Trichomonas infection, also called trichomoniasis, is a sexually transmitted disease of the urogenital system (relating to urinary and reproductive organs) of humans. It is caused one-celled parasitic microbes of the species Trichomonas vaginalis. The T. vaginalis parasite has a round body with four flagella (tail) that gives it a distinctive appearance that is easily identifiable under a microscope by medical professionals. The species, sometimes commonly called trich, is classified within the order Trichomonadida, and genus Trichomonas.
The World Health Organization (WHO) estimates that 180 million people around the world are infected annually with Trichomonas. The highest incidence of trichomoniasis occurs within sexually active women who have multiple partners. WHO and the U.S. Centers for Disease Control and Prevention (CDC) consider it to be the most common pathogenic (disease-causing) protozoan infection of humans in the industrialized world, with over 175 million infections annually occurring each year. The CDC Division of Parasitic Diseases (DPD) estimates that over eight million people become infected annually in North America. Trichomonas infection is considered a sexually transmitted disease or sexually transmitted infection (STD/STI).
Trichomonas infection is transmitted by sexual intercourse. It occurs more often in females than males. In females it is commonly found in the vagina, where it frequently causes burning and itching and an irritating discharge. It can also occur in the urinary tract, fallopian tubes, and pelvis of women. In males, it may occur in the prostate gland and urethra; and in both sexes it may irritate the bladder.
The parasite cannot survive in the human mouth or rectum or on dry objects such as toilet seats. It can live for up to 24 hours on moist surfaces such as bathing suits and hot tubs. However, such environments rarely contribute to transmission of the infection. It is, instead, almost always transmitted between humans through sexual intercourse or genital-to-genital contact.
Most symptoms do not show up until four to 28 days after being infected. General symptoms in women include abdominal soreness; discomfort with sexual intercourse; vaginal itching; oral lesions; vagina inflammation with gray, greenish-white, or greenish-yellow secretions that are often foul-smelling; labial swelling; vulvar itching; inner thigh itching; and the urge to urinate. Symptoms in pregnant females can often include preterm labor and birth of babies, low birth weight babies, and increased mortality of babies.
Other conditions more likely to occur are pneumonia, bronchitis, infertility, cervicitis (inflammation of the cervix), ectopic pregnancy, non-gonoccal urethritis (urethral inflammation), pelvic inflammatory disease, and reactive arthritis. Infected women are more likely to contract human immunodeficiency virus (HIV) infection and cervical cancer.
There are usually no symptoms in men. If symptoms occur they are usually described as itching of the genital area, burning feeling while urinating or ejaculating, and fluid discharge from urethra. In men, this infection stops on its own within several weeks. However, in rare cases men can develop epididymitis or prostatitis (inflammation of the epididymis or prostate).
Trichomoniasis occurs worldwide. Women between the ages of 16 to 35 years of age, according to the National Library of Medicine (NLM), of the National Institutes of Health (NIH), contract the disease more often than any other U.S. group. The frequency in the United States and Europe are similar, but its rate of incidence is much higher in Africa.
The infection can be diagnosed in women by studying fluid discharge from the vagina with a Pap smear. Such an examination under a microscope reveals the parasites causing the infection. In addition, a visual examination of the pelvis area will locate red blotches on the vaginal wall or cervix of infected women.
The infection is more difficult to diagnosis in men. More often than not, it is first diagnosed in their female sexual partner. However, men can be diagnosed through continued symptoms of burning or itching in the genital area even with treatment for Chlamydia or gonorrhea, two other sexually transmitted diseases. Specimens for examination under a microscope are often collected from the urethra (the tube that urine flows through).
Antibiotic medicines such as metronidazole are usually taken orally, intravenously, or as an intravaginal suppository gel. Sometimes tinidazole is given orally. Antibiotic medicines should be prescribed to the sexual partner, too.
The disease can be prevented either with total abstinence from sexual activities or can be minimized with the proper use of latex condoms during sex and with having a minimal number of sexual partners. The prognosis for Trichomonas infection is excellent if treated properly. Complications can happen, however, if proper treatment is not given in a timely basis. Extended infection in women can cause degradation in the tissues on the cervical surface.
Trichomonas infection is a sexually transmitted disease (often called STD, or SDI for sexually transmitted infection) that is normally not serious when antibiotics are used to treat the disease. However, its symptoms can be unpleasant, and an untreated infection can lead to pelvic inflammatory disease and resulting infertility. It causes an increased risk of contracting HIV. Although rare, pregnant women who are infected can give the infection to their baby during the delivery process.
Infection in young children can be an indication of sexual abuse. These children are treated for the infection and, if sexual abuse suspected, additional investigations are conducted.
WORDS TO KNOW
PATHOGEN: A disease causing agent, such as a bacteria, virus, fungus, etc.
PROTOZOA: Single-celled animal-like microscopic organisms that live by taking in food rather than making it by photosynthesis and must live in the presence of water. (Singular: protozoan.) Protozoa are a diverse group of single-celled organisms, with more than 50,000 different types represented. The vast majority are microscopic, many measuring less than 5 one-thousandth of an inch (or 0.005 millimeters), but some, such as the freshwater Spirostomun, may reach 0.17 inches (3 millimeters) in length, large enough to enable it to be seen with the naked eye.
SEXUALLY TRANSMITTED: Sexually transmitted diseases (STDs) and infections vary in their susceptibility to treatment, their signs and symptoms, and the consequences if they are left untreated. Some are caused by bacteria. These usually can be treated and cured. Others are caused by viruses and can typically be treated but not cured. More than 15 million new cases of STD are diagnosed annually in the United States.
Schwebke, J.R., and D. Burgess. “Trichomoniasis Is a Common Infection Whose Prevention Has Not Been a Priority.” Clinical Microbiology Review 17 (2004): 794–803.
Centers of Disease Control and Prevention. “Trichomonas.” <http://www.dpd.cdc.gov/dpdx/HTML/Trichomoniasis.htm> (accessed April 7, 2007).