Trichomoniasis is a sexually transmitted disease caused by Trichomonas vaginalis ( T. vaginalis ), a highly contagious protozoan. Over 70 percent% of patients acquire the infection after a single sexual contact. With bacterial vaginosis and candidiasis (yeast infection), T. vaginalis is one of the three leading causes of vaginal infection. T. vaginalis may also affect the urethra (the tube through which urine flows out of the body), or the prostate in men, but it is more common in women. About three million women in the U.S. are infected each year, with an estimated 13 percent% of U.S. women infected at any given time.
T. vaginalis, the protozoan that causes trichomoniasis, can only live within human beings. Furthermore, these microorganisms live specifically within the urethra and vagina in women and the urethra and prostate in men. Because live T. vaginalis have been found on wet towels used by infected women and in urine and semen specimens after several hours of exposure to air, non-sexual transmission is theoretically possible, though, extremely unlikely. Infection cannot occur unless the organisms come in direct contact with reproductive organs.
The symptoms of trichomoniasis vary from person to person. In fact, up to 50% of women who develop the infection (90% of infected men) have no symptoms at all. The most common symptom in women is a vaginal discharge, typically greenish-yellow and frothy, with small bubbles. Some women with this infection have a burning sensation when they urinate, pain during sexual intercourse, or abdominal discomfort. Patients with trichomoniasis may also notice redness, swelling, or even chafing around the vulva (the part of the body just external to the vagina). The severity of symptoms depends on the level of inflammation within the vagina.
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Whether an association between trichomoniasis, preterm labor, and low birthweight infants is truly causal or just a coincidence remains to be seen. Often, it is difficult for researchers to determine the patterns that cause disease. For example, years ago, many studies found an association between coffee and lung cancer-people who drank coffee were more likely to get lung cancer. Coffee drinking quickly became a public health concern. Later, it became evident that people who drank coffee were also more likely to smoke cigarettes. After patients who smoked cigarettes were removed from the study, coffee was no longer associated with lung cancer. Similarly, future studies will hopefully clarify the relationship between trichomoniasis and its effects on the pregnant woman and her baby.
In non-pregnant women, untreated trichomoniasis is considered a relatively minor condition. It usually remains a local infection, producing symptoms in the vagina and vulva. Rarely, does this infection spread to the uterus or fallopian tubes, as gonorrhea and chlamydia can. Nor, unlike syphilis or HIV, does trichomoniasis affect other organs of the body.
However, most sexually transmitted diseases (STDs) share the same risk factors. They include:
- beginning sexual activity at an early age;
- having multiple sex partners;
- having sex with someone who has had multiple sex partners; and
- using illicit drugs.done
As a result, patients infected by a sexual partner with T. vaginalis have likely been exposed to other sexually transmitted diseases. If you have trichomoniasis, your doctor will likely test you for other STDs, specifically chlamydia, gonorrhea, syphilis, and HIV.
In pregnant women, trichomoniasis can be serious. In a recent, large-scale study, pregnant women infected with T. vaginalis were 30% more likely than uninfected women to deliver preterm or underweight infants. In addition, infected women were 40% more likely to have an infant who was both preterm and of low birthweight. (Preterm childbirth is the leading cause of illness and death in newborn babies.) Despite these results, researchers are not sure whether trichomoniasis actually causes preterm labor or growth restriction.