Trichomonas vaginalis belongs to the protozoan family and is the causative agent of trichomoniasis. Women and men can become infected with trichomonas through unprotected sexual intercourse.
What is trichomonas vaginalis?
Trichomonas vaginalis is a parasite. This means that the small organism uses humans as hosts, feeds on them, and colonizes them for reproductive purposes. Trichomonas vaginalis is a so-called endoparasite because it resides in the organism of its host. The pathogen lives anaerobically. This means that it does not require an oxygen-free environment for its growth. Trichomonas vaginalis belongs to the protozoa. Protozoa are various unicellular, eukaryotic organisms that require substances built by other organisms for their metabolism. Within the protozoa there are different subgroups. Trichomonas vaginalis belongs to the group of flagellates. Flagellates have flagella with which they can move around. Other representatives of the flagellate group include Giardia lamblia, Leishmania, and trypanosomes.
Occurrence, distribution, and characteristics
Trichomonas vaginalis is distributed worldwide. Together with Toxoplasma gondii, the causative agent of toxoplasmosis, and Giardia lamblia, Trichomonas vaginalis is one of the three most common pathogenic protozoa in Central Europe. The surfaces of the mucous membranes in the urogenital tract are the main habitat of the protozoan. There are no stages that the pathogen occupies outside of humans. Thus, there are no limiting factors such as temperature or humidity in its spread. Transmission occurs directly during sexual intercourse from person to person. According to WHO estimates, up to 50 percent of the sexually active population in some countries is infected with Trichomonas vaginalis, depending on the standard of living and hygienic conditions. Within the urogenital tract, trichomonads feed on resident bacteria and cellular waste (detritus). The optimum pH for Trichomonas vaginalis is between 5.4 and 6.0, an environment found in the vaginal tract due to the presence of lactic acid bacteria. Trichomonas vaginalis thus feels particularly at home here. However, the protozoa do not tolerate dehydration. However, they can survive up to 24 hours in tap water. Transmission via bathing water, on the other hand, is not possible due to the low osmotic value. In swimming pools, the increased chlorine addition kills the pathogens within a very short time.
Diseases and complaints
Trichomonas vaginalis is the causative agent of trichomonosis. This is the most common STD worldwide and, unlike many other sexually transmitted diseases, is also common in central Europe. The worldwide incidence is between 19 and 47 percent. There are around 170 million new cases worldwide every year. In Europe, about 11 million new cases of trichomoniasis occur each year. Men are infected just as frequently as women. In women, the disease mainly manifests itself from puberty to menopause. The peak of the disease is between the ages of 20 and 30. This is due to increased sexual activity at this age. Risk groups include prostitutes as well as people with multiple sexual partners. According to estimates, up to 20 percent of the sexually active population in Europe is infected with Trichomonas vaginalis. The infections are favored by a changed environment in the vagina. These changes can be caused, for example, by pregnancy, the birth control pill or antibiotic administration. In the case of a trichomonad infection in women, the vagina and the cervix are particularly affected. As the disease progresses, 75 to 90 percent of patients also experience infestation of the urethra. The urinary bladder and the uterus, on the other hand, are rarely affected. In men, the trichomonads are mainly found under the foreskin, in the prostate or in the urethra. After an incubation period of about 10 days, women experience a strong urge to urinate, burning during urination, and severe itching in the genital area. Some patients suffer from pain during urination or bleeding after sexual intercourse due to mucosal irritation. The women’s vulva is very red and sore. A greenish-yellow, foul-smelling discharge is also typical of an infection with Trichomonas vaginalis. The typical strawberry cervix occurs in only two percent of all cases.This is characterized by numerous punctate, bloody lesions. If no therapy is given during this acute phase, the disease usually progresses to a chronic phase. Here, the symptoms of the acute phase are still present, but so faint that they are hardly noticed. In men, the infection often progresses completely without symptoms. In rare cases, a urinary tract infection or an inflammation of the prostate develops. Since men often do not show any symptoms, they often act as carriers because they are not aware of their disease. While trichomoniasis is not a life-threatening disease, it can be associated with serious complications. For example, it can cause rupture of the placenta during pregnancy. The risk of premature birth also increases with trichomonad infection. Furthermore, there seems to be an association between ovarian cancer and trichomoniasis. In very rare cases, fulminant trichomoniasis can result in sterility. If trichomoniasis is suspected, the physician will perform a smear test and examine it under the microscope. If infection with Trichomonas vaginalis is confirmed, the antibiotic metronidazole is the therapeutic of choice.
