Trichomoniasis
Trichomoniasis is a sexually transmitted disease of the vagina or urethra caused by Trichomonas vaginalis, a single-celled organism.
Trichomonas vaginalis commonly infects the genitals and urinary tract of men and women. However, women are more likely to develop symptoms. About 20% of women develop trichomoniasis of the vagina during their reproductive years.
In men, urethral infection with no or minimal symptoms is common, although rarely the epididymis and prostate are infected. In some populations, Trichomonas may account for 5 to 10% of all cases of nongonococcal urethritis.
Symptoms and Diagnosis
In women, the disease usually starts with a greenish yellow, frothy vaginal discharge. In some women the discharge is slight. The vulva may be irritated and sore, and sexual intercourse may be painful. In severe cases, the vulva and surrounding skin may be inflamed and the labia swollen. Pain on urination or frequency of urination, such as occurs in a bladder infection, may occur alone or with the other symptoms.
Men with trichomoniasis may have no symptoms but still infect their sex partners. Many men have nongonococcal urethritis with symptoms of discharge from the urethra, pain during urination, and a need to urinate frequently. The role of Trichomonas in prostate infections is unclear.
The organism is more difficult to detect in men than in women. In women, the diagnosis can usually be made quickly by seeing the organism in a sample of vaginal secretions under a microscope or after several days by culture. Tests for other STDs are usually performed as well, because Trichomonas is common in people with gonorrhea or chlamydia. In men, secretions from the end of the penis (obtained in the morning, before urination) may be examined under a microscope and sent to the laboratory for culture. Microscopic examination of the urine may also detect Trichomonas.
Treatment
A single dose of metronidazole taken by mouth cures up to 95% of infected women; however, they may become reinfected unless their sex partners are treated simultaneously. It is not known whether a single-dose treatment is effective in men, but men are usually cured after 7 days of treatment.
If taken with alcohol, metronidazole may cause nausea and flushing of the skin. The drug also may cause a metallic taste in the mouth, nausea, or a decrease in the number of white blood cells and, in women, an increased susceptibility to vaginal yeast infections (genital candidiasis). Metronidazole is best avoided during pregnancy, at least during the first 3 months. Infected people who have sexual intercourse before the infection is cured are likely to infect their partners.
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