membranes (PROM), premature labor and delivery, and may give birth to babies who have low birth weight (less than 5 pounds, 8 ounces, or 2,500 grams). For this reason, it is important for pregnant women to inform their obstetrician-gynecologist (ObGyn) if they are experiencing symptoms of the condition.
Signs and symptoms of trichomoniasis
About one-third to one-half of women infected with trichomoniasis experience no symptoms, according to the National Women’s Health Resource Center. However, some women do experience symptoms, usually between five and 28 days after exposure. These symptoms include:
Inflammation, irritation and itching in the genital area (vaginitis).
Yellow, green or gray vaginal discharge. This is often thick and foamy, and sometimes has a strong “fish-like” odor.
Discomfort during sexual intercourse (dyspareunia) or urination (dysuria).
Soreness or itching of the labia and inner thighs. The labia may also be swollen.
Lower abdominal pain (in rare cases).
Women who have any of these symptoms should notify their physician, preferably a gynecologist. The physician will do a pelvic exam and look for small, red sores in the vagina or on the cervix. Further testing will be needed to determine the exact cause of symptoms, which are similar to those of other inflammatory conditions of the vagina and cervix. Women should also refrain from having sexual relations until their condition is diagnosed and treated.
Women should be aware that a male partner infected with trichomoniasis usually has no symptoms. In some cases, men may have urethritis (inflammation of the urethra), dysuria or discharge from the penis. Even when untreated, a man’s symptoms may disappear after about a week or so, but he can still infect or reinfect his partner.
Diagnosis and treatment of trichomoniasis
In diagnosing trichomoniasis, a physician will compile a medical history and perform a complete physical examination, including a pelvic examination. During a pelvic examination, the physician will open the walls of the vagina and look for small red sores inside the vagina or on the cervix.
A sample of vaginal fluid will be obtained and examined under a microscope to determine the presence of parasites. Additional tests that may be performed include a vaginal culture or DNA test. Physicians frequently test for STDs (sexually transmitted diseases), such as gonorrhea and chlamydia, which often can accompany trichomoniasis.
In most cases, trichomoniasis is treated with a single oral dose of 2 grams of the prescription drug metronidazole. If this fails to cure the infection, a longer treatment regimen of three to five days may be required.
In 2004, the U.S. Food and Drug Administration (FDA) approved another drug, tinidazole, for treatment of trichomoniasis. This drug is now being used in patients who fail to respond to treatment with metronidazole.
Unlike some STDs, trichomoniasis has not developed strains that are resistant to medications, so the prognosis for patients who take these medications is excellent. In about 5 percent of cases, women do not respond to standard treatments. In such situations, an allergy to the medication may be to blame for the lack of success and a topical medicine called paromomycin may be prescribed.
The U.S. Centers for Disease Control and Prevention (CDC) recommends that both partners receive treatment if one partner has been diagnosed with trichomoniasis. This will ensure that any traces of the parasite in either partner are eliminated and will not be further transmitted. Patients also should refrain from sexual relations until they and their partners have completed treatment and are no longer exhibiting symptoms.
Women should not take these medications for this condition during the first three months of pregnancy, according to the FDA. However, after the first trimester, metronidazole or tinidazole may be taken if necessary. The National Women’s Health Information Center suggests treating pregnant women who have symptoms and not treating those who have no symptoms.
Individuals who are successfully treated for trichomoniasis can still become infected again in the future if they are exposed to the parasite.
Prevention methods for trichomoniasis
There is no medication in the United States that may help prevent trichomoniasis. However, a vaccine for trichomoniasis has been marketed in Europe but has proven to be largely ineffective. There are several factors that can reduce the chances of contracting trichomoniasis. These include:
Refrain from having sexual intercourse. Complete abstinence – refraining from vaginal, anal and oral sex – is the best way to prevent becoming infected with trichomoniasis.
Maintain a sexual relationship with just one partner. Restricting sexual relations to just one partner who is not infected with trichomoniasis can significantly reduce the risk of contracting the infection.
Use condoms. Use of condoms during vaginal, anal and oral sex can substantially reduce – but not eliminate – the risk of contracting trichomoniasis. Condoms must be used every time a person has sex. Male latex condoms or female polyurethane condoms should be used during vaginal sex. Male condoms should be used during anal sex, and a rubbery material known as a dental dam should be used during oral sex. It should be noted that although female condoms and dental dams offer some protection against sexually transmitted diseases, they are not as effective as male latex condoms.
Do not share swimsuits, towels, washcloths, bath sponges, loofahs or bath brushes. The trichomonosis parasite can live outside the body for as long as 45 minutes and can be transmitted to someone whose genitals come in contact with damp objects that have the parasite on them.
Exercise caution when using public restrooms, as trichomoniasis can be transmitted through contact with a toilet seat. Refrain from sitting on an unprotected toilet seat or use a protector before sitting on the seat.
Questions for your doctor about trichomoniasis
Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to trichomoniasis:
What is the most likely way I contracted trichomoniasis?
How do I know my symptoms are not caused by another condition?
How quickly will I know the results of my test?
What type of medication will be prescribed for my condition?
How long will I need the medication?
How will I know if I no longer have trichomoniasis?
When is it safe for me to resume having sex?
Am I at risk for other conditions with trichomoniasis?
Do past sexual partners need to be tested and treated for the disease as well as my current partner?
If I’ve been diagnosed with trichomoniasis, am I at higer risk for infection in the future?
