Trichomonas spp.
There are 3 species of Trichomonads found in humans of which 2 are normally harmless commensals, T. hominis and T.tenax and one T. vaginalis which is a serious sexually transmitted pathogen.
Trichomonas vaginalis:
The only pathogenic spp. of genus trichomonas was discovered by Donne in 1836, in vaginal secretion. an anaerobic, parasitic flagellated protozoan, is the causative agent of trichomoniasis,
Morphology:
Trichomonas is a one-celled parasite that can live in the vagina, the cervix, or in the male lower genital tract. Under the microscope, this protozoan looks like a teardrop-shaped cell with a tail.. It is slightly larger than a white blood cell, measuring 9 X 7 ?m. Five flagella arise near the cytosome; four of these immediately extend outside the cell together, while the fifth flagellum wraps backwards along the surface of the organism. The functionality of the fifth flagellum is not known. In addition, a conspicuous barb-like axostyle projects opposite the four-flagella bundle; the axostyle may be used for attachment to surfaces and may also cause the tissue damage noted in trichomoniasis infections.
While T. vaginalis does not have a cyst form, organisms can survive for up to 24 hours in urine, semen, or even water samples. Combined with an ability to persist on fomites with a moist surface for 1 to 2 hours, T. vaginalis is among the most durable protozoan trophozites. Women with trichomonas usually have accompanying discharge or irritation.
Life Cycle:
T. vaginalis trophozoite reside on the mucosal surface of the vagina in infected woman. The growing trophozoite multiply by longitudinal binary fission and feed on local bacteria and leukocytes. T. vaginals trophozoite thrive in a slightly alkaline or slightly acid PH environment. The most common infection site of T. vaginalis in males is the prostate gland region and the epithelium of the urethra. The detailed life cycle in the male host is unknown.
Clinical features:
Approximately 20% of infected persons are asymptomatic carriers (asymptomatic cases most frequently in men ). The presenting complaint in female patients is usually a vaginal discharge, which often has a foul smelling , greenish-yellow liquid vaginal discharge . in moderate to severe cases, there may be complaints of local irritation or a burning and itching sensation in the vulva, vagina.
In addition, female patients may have urethritis, cystitis, cervicitis or infection of skenes ducts and bartholin gland. Ascending upper UTI , like pyelitis, is occasionally encountered trichomonal vulvovaginitis may lead to hematuria and nocturia. Vaginal examination usually reveals the so-called strawberry appearance due to marked congestion and hemorrhages in the vaginal mucosa.
Persistent urethritis or recurring urethritis are the conditions that symptomatic men experience as a result of T. vaginalis infection. Involvement of the seminal vesicles, higher parts of urogenital tract, and prostate may occur in sever cases of infection, these patients often release a thin , white urethral discharge that contains the T. vaginalis trophozoit.
T. vaginalis has been recovered from infants suffering from both respiratory infection and condunctivitis. These condition were mostly contracted as a results of trophozoits migrating from infected mother to her child through th birth canal and/ or during vaginal delivery .
Treatment:
Trichomonas is treated with an anti-protozoan antibiotic. The most effective treatment is metronidazole (Flagyl), which can be taken by mouth.
Trichomonas hominis
This flagellate is of cosmopolitan distribution. It is thought to be non-pathogenic although it has been associated with diarrhoeic stools. It is the most commonly found flagellate next to Giardia lamblia and Dientamoeba fragilis
Morphology.
T. hominis has no cystic stage. The trophozoite live in the cecal area of the large intestine and feed on bacteria, and not considered to be invasive measures from 5-15m in length by 7-10m in width. The shape is pyriform and has an axostyle which runs from the nucleus down the centre of the body and extends from the end of the body and undulating membrane which extends the entire length of the body and projects from the body like a free flagellum. It has 4 free flagella and a single nucleus at the anterior end.
Laboratory Diagnosis :
In a fresh stool, the flagellates move very rapidly in a jerky, non-directional manner. The axostyle and undulating membrane are diagnostic.
Trichomonas tenax :
Typical T. tenax trophozoite is oval to pear shaped , measuring
5 – 14 µm long .The single ovoid vesicular nucleus is filled with several chromatin granules and is usually located in the centre anterior portion of the organism .It has five flagella ( 4 anteriorly extended and one posterior ) An undulating membrane that expands (2/3) two thirds of the body length and its accompanying costa lypically lie next to the posterior flagellum . Thick axostyle runs along the entire body length . A small anterior cytosome is located next the axostyle opposite the undulating membrane.
There is no known cyste stage. although T. tenax is considered to be a harmless commensal in the month, there are report of respiratory infections and thoracic abscesses. The majority of cases diagnosis are based on the recovery of organisms from the teeth, gums or tonsillar crypts and no therapy is indicated.
T. tenax trophozoite survive in the body as mouth scavenger that feed primarily on local microorganisms located in tarter between the teeth , tonsillar crypts and gingival margin around the gums. T. tenax trophozoite multiply by longitudinal binary fission . T. tenax transmited by kissing, salivary droplets and fomites.
Laboratory Diagnosis:
The specimen of choice for diagnosing T. tenax trophozoite is mouth scavenger. Microscopic examination of tonsillar crypts and pyorrheal pockets of pyorrheal pockets of patients suffering from T. tenax infections often yields the typical trophozoites.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .