2. TRICHOMONAS
Genus Trichomonas shows the following important
characteristics:
I.An anterior tuft of flagellae,
II.Undulating membrane,
III.An axostyle,
IV. Only trophozoite stage.
Trichomonas is the simplest of all the protozoan
parasites because it has only trophozoite stage.
Trichomonas infects the urogenital tract unlike other
members of the order Trichomonadida which inhabit
the intestinal tract.
3. HUMAN TRICHOMONADS
Trichomonads occurring in humans belong to 3
species :
Trichomonas. vaginalis, Trichomonas.tenax &
Pentatrichomonas.hominis (Trichomonas.hominis ).
These species are highly site specific and typically
morphologically similar to each other.
Trichomonas.tenax is non pathogenic & inhabits the
oral cavity. It is found in the pyorrhoeic dental sockets
and around the tartar of the teeth.
Pentatrichomonas.hominis (Trichomonas.hominis ) is
non-pathogenic & inhabits the Illeocaecal region.
5. INTRODUCTION
Sexually transmitted infection,known as Trichomoniasis.
Discovered in 1836
Donne first observed the flagellate in 1837.
7.4 million cases reported every year
180 million people infected worldwide
Resides in genitourinary tract of males and females
50% asymptomatic carriers
HABITAT:
T.vaginalis trophozoite inhabits the vagina in female, the
prostate & seminal vesicles in males and urethra in both
sexes.
6. Trichomonas. vaginalis
Facultative anaerobic parasite
It produces energy by fermentation of sugars in a
structure called Hydrogenosome---A modified
mitochondria in which enzyme of oxidative
phosphorylation is replaced by enzyme of anaerobic
fermentation.
7. MORPHOLOGY
Trichomonas vaginalis belongs to Phylum Metamonada
Class: Parabasalia,
Order:
Trichomonadida
Family:
Trichomonadidae.
Genus : Trichomonas.
Trichomonas vaginalis is a flagellated protozoan
Trophozoite is the only stage present in the life cycle
Infective stage of the parasite. No cystic stage.
It is 7-30 µm long by 5-10µm wide It can survive outside
the body at temp as low as 15 0 C for up to 48 hours.
Trophozoite is pear shaped & shows “TWITCHING
8. MORPHOLOGY CONTD
There are 4 anterior free flagella, arising from shallow
depression, called periflagellar canal in the anterior
end of the body.
Fifth flagellum curves back along the margin of the
undulating membrane & is called Recurrent
flagellum. It lies in the shallow groove in the free
margin of the undulating membrane.
Just beneath the undulating membrane, a rigid
filamentous cord called COSTA is present.
Costa is believed to support the undulating membrane.
It has a median Axostyle which is a hyaline rod like
structure that runs throughout the entire length &
comes out through the posterior end.
Cytoplasm contains a large number of siderophilic
granules.
9. EPIDEMIOLOGY
Prevalence :Most common cause of vaginitis world
wide It is cosmopolitan in distribution, however
prevalence is not uniform because of sanitary and
hygiene habits 20-40% in Women 10% in Men.
Infected women harboring T.vaginalis in the genital
tract---is the chief reservoir.
Infected man is the carrier.
Main source is vaginal discharge containing
T.vaginalis.
T.vaginalis infection is seen in all age groups.
T.vaginalis infection is seen in both men &women.
10. EPIDEMIOLOGY
High incidence of symptomatic infection occurs in
women because of following reasons:
1.Natural flora (bacteria) keep the pH of the vagina
at 4-4.5 and ordinarily this discourages infections
.T. vaginalis can survive at a low pH .Once
established it causes a shift towards alkalinity (pH
5-6) which further encourages its growth.
2.Presence of zinc & inhibitory substances in the
prostatic secretions is harmful to T.vaginalis.
Trichomoniasis has been implicated as a
cofactor in the transmission of HIV.
12. LIFE CYCLE
Life cycle of T.vaginalis is simple & it is completed in
a single host either male/ Female.
In the females, parasite gets the nourishment from 1.
vaginal mucosa,2. ingested bacteria 3. RBC.
It reproduces by longitudinal binary fission.
Division of nucleus Division of
neuromuscular apparatus Separation of
cytoplasm into 2 daughter trophozoites.
Trophozoites are the infective stages
On sexual contact, trophozoites are transmitted to
male & gets localized in urethra and prostate gland
Replicates in the same way.
13.
14. CAUSES OF VAGINITIS
Three main types of vaginitis
Bacterial vaginosis About 50% of vaginitis cases -
Gardnerella or a mixed anaerobes
Trichomoniasis About 20% vaginitis cases-
Trichomonas vaginalis
Candidiasis About 25% of vaginitis cases C.
albicans (80-92%)
15. PATHOGENESIS & PATHOLOGY
It is not an invasive parasite.
It remains adherent to the squamous epithelium but
not columnar epithelium.
VIRULENCE FACTORS:
Protein liquids & proteases –help in adherence.
Lactic acid and Acetic acid- which lowers the vaginal
ph low ph is cytotoxic to vaginal epithelial cells.
Enzyme Cysteine proteases CP39-- Responsible for
hemolytic activity of the parasite.
PATHOLOGY:
Intracellular edema and “ chicken like epithelium” is
the most characteristic feature.
16. Biological Mechanism
Adhesion proteins
on surface of flagella
Ligand/Receptor
Cytoadherence -11-
23 different CP’s
(cysteine
proteinases)
CP’s play an
important role in the
pathogenicity of the
parasite.
17. Characteristics of CP39
The characteristics of CP39 are:
It is present in vaginal secretions in patients
with trichomoniasis
Its optimal temperature is 37˚C and a pH range
of 3.6 to 7.0
Suggested to be involved in tissue damage.
Has broad substrate specificity
Plays a role in parasite survival and immune
evasion by degrading hemoglobin and
immunoglobulins.
Indicative that CP39 plays a role in trichomonal
infection
18. SIGNS & SYMPTOMS
In females there is… urethritis, In males there is…
vaginitis&cervicitis. whitish discharge
inflammation of the vaginal although rare
canal pain and burning
vulvar itching leading to during urination .
edema
tenderness and chaffing
redness
yellow and green, foul
smelling discharge
painful urination-dysuria
pain during sex -dyspareunia
punctuate hemorrhages on
the cervix known as colpitis
macularis or strawberry
19. COMPLICATIONS
In women-PID is the most common & important
complication.
Pregnant women infected with T.vaginalis infection ---
likely to have
1.PROM 2. Premature birth 3. Pre-term/ Low birth
weight baby.
In men, common complications are prostatitis,
Epididymitis, Urethral stricture & Infertility.
21. SPECIMENS
In women : Vaginal discharge, Endocervical specimens.
Endocervical specimens are not used for wet mount
preparations, because of small number of parasites—
can collected for culture.
In men : 1.urethral discharge
2. prostatic fluid
3.Early morning first voided urine sediment.
4. Urethral swab before voiding urine
5. Semen.
Cultures of urethral scrapings/ urine are the most
effective method for diagnosis of the condition.
22. DIRECT DETECTION
MICROSCOPY—Saline Wet mount
Fixed smears are stained by 1.Acridine orange
staining.
2.Papinicolaou
staining.
3.Giemsa staining.
4.Leishman staining.
5.Direct Fluorescent
Antibody staining.
23. WET MOUNT
Specimen is collected by a swab from lateral
&anterior fornices of the vagina.
It is mixed with a drop of saline & a cover slip is
placed over it.
Microscopy shows :
T.vaginalis shows jerky & twitching motility.
PMN’S and Bacterial flora.
Sensitivity of wet mount prep with vaginal
secretion is 50-70%.
Amies gel agar transport medium can maintain
the viability for culture of T.vaginalis.
24. PERMANENT STAINING
1.Acridine orange staining—Rapid & accurate method.
2.Papinicolaou staining: Sensitivity is same as wet
mount
3.Giemsa staining.
4.Leishman staining.
5.Direct Fluorescent Antibody staining: It is more
sensitive than wet mount. Rapid method. Disadvantage
is the requirement of fluorescent microscope.
25. CULTURE
Culture is the gold standard.
It is the most sensitive method (>80%).
Specimens are inoculated immediately into appropriate
medium such as 1. Modified Diamond’s medium, 2.
Trichosel/ Hollander’s medium, 3. Trussel & Johnson
medium 4.Trypticase serum medium.
Cultures after inoculation are incubated aerobically.
In a positive culture, actively motile trophozoites are
demonstrated after 48 hrs of incubation at 37C.
New Culture systems (In pouch TV) and systems of
Empyrean diagnostics is commercially available which
allows direct inoculation,Transport, Culture &
Microscopy.
26. ANTIGEN DETECTION
1.ELISA—using Mab specific for a 65 KDa surface
polypeptide of T.vaginalis.
RAPID TESTS:
Latex Agglutination test
Immunofluorescent assay
Two immunochromatographic capillary flow assays are
commercially available-- 1.Osom Trichomonas Rapid
test
2.Xenostrip Tv Trichomonas vaginalis test
Serologic testing is NOT useful for diagnosis of
Trichomoniasis.
27. MOLECULAR DIAGNOSIS
A.DNA PROBES: These use synthetic oligonucleotide
probes for detection of Trichomonas vaginalis DNA in
vaginal secretions.
Affirm VPIII—is a direct DNA probe test & tests for the
3 most common syndromes associated with increased
vaginal discharge are:
Bacterial vaginosis (Gardenerella vaginalis)
Candidiasis (Candida.albicans)
Trichomoniasis (T.vaginalis).
Sensitivity of Affirm VPIII—is 90% and specificity is
98%.
B. Nucleic acid based amplification methods: PCR
& Transcription mediated amplification (TMA).
These amplification methods are not FDA cleared.
28. OTHER TESTS
DETERMINATION OF VAGINAL PH:
Vaginal ph is usually above 4.5 in Trichomoniasis/
Bacterial vaginosis But not in Candidiasis. Vaginal ph
is measured by Nitrazine paper method.
WHIFF TEST/ AMINE ODOR TEST:
This test is positive in Trichomoniasis/ Bacterial
vaginosis
In this test, vaginal swab is collected from the patient
and is mixed with 10% KOH for the presence of
polyamines.
In the presence of Trichomoniasis, a fishy odour is
released due to production of amines.
29. TREATMENT
. Treatment : Single dose of Metronidazole 2 gm
once, or Metronidazole PO 500 mg TDS for 7
days
For recurrent Trichomoniasis :Metronidazole x 7
days and Repeat, if still positive then give
Metronidazole 2 gm BD x5d Tinidazole or
Miconazole used if resistant Metronidazole is
contraindicated in the first trimester
Intravaginal Clotrimazole 100mg vaginal
suppository QID x7d Reinfection can happen
almost immediately
Treat the male sexual partner
Tinidazole is an alternate drug
30. PREVENTION
1.Personal hygiene
2. Barrier precautions
3.Avoidance of sexual contact with infected
partners.
4.Detection & Treatment of cases either
males/females.
NO VACCINE IS AVAILABLE.
