4-Trichomonas

Trichomonas vaginalis
Geographical distribution: World wide
* Common sexually transmitted protozoon.
* Common at the age of 16-35 (sexually active period)
* More pathogenic in women than men
*T. vaginalis is concomitant with other pathogenic organisms.
NOTE:
1- Suitable pH for the parasite is 4.5 – 6 (low acidic).
2- Rare among young girls / menopause women - parasite requires estrogenized
epithelium for survival.
3- High in population at high risk for other venereal diseases & poor feminine
hygiene.
NOTE: Normal acidity is due to the action of Doderlein bacillus on glycogen content
of vaginal epithelial cells producing lactic acid.
NOTE:
Genus Trichomonas has 3 distinct species:
1- T. hominis which inhabit large intestine & non pathogenic.
2- T. tenax which inhabit oral cavity & commensals.
3- T. vaginalis is the Urogenital pathogenic flagellate

Morphology of Trophozoite stage:
* Average size 10-15 X 8 µ
* Pear shaped
Trichomonas vaginalis
•Single vesicular Nucleus anteriorly & a small
antero-lateral cytostome.
*Thin axostyle midway crossed by thick parabasal
body
* Four anterior free flagella and a lateral marginal
flagellum with an undulating membrane that reach
to about half of the body length.
No Cyst stage

Urogenital flagellate: Trichomonas vaginalis
Causes : Trichomoniasis
Geog. Distribution : worldwide
Habitat: T. vaginalis trophozoite lives:
In the vagina and urethra
of infected females.
In the urethra and prostate
of infected males
axostyle
flagella
Nucleus
15 X 8µ
(Never becomes cyst)
Trophozoite stage
Is the infective stage
Transmitted directly during sexual intercourse from
infected partner to the other.

In women
Pathogenesis and Clinical picture
Trophozoites feed on mucosal surface
of vagina and urethra producing
sloughing of squamous epithelial cells
Asymptomatic (50%)
Profuse odourous (foul-smelling) discharge, burning, itching,
dyspareunia, frequency of urination and dysuria.
(Painful sexual intercourse)
On examination:
vagina
Excessive discharge, diffuse vulval erythema
Vaginal wall inflammation (Strawberry cervix)

Pathogenesis and Clinical picture
In men
Infection is frequently asymptomatic
Symptoms appear when infection involves
prostate or higher part of uro-genital tract.
Symptoms include
Thin discharge,
dysuria
nocturia
Difficulty in urination
Urination by night
On examination
Enlarged tender prostate
and epididymitis
urethra
prostate
epididymus

Diagnosis
‣ Microscopic examination of wet film from discharge
‣ Culture of discharge. (modified Diamond’s media)
‣ Detection of T.vaginalis antigen in discharge by:
Enzyme immunoassay.
Direct fluorescent antibody test.
‣ Detection of DNA of the parasite by Molecular
techniques

Treatment
Metronidazole + Vinegar vaginal douche
Treatment of sexual partner simultaneously
Epidemiology and Control
Most common between humans at the age of 16-35
High incidence in ladies with deficient feminine hygiene
Treatment of the patient and the sexual partner
simultaneously
Diagnosis and treatment of asymptomatic males
Use of condoms to prevent infection

MCQ
The trophozoite is the infective stage in:
a- Giardia lamblia c- Trichomonas vaginalis
b- Entamoeba histolytica d- Balantidium coli
The protozoan parasite without a cyst stage is:
a- Entamoeba histolyica c- Balantidium coli
b- Giardia lamblia d- Trichomonas vaginalis