This document provides a classification and overview of intestinal protozoa including Entamoeba, Giardia, Dientamoeba, Trichomonas, and Balantidium. It describes the morphology, life cycles, pathogenicity and clinical manifestations of Entamoeba histolytica, the causative agent of amebiasis. Laboratory diagnosis and treatment options for intestinal amebiasis and extraintestinal complications like hepatic amebiasis are also summarized. The document briefly mentions other non-pathogenic intestinal amoebae including Entamoeba coli, Entamoeba dispar, Entamoeba hartmanni, Entamoeba gingivalis, Endolimax n
6. Entamoeba histolytica :
It was first described in 1875 by Fedor Losch
from Russia and named by Frits Scaudinn in 1903.
Epidemiology :
- Prevalence is close to 1-5% worldwide. Most
common in tropical countries, especially in areas with
poor sanitation. Also widely prevalent among
homosexuals.
- Third most common parasitic cause of death in
the world.
7. -Approximately 50 million cases and 110,000
deaths are reported by WHO annually.
Distribution :
The organism is acquired by ingestion of cyst
that differentiated into trophozoite in the ileum
but tends to colonize the ceacum and colon.
8. Morphology :
Has three stages : 1. Trophozoite
2. Precyst
3. Cyst.
Trophozoite :
1. Anaerobic parasite ; invasive form as well as the
feeding and replication form found in the feces
of patients with active disease.
2. size : vary from about 12-60μm in diameter.
10. - divided into clear glass like ectoplasm and
granular endoplasm.
- phagocytic stomata : endocytic food cups,
present on the surface and used in engulfment.
- freshly ingested erythrocytes : appear as pale
greenish, refractile bodies.
- pseudopodia : cytoplasmic protrution,
characteristically hyaline when first formed.
- lack of mitochondria, ER, golgi apparatus
11. - identification : 1. when stained with
hematoxylin : grayish and erythrocytes are
progressively paler.
2. when stained with
trichrome : typically green and cherry- red or
green erythrocyte.
12. 4. Nucleus :
- single, spherical.
- size : 4-6μm.
- karyosome : a small mass of chromatin in the
center.
- peripheral chromatin : a layer of granule on the
inner surface of nuclear membrane.
- between karyosome and peripheral chromatin
there is a faintly stained fibrils of the linin network
(cart wheel appearance).
- nuclear membrane : delicate and distinct.
13. -identification :
1. when stained with hematoxylin : intense
bluish black.
2. when stained with trichrome : dark red.
14. Precyst :
1. smaller to trophozoite but larger to cyst (
10-20μm).
2. oval with a blunt pseudopodia.
3. food vacuoles and RBCs disappear.
4. single rounded nucleus, absence of
ingested materials and lack of a cyst wall.
15.
16. Cyst :
1. presence of hyaline cyst wall which
appears highly refractile when unstained.
2. shape and size : spherical, sometimes
ovoid or irregular; vary from 10-20μm in
diameter.
3. Nucleus :
- 1-4 or rarely more.
- peripheral chromosome :
peripheral chromatin ring may appear
thicker and less uniform, may form thin
plaque on nuclear membrane or may
massed in crecent fashion at one side of
nuclear membrane.
17. - karyosome : eccentric.
- identification : when stained, nuclear
structure is similar to that of trophozoite.
4. Cytoplasm :
- Chromatoidal bars : rod shaped with
rounded/squared ends; large number in
mononucleated cyst surrounding a glycogen
vacuole.
18. - identification :
1. with iodine : light yellowish green to yellow
brown; chromatoidal bars do not stain; glycogen
valuole is dark yellow brown.
2. with heamatoxylin : chromatoidal bars are
bluish black;
3. with trichrome : chromatoidal bars are bright
red.
21. Symptoms and Pathogenesis :
Pathogenesis :
Intestinal ameobiasis :
Infective form : cyst.
Incubation period : 4-5days.
Virulances of E. histolytica include :
1. contact dependent cell killing : receptor
mediated adherence to target cell : by amoebic lectin
antigen ( GAL/GALNAG lectin).
22. 2. amoebic cytolysis of target cell : the production
of enzymes or other cytotoxic substances :
histolysin, amoebapain, cathepsin B protease.
3. others : amoebapore, hydrolytic enzymes
(RNAase, neutral protease, phosphatse).
23. Genesis:
Acute:
Liberation of metacystic trophozoite after exystation
Enter the crypts of Lieberkünn
Penetrate directly through the columner epithelium of the
mucous membrane with the help of amoeboid movement
and proleolytic enzymes.
Continuous lysis of tissues till they reach submucous coat.
Begin to pass in various direction dissolving surrounding
tissues.
Ultimately, destroy considerable area of submucosa.
24.
25. Chronic:
1. Small ulcers : involving only mucosa.
2. Extensive superficial ulcers with hyperaemia.
3. Thickening, fibrosis, stricture formation with
scarring of intestinal wall.
4. Extensive adhesion with surrounding viscera.
5. Diffuse pseudotumour like mass of granulation
tissue formation (Amoeboma).
26. Hepatic Amoebiasis:
Infective form : Trophozoite.
Occurs : 1-3 months of intestinal amoebiasis.
Common site : post.-sup. surface of rt. lobe.
Genesis :
Trophozoites are carried as emboli from the base of the
amoebic ulcer at caecum and ascending colon by
radicles of portal veins.
Capillary system acts as efficient filter and holds these
parasites.
Multiply there occluding hepatic venules.
Anoxic necrosis of hepatocytes
27. Inflammatory response surrounding hepatocytes leads to
abcess formation with the help of cytolytic action
which liquefies the solid slough .
Anchovy sauce pus :
liver abcess pus is thick;
chocholate brown in colour;
acidic and pH 5.2-6.7;
comprised of necrotic hepatocytes, without any
pus cell and and trophozoite.
28. Symptoms :
Clinical classification (WHO report on Amebiasis,1969) :
1. Asymptomatic.
2. Symptomatic :
A. Intestinal Amebiasis : i) Dysenteric
ii) Nondysenteric colitis.
B. Extraintestinal : i) Hepatic – a) acute
nonsuppurative.
b) liver abcess.
ii) Pulmonary
iii) others.
29. Clinical menifestations of Intestinal Amebiasis :
i) Asymptomatic :
- vague and nonspecific abdominal symptoms.
ii) Symptomatic :
a) Dysenteric :
- bloody diarrhoea with mucous and pus cell.
- abdominal pain, cramping, flatulance,
anorexia, wt. loss, chronic fatigue.
b) Nondysenteric :
- amoebic appendicitis : acute right lower
abdominal pain.
30. - Amoeboma : palpable abdominal mass.
- Fulminant colitis : intense colicky pain, rectal
tenesmus, >20 motions/day, fever, nausea, anorexia,
hypotention.
Clinical menifestation of Extraintertinal amebiasis :
i) Hepatic :
a) Acute non suppurative :
- liver tenderness and enlargement.
- fever, wt. loss, cough (with an evidence of
pneumonitis, involving right lower lung field.
31. b) Liver abcess :
- severe and continuous hepatic pain which may
reffered to right or left shoulder.
- hepatomegaly.
- fever.
Clinical menifestation of Pulmonary Amebiasis :
- pleurisy, with or without effusion or pleural rub.
- pneumonia.
- lung abcess.
32. Others :
- Amoebic infection of Skin : cutaneous amebiasis
of the face results in loss of vision of one eye, without
involving the mucocutanous surface.
- Vaginal, urethral, clitoral infections have been
reported along with amebiasis of the penis as a
consequences of anal intercourse or partner with
vaginal amebiasis.
37. B. Amoebic liver abcess Diagnosis :
1. Microscopy : detect trophozoite.
2. Stool culture.
3. Antigen detection by ELISA.
4. Antibody detection by IFA,ELISA,CFT,CIEP.
5. Histopathology.
6. Molecular diagnosis : PCR.
7. Ultrasonography.
PAS stain of E. histolytica in pus
38. Prevention :
1. Breaking the chain of transmission.
2. treatment of asymptomatic person who passes
cysts in stool may reduce opportunities of disease
transmission.
Treatment :
1. Metronidazole and Tinidazole.
2. Fluid and electrolyte replacement.
3. Drainage of larger hepatic abcess. CT guided
Percutaneous catheter drainage is usefull both in
resistance cases and perforation.
39. Suggested drug regimen :
Infection Drug and dose
Asymptomatic intestinal
amebiasis
Metronidazole 750mg 3
times daily for 10 days
Or,
Tinidazole 50mg/kg qds for
3days.
Amoebic dysentry, liver
abcess, ameboma
Metronidazole 750mg
3times daily for 10 days
followed by luminal
therapy.
Or,
Tinidazole 2gm p.o. for
3days
41. Entamoeba Coli :
- Previously it is called non pathogenic amoeba
- But now it is called pathogenic amoeba.
- 3 forms : trophozoite, precyst, cyst.
- It causes: Abdominal pain, diarrhoea.
- identification : when stained-
1. trophozoite : nucleus with irregular clumps
of peripheral chromatin; large, irregular, eccentric
karyosome.
2. cyst : typical nuclear structure; splinter
shaped or irregular chromatoidals.
42. Trophozoite of Entamoeba Coli :
(iron hematoxylin stain)
Cysts of Entamoeba Coli :
(iodine mount)
44. Difference between Entamoeba histolytica & Entamoeba Coli
:Charecteristics Entamoeba histolytica Entamoeba Coli :
Trophozoite
1. Size 15-20μm 20-25μm
2. Motility Progressive,directional,with finger like
pseudopodia.
Not progressive; short, blunt
pseudopodium appear to func. more to
ingest food.
3. Cytoplasm Clearly differenciated ectoplasm and
endoplasm.
Not so.
4. Cytoplasmic inclusion RSC, leucocytes, tissue debris, bacteria. Do not contain RBC.
5. Nucleus Small center karyosome, thin nuclear
membrane, lined by fine chromatin
granules.
Large, irregular,eccentric karyosome,
thick nuclear membrane, lined by coarse
chromatin granule.
Precyst
10-20μm, oval,no food vacules, nucleus
same as trophozoiye.
20μm.
Cyst
1. Size 12-15μm 15-25μm
2. Number of nuclei 1-4 1-8
3. Chromosomal body Thick bars with rounded ends. Splinter/ribbon/threadlike with irregular
ends.
45. Entamoeba disper, Entamoeba moshkovskii :
- morphologically indistinguishable from
Entamoeba histolytica, except for presence of
ingested RBC in Entamoeba histolytica.
- usually colonizes in the large intestine but
does not invade intestinal mucosa.
- does not induce antibody production.
- not complement resistant.
- can be distinguished from by isoenzyme
analysis, molecular method and detection of lectin
antigen.
46. Difference between Entamoeba histolytica &
Entamoeba disper :
E.histolytica E.dispar
Microscopy Ingested RBC may be
seen within cytoplasm
of trophozoite and is
diagnostic
No RBC seen within
cytoplasm of trphozoite
In vitro culture Axenic(grows without
bacteria)
Xenic(requires bacteria
for growth in culture)
Co-agglutination Positive Negative
Complement resistance Positive Negative
Zymodemes(Isoenzym
e)
II I & III
47. Entamoeba hartmanni :
- small race varient of Entamoeba histolytica.
- trophozoite : 3- 12μm and cyst 4-10μm.
usually colonizes the large intestine.
Entamoeba gingivalis :
- small (10-15 μm )
- inhabit in mouth.
- only trophozoite form.
- large food vacuoles containing WBCs.
- recovered from : vaginal secretion , oral cavity, pt.
with pyorrhoea alveolaris.
48. Endolimax nana :
- resides in the large intestine of humans and other
animals.
- Trophozoite : 8-10μm, shows sluggish motility.
- Cyst : 6-8μm, 1-4 nuclei; cytoplasm doesn’t have
chromatoidal body or glycogen vacuole.
- nucleus (both trophozoite and cyst) : karyosome
eccentric and irregular from which several achromatic
strands extend to the nuclear membrane. There is no
peripheral chromatin.
49. Iodamoeba butschlii :
- Trophozoite : 12- 15μm; ectoplasm and
endoplasm are not differentiated; cytoplasm more
vacuolated.
- Cyst : 10-20μm; round to oval;
nucleus : central karyosome surrounded by
refractile chromatin granules (bull’s eye or basket
appearance). On permanent smear,
may appear to have a halo around
karyosome;
cytoplasm : large iodin
stained glycogen mass or iodophilic
body; no chromatoid body.
52. Small, free living, widely distributed in soil and
water which can cause opportunistic infections in
men. Only 4 have association with human disease:
1. Naegleria fowleri
2. Acanthamoeba
3. Balamuthia mandrillaris
4. Sappinia diploidea
53. Naegleria fowleri :
‘Brain eating amoeba’ – first described by
physician M. Fowleri and R. F. Carter in 1965.
Morphology :
Two forms : 1. Trophozoite.
2. Cyst.
Trophozoite :
1. size : 8- 15μm.
2. Two forms : amoeboid and flagellated.
54. 1. Amoeboid form :
- only recognizable form in human.
- slug shaped (limex form)and possesses lobopodia.
- granular cytoplasm with food vacuoles.
- nucleus with large nucleilus, central karyosome, no
peripheral chromatin, fine nuclear membrane.
- only replicating form, divides by binary fission.
2. Flagellated form :
- pear shaped; possesses two flagella at the broader
end.
- shows typical jerky or spinning movement.
55. Cyst :
1. size 7- 15μm.
2. surrounded by a thick, smooth double wall.
56. Life Cycle and Pathogenesis :
Infective form : amoeboid form.
Incubation period : 5-7days.
Mode of transmission :
man acquired infection by nasal contamination
during swimming in fresh hot water (pond, river,
lake, swimming pool) or from inhalation of particles
of decaying animal manure.
Genesis:
Amoeboid form invades nasal mucosa, cribriform plate,
resulting in significant necrosis and heamorrhage in
the nasal mucosa and olfactory bulbs.
Travels along the olfactory nerve to reach brain.
57. In the brain:
1. Direct ingestion of brain tissue and by producing
food cups or amoebostome into which the cytopathic
enzymes are liberated.
2. Contact dependent cytolysis mediated by hemolytic
proteins, cytolycins, phoshpholipase enzyme.
Gradually produces an acute suppurative
meningoencephalitis.
Later it becomes hemorrhagic and necrotic.
58.
59. Clinical feature :
Initially-
1. Change in taste and smell.
2. Headache,nausea, vomiting, high fever.
3. Signs of meningeal involvement : stiff neck, positive
kernig’s sign.
Secondary symptoms-
1. confusion, hallucination, lack of attention, atexia,
seizure.
60. Laboratory diagnosis :
1. CSF analysis .
2. Microscopy.
3. Culture on nonnutrient agar.
4. Isoenzyme analysis.
5. Molecular method : PCR
6. Imaging : CT scan, MRI shows
- mark obliteration of cistern,
- diffuse enhancement around midbrain,
subarachnoid space, over cerebrum.
62. Treatment:
1. Amphotericin B 1gm/kg/day.
2. Rifampicin, Azithromycin and also antifungallike
miconazole and vorickg/onazole found to be
effective.
63. Flagellates ( intestinal and Genital)
• Classification based on habitat :
Intestinal or genital flagellates Habitat
Giardia lamblia Duodenum and jejunum
Enteromonas hominis Large intestine
Retromonas intestinalis Large intestine
Chilomastix mesnili Cecum
Dientamoeba fragilis Cecum and colon
Trichomonas tenax Mouth (teeth and gum)
Pentatrichomonas hominis Ileocecal region
Trichomonas vaginalis Vagina and urethra
Blood and Somatic flagellets Habitat
Leishmenia Blood and tissue
Trypanosoma Blood and tissue
65. Giardia lamblia :
It was first observed by A. V. Leeuwenhoekin
1681. It was named after Dr. F. Lambl and Prof. A.
Giard.
Kingdom : Protozoa.
Subkingdom : Archezoa.
Phylum : Metamonada.
Class : Trepomonadea.
Order : Diplomonadida.
Genus : Giardia.
Species : Giardia lamblia.
66. Classification :
According to origin of the host –
1. G. lamblia – humans and other mammals.
2. G. muris – mice.
3. G. agilis – amphibians.
4. G. psittaci – birds.
5. G. microti – voles.
G. lamblia can further be differentiated into 7
genotypes – A to G, out of which, genotype A and B
usually infect humans.
67. Epidemiology :
- worldwide distribution, most common in tropics
and subtropics.
- causes both epidemic and endemic intestinal
disease.
- a common cause of ‘traveler’s dirrhoea’.
Distribution :
Duodenum and upper part of jejunum where they
live closely to mucosa.
69. Trophozoite :
1. size : 9-21μm long and 5-15μm wide.
2. shape : pear shaped when seen in surface view,
and laterally, sickle shaped.
3. motility : erratic, with a slow oscillation about
the axis ( falling leaf pattern).
4. bilaterally symmetrical.
5. Flagella :
- 4pairs : ant., lateral,
ventral, post.
6. sucking disc : modified form of ant. portion of
the ventral surface.
70. 7. median bodies : two curved rods,posterior to
sucking disc
8. axoneme : intracytoplasmic portion of flagella.
9. basal bodies/ blepharoplast : 4 pairs; axonemes arise
from here.
10. parabasal bodies : connected to basal bodies
through which axoneme passes.
11. nucleus :
spherical or ovoid;
large, central karyosome;
no peripheral chromatin.
71. Cyst :
1. Size : 8-14μm by 7-10μm.
2. Contains :
4 prominent nuclei;
remnant of axoneme;
basal and parabasal bodies;
4 median bodies;
twice the number of intracytoplasmic
flagellar structure seen in trophozoite (dispersed
in a ‘helter-skelter’ fashion).
74. Symptoms :
A. Asymptomatic.
B. Acute giardiasis : incubation period – 1week to 3
weeks.
1. mild diarrhoea, flatulence, anorexia, crampy
abdominal pain, epigastric tenderness.
2. steatorrhoea and full blown malabsorbtion.
3. in severe cases : production of copious light
coloued , fatty stool.
hypoproteinemia
hypogamaglobulinemia.
folic acid and fat soluble vit.
deficiency.
75. C. Chronic cases :
1. foul smelling diarrhoea.
2. wt. loss.
3. growth retardation.
4. extraintestinal menifestation :
urticaria, ant. uveitis, salt and pepper
retinal change and arthritis.
76. Pathogenecity :
Infective dose : 10- 20 cysts.
Mode of transmission : feco-oral route, sexual
transmission in case of homosexuals.
Risk factors :
- Children who attend day care centers, including
diaper-aged children
- Child care workers, parents of infected children,
- People who swallow water from contaminated
sources.
- Swimmers who swallow water while swimming
in lakes, rivers, ponds and streams.
- immunodeficiency – IgA deficiency.
77. Pathogenesis :
Ingestion of cyst
Within 30 minutes, exystation occurs- two trophozoits
are released from each cyst.
Longitudinal binary fission in duodenum.
Adhere to duodenal mucosa – with the help of bilobed
adhesive disc (microtubules of median bodies,
contractile proteins, lentins) it adheres with intestinal
receptors (sugar molecules).
78.
79. A. Disruption of the intestinal epithelial brush border
(shortening and blunting of the villi, reduction in height
of the columner epithelial cells of mucosa), thus change
in the architecture of the intestinal villi.
Increased permeability and malabsorbtion.
a) Malabsorbtion of fat due to-i) unconjugation of bile
salt, ii) use of bile salt as growth factor, iii) decrease the
activity of pancreatic lipase- steatorrhea.
b) Disaccharidase deficiencies (lactate, xylose)- lactose
intolerance.
c) Malabsobtion of vit. B12 and folic acid.
d) Hypoproteinemia – protein loosing enteropathy.
e) Vilous atrophy- carcinoma gut.
80. B. Elaboration of enterotoxin (cystein rich surface
protein 136)
Stimulate cytokines production
Inflammatory response
a) Increase permeability.
b) Hypermotility.
c) Hypersecretion.
Diarrhea.
81. Several pathogenic mech. :
- achlorohydria, relative deficiency in secretory IgA
in small intestine (epithelial brush border) predisposes
to giardiasis.
- mechanical irritation : hyperemia and inflammation
results in duodenitis.
- bacterial colonization of the jejunum potenciates the
damage and responsible for symptomatic
malabsorbtion.
- antigenic variation : variant surface protein (VSP)
helps in evasion of host immune system and resistance
to intestinal protease – results in chronic and recurrent
infection.
82. Protection :
1. Anti giardia IgA antibody in human milk protects
breast fed infants from giardiasis.
2. Killing of trophozoites by the lipase of milk is due
to the release of free fatty acid from milk
triglycerides by the action of bile salts.
3. Macrophage, isolated from intestinal peyer’s patches
were able to ingest trophozoites of Girdia in vitro,
suggesting their role in host defense in giardiasis.
85. 2. Entero test : to detect trophozoite in duodenal
sample.
3. Antigen detection in stool :
- ELISA,
- direct fluorescent antibody : using labeled
monoclonal antibody against cyst wall protein
antigen.
- rapid ICT (triage parasite panel).
87. 4. Antibody detection : ELISA, IFA.
5. Culture : axenic media, such as diamond’s media.
6. Molecular method : PCR or gene probe- detection of
Giardia nucleic acid.
7. Radiological finding : Barrium meal X-ray- increased
secretion and irregular thickening of small bowel
folds.
Giardiasis; arrow showing irregular
mucosal swelling,distorted
pattern,fragmentation of barrium
column.
88. Treatment :
1. Metronidazole : 250mg thrice daily for 5days.
2. Tinidazole : 2gm.
3. Nitazoxanide : 500mg twice daily for 3days.
4. Furazolidine : children.
5. Paromomycin : Pregnancy.
6. In pt.s with AIDS and hypogammaglobulinaemia
are refractory to treatment. Prolong therapy with
metronidazole (750mg thrice daily 21 days.)
89. Prevention :
1. Improved food and personal hygiene.
2. Boiling or filtering of potentially contaminated
water.
3. Treatment of asymptomatic carriers.
4. Breastfeeding of infants.
90. Dientamoeba fragilis :
It is classified as an amoeboflagellate as the
flagellum is internal.
Distribution :
- cosmopolitan in distribution with incidence
rate varies from 1.4-19%.
- higher incidence in children.
Morphology :
Trophozoite is the only stage.
92. Trophozoite :
1. size and shape : irregular; 7- 12μm.
2. Nucleus :
-binucleated form;
an extranuclear spindle
extends between the two nuclei.
- delicate nuclear membrane.
- no peripheral chromatin.
- at the center a large mass composed of 4-8 separate
chromatin granule.
3. Cytoplasm : vacuolated, may contain ingested debris.
4. Pseudopodia : hyaline, broad and leaflike in appearance with
serrated margins.
5. Motility : progressive.
94. Laboratory diagnosis :
1. Stool examination : fresh direct wet preparation
should be examined immediately or stained by
permanent stain (recommended stains- Fields’,
giemsa, iron hematoxylin stain.)
- high percentage of binucleated trophozoites;
nuclei without peripheral chromatin; 4-8 chromatin
granules in a central mass.
Trichrome stain
95. 2. Antigen detection in stool : IFA, EIA.
3. Antibody detection in serum : IFA.
Treatment :
1. Iodoquinol is effective.
2. Alternative : tetracycline, paromomycin,
metronidazole.
3. Symptomatic treatment is usually preffered, because
pathogenecity is not confirmed.
97. • Belongs to :
Class : Trichomonadea.
Order : Trichomonadida.
Family : Trichomonadidae.
• Three species infect humans :
1. Trichomonas vaginalis : pathogen, resides in genital
tract.
2. Pentatrichomonas hominis : nonpathogen, resided in
large intestine.
3. Trichomonas tenax : nonpathogen, resided in mouth.
99. Introduction :
• Most common parasitic cause of STDs.
• First observed by Donne in 1836 from the purulent
discharge of a female.
• Worldwide in distribution and accounts for 10% of
cases of vulvovaginitis.
• Females are more affected.
• Metabolism is similar to a primitive anaerobic
bacteria.
• They ferment CHO.
• Unable to utilize fatty acid, sterol, purines and
pyrimidines; hence depends on exogenous source.
100. Morphology :
They only possess trophozoite stage.
Trophozoite :
- Shape : pear/ pyriform shaped.
- Size : 7-23µm long, 5-15µm
wide.
- Habitat : resides in vagina, urethra of women; urethra,
seminal vesicle, prostate of men.
- Movement : characteristic jerky, non-directional
movement.
- Flagella : 4 anterior, 1 recurrent flagellum which
traverse as undulating membrane.
101. - Costa : a rod like structure on the surface of the
parasite on which the undulating membrane is
supported.
- Axostyle : runs down the middle of the trophozoite and
ends in the pointed end of the posterior pole.
- Nucleus : containing central
karyosome with evenly
distributed nuclear chromatin.
- Cytoplasm : contains a
number of siderophore
granules along the axosyle.
- Hydrogenosome : respiratory
genosome.
103. Pathogenicity :
Predisposing factors :
1. Metabolic enzymes : adhesins, proteolytic enzymes,
iron regulated proteins, erythrocyte binding protein.
They help in binding with vaginal epithelium.
2. Vaginal pH : >4.5 is favourable.
3. Hormonal levels : the greater the concentration of
vaginal estrogens the less severe the symptoms.
4. Coexisting vaginal flora.
5. Strain and relative concentration of the organisms
present in the vagina.
104. Pathogenesis :
Adherence to the vaginal epithelium by 4 trichomonad
surface proteins.
Kill target cells by direct contact without phagocytosis
(contact- dependent cytopathic effect)
Then produce cell- detaching factor
Sloughing of vaginal epithelial cells.
Diffuse or patchy hyperemic mucosa with bright red
punctate lesion with vaginal discharge.
105. Clinical feature :
A. Asymptomatic : 25-50%; may harbour and transmit the
infection.
B. Acute infection : vulvovaginitis
1. Profuse foul smelling, purulent discharge;
sometimes frothy (10%) and yellowish
green colour mixed with a number of
PMN leukocytes with burning, itching, chafing.
2. Colpitis macularis : strawberry appearance of
vaginal mucosa ( small punctate
hemorrhagic spots.)
3. Dysuria, lower abdominal pain.
106. 3. In male : frequently asymptomatic.
1. non- gonococcal urethritis, epididymitis, prostatitis,
penile ulceration.
2. Thin discharge, dysuria, nocturia.
3. Enlarge and tender prostate.
C. Chronic infection : disease is mild with pruritus, pain
during coitus; scanty vaginal discharge mixed with
mucus.
107. D. Complication :
1. pyosalpinx, endometriosis, infertility, low birth
weight, cervical errosions.
2. it acts as a cofactor in amplifying HIV; it may
increase the transmission by approximately twofold.
3. Conjunctivitis and respiratory disease in infants.
108. Laboratory diagnosis :
A. Direct microscopy :
Sample : vaginal, urethral discharge, urine sediment,
prostatic secretions.
1. Wet (saline) mounting : demonstrate jerky motile
trophozoites and pus cell.
2. Permanent stain : Giemsa stain and papanicolaou
stain demostrate the morphology of trophozoite.
Trophozoite in
Giemsa stain
109. 3. Acridine orange fluorescent stain : rapid and sensitive.
4. Direct fluorescent antibody test (DFA) : trophozoite is
detected by staining with fluorescent labeled monoclonal
antibody.
Brick red trophozoite with
yellow banana shaped nucleus
Thin arrow- pus cell; curved
arrow- trophozoite in DFA
110. B. Culture : gold standerd. 95% sensitive and 100%
specific.
Specimen : should be collected properly and processed
immediately (bedside).
Incubation : for 3-7 days at 35-37˚C in microaerophilic
or anaerobic environment; followed by mounting of the
culture to demonstrate trophozoite.
Culture medias :
1. Lashe’s cysteine hydrosylate serum media.
2. Diamond’s trypticase yeast maltose media.
3. Cystein peptone liver maltose media.
4. Cell line like McCoy celll line : highly sensitive, can
detect as low as 3 trophozoite/ml.
111. ** InPouch TV : contains a specimen transport
container, growth chamber for incubation, slide for
mounting.
C. Antigen detection in vaginal secretion : indicates
recent infection.
1. Rapid ICT (dipstick test) : within 10 minutes; 83%
sensitive, 99% specific.
2. ELISA : using monoclonal antibody; 89% sensitive,
97% specific.
112. D. Antibody detection : ELISA- detect antitrichomonal
antibodies in serum and vaginal secretion.
E. Molecular method : PCR- detect T. vaginalis specific
β-tubulin genes.
** PCR based ELISA- for urine sample.
F. Transcription- mediated amplification test : urine and
genital specimen for men and women.
G. Others : 1. vaginal pH >4.5.
2. whiff test : positive.
113. Treatment :
1. Metronidazole & Tinidazole : 2g, single dose. Both
sexual partners must be treated simulteously to
prevent reinfection, specially asymptomatic males.
2. Resistance to metronidazole : it is relative and can
be overcome by higher dose of oral metronidazole.
Prevention :
1. Treatment of both partner.
2. Safe sex practice.
3. Avoidance of sex with infected persons.
4. Vaccine : trials are going on targeting potential
immunogenic antigens like 100kDa protein.
114. Trichomonas tenax
• Also called Trichomonas buccalis.
• Habitat : mouth, in gums and tartar of the teeth. Occurs
most frequently in pyorrheal pockets and tonsillar crypts.
• Morphology : smaller and more slender; 5-12µm long and
5-10µm wide.
• A harmless commensal; but if aspirated, transitory
bronchial or pulmonary infection, pulmonary abscess
occurs.
• Prevalence may vary from 0-0.25%, depending on oral
hygiene.
• Treatment is directed at the underlying conditions.
115. Pentatrichomonas hominis
• Worldwide distribution found both in warm and
temperate climates.
• Habitat : harmless commensal in large intestine.
• Morphology : pyriform; 5-15µm long and 7-10µm.
Undulating membrane is extended throughout the
body.
