Pathogenic protozoa jana

INTESTINAL PROTOZOA
AMEBA
By
Janan M. Salih
MSc. Medical
Microbiology
Practical Parasitology- 3rd
class Medicine College 2015-2016 Janan M. Salih

-- The disease called (Amebiasis or
amebic dysentery)
-- Normal habitate in wall of large
intestine (caecum and upper
colon)
-- World-wide in distribution
-- It is endemic in Iraq
-- Invasive and pathogenic protozoa
-- Feco-oral transmission
1-Entamoeba histolytica

MORPHOLOG
Y
 Trophozoite, precyst, cyst
and metacyst.
 Trophozoite stage:
Irregular shape, clear
ectoplasm and granular
endoplasm, consist of one
nucleus with central
karyosome ,food vacuoles
containing R.B.Cs and the
organ of movement is a
pseudopodium.
There are 4 stages during life cycleThere are 4 stages during life cycle
Entamoeba histolytica

CYST STAGE
SPHERICAL IN SHAPE (INFECTIVE STAGE),
RESISTANT STAGE TO ADVERSE ENVIRONMENTAL
CONDITIONS.
CONSIST OF 4 NUCLEI AND CHROMATOIDAL
BODIES( CIGAR SHAPE )

 Mature cyst is infective stage
 Destruction of cyst wall
emerged of metacyst which is
converted to trophozoite. This
mechanism called excystation.
 Then converted to precyst and
cyst. This mechanism called
encystation.

LIFE CYCLE OF ENTAMOEBA INSIDE
HUMAN COLON
Mucosa of large intestine
In the
lumen
Quadrinucleate cyst
Enter with food
Pass out in stool
Precyst Uninucleate cyst Binucleate cyst
Binary fission
Attached
to mucosa
trophozoite
Lumen(non invasive) form

Life cycle of
E. histolytica

PATHOGENESIS
Depends on:
 Parasite virulence.
 Host resistance.
 Condition of the intestinal tract.
Non-pathogenic: in the lumen.
OR Pathogenic: trophozoites invade intestinal mucosa.
Trophozoites produce histolytic enzyme that produce necrosis of mucosa
leading to the formation of flask-
shaped ulcer.
Trophozoite

 Incubation period ( days—3 months )
 Necrosis of mucosal epithelium
 Flask shapped ulcer
 Inestinal perforation
 Abdominal discomfort
 Passing soft stool
 Acute diarrhea (blood, pus and mucus)
 Abdominal pain
 Vomiting and fever
 Mal nutrition
PATHOGENESIS AND CLINICAL
SIGNS

 Intestinal :-
a. Dysenteric ( symptomatic )
b. Non dysenteric ( asymptomatic )
 Extra intestinal :-
a. Superficial on the skin
b. Deep in the liver, heart, joints , lungs,
urogenital tract and brain
Note :- All extra intestinal amebiasis
are secondary except skin amebiasis
SIGNS

 Clinical signs
 Direct stool examination: Trophozoites are found in
diarrhoeic stool. Cysts are found in formed stool Concentration
method
 Rectal swab
 Intestinal biopsy
 serological tests like ELISA test
Diagnosis

The drug of choice
1. Metronidazole (flagyl)
2. Iodohydroxyquniline
3. Antibiotics (Tetracycline)
Treatment

 Avoid contamination of food and water
with cyst of Entamoeba histolytica
 Good personal hygiene
 Screening of food handlers
Prevention

Mention the folllowing for E.
histolytica:
1.Normal habitate:
2.Disease:
3.Infective stage
4.Diagnostic stage
5.Drug of choice

CHECK FOR UNDERSTANDING
M.C.Q.
1- Entamoeba histolytica trophozoites are found in:
a- Duodenum of infected human.
b- Jejunum of infected human.
c- Caecum of infected human.
d- All of the above.
2- Infection with Entamoeba histolytica occurs through
eating green salad contaminated with:
a- Trophozoites of Entamoeba histolytica.
b- Cysts of Entamoeba histolytica.
c- Both trophozoites and cysts of Entamoeba
histolytica.

3-PATHOGENICITY OF ENTAMOEBA HISTOLYTICA DEPENDS
ON:
a- Parasite virulence.
b- Host resistance.
c- Condition of intestinal tract.
d- All of the above.

STATE TRUE OR FALSE
 Cyst passers are the main source of Entamoeba
histolytica infection.
 Trophozoites of Entamoeba histolytica produce ulcers
with indurated margin in intestinal mucosa.
 Examination and treatment of food handlers is very
important to control Entamoeba histolytica infection.
 Infection with Entamoeba histolytica is totally
localized to the gastrointestinal tract.
 Both trophozoites and cysts of Entamoeba histolytica
are infective to man.
True
False
True
False
False

2- Blastocystis hominis
rd
By
Janan M. Salih
MSc. Medical Microbiology

 The normal habitate in the lower part of large intestine
 Pathogenic protozoa
 The trophozoite is diagnostic stage
 The cyst is infective stage
 Route of transmission by Fecal-oral
There are 3 forms: -
1. Granulated
2. Amebic
3. Vacuolated (most common in Iraq)
2. Blastocystis hominis

Biopsy Blastocystis Hominis (Trophozoite)

Morphology of vaculated form:
*The shape and size of troph. is variable .
The cytoplasm is compressed at the peripheral and consist
of 3-5 small nuclei.
*The clinical sings are :-
 Recurrent diarrhea
 Abdominal pain
 Abdominal gases
* There is no effective Drugs but Metronidazole with
Tetracycline or septrin may be effective.

(Flagellated )
1.Giardia lamblia
By
Janan M. Salih

 The disease called Giardiasis
 The normal habitat in the upper part of the
small intestine (Duodenum).
 Fecal-oral transmission, filth flies, direct
contact, cats, dogs and wild animals.
 Direct life cycle
 It is world wide in distribution
 It is endemic in Iraq
Giardia lamblia

MORPHOLOGY
 It has 2 stages:-
Trophozoite and cyst stages
The trophozoite (diagnostic stage):
 It is very active in movement (leaf-
failing), broadly rounded interiorly and
tapering posteriorly .
 Two large oval nuclei located in
adhesive discs, 4 pairs of flagella.
Giardia lamblia

Giardia lamblia (Trophozoite-tear drop shape)

MORPHOLOGY
 The cyst is oval in shape,
contains of 4 nuclei,
surrounding by thick hyaline
cyst wall and presence of
curved fibrils
 It is infective and diagnostic
stage
Giardia lamblia

Giardia lamblia (Cyst)

LIFE CYCLE OF GIARDIA INSIDE HUMAN
BODY
Binary fission
Enter with food
Pass in stool
Duodenal mucosa
Cyst
Trophozoite

Life Cycle of Giardia inside human body

SIGNS
 The parasite do not invade tissues
but forming pavement–like
membrane covering the mucosa
causing functional disorder and
prevent absorption of fats, some
vitamins and lead to mal absorption
 In acute cases the main symptoms
are:-
Fatty diarrhea, epigastric pain,
dehydration and loss of body
weight.
Giardia lamblia

 Clinical signs
 Direct examination of stool
 Concentration method
 Rectal swab
 Serological tests like ELISA test & EIA.
 Duodenal aspiration
 Intestinal biopsy
Giardia lamblia (Diagnosis)

TREATMENT AND PREVENTION
The drug of choice is Metronidazole
OR Tinidazole Recently Albendazole.
 The alternative drugs are quinacrine
and furazolidine
Control by
 Good personal hygiene
 Boiling of drinking water
 Treatment of food handlers

CHECK FOR UNDERSTANDING
State True or False
 G.lamblia infection is common in children.
 G.lamblia trophozoites are attached to caecal
mucosa.
G.lamblia trophozoites are attached to duodenal mucosa.
 Giardia infected patients complain of diarrhoea .
 Both trophozoites and cysts of Giardia are infective
to man.
T
F
T
FOnly Giardia cysts are infective to man.

CiliatedCiliated
Balantidium coliBalantidium coli
By
Janan M. Salih

 The disease is called balantidiasis or
balantidial dysentery.
 The normal habitat in the cecal region of the
large intestine of man and pigs.
 Mode of transmission fecal–oral.
by ingestion of contaminated food or water
(NOT in undercooked meat) with feces contain
the mature cyst
 It is found in non Islamic countries

Morphology
It has 2 stages:-
1.Trophozoite stage: is the largest intestinal protozoa
infected man.
 It is ovoid in shape. The anterior end is conical and the
posterior end is rounded.
 It consist of simple moth (cytostome) and simple anus
(cytopyge).
 It has 2 nuclei the large one is kidney shape called
macronucleus e and the small one is spherical shape called
micronucleus located in concavity of the macronucleus.
 It has 2 contractile vacuoles. Food vacuoles in the cytoplasm
contain debris,bacteria, RBCs, and fragments of host
epithelium
 The body surrounded by large number of short cilia.

Trophozoite
Conjugation Binary fission
Balantidium coli Trophozoite

Balantidium coli Trophozoite

2. Cyst stage: is spherical in shape
surrounded by cell wall
 Cilia are lost
 Macro and micronucleus are present
 It is infective stage

Cyst enters with food
trophozoite
Trophozoites multiply by both Transverse
binary fission & Conjugation
Attached
to mucosa
In the
lumen
Pass out in stool
Mucosa of large intestine
Life Cycle of Balantidium coli inside human colon

LIFE
CYCLE
Multiplication :- occur by two
method:
1- Asexual type by binary fission .
2- Sexual type by conjugation .

 The parasite penetrated the mucosa
and sub mucosa of the intestine caused ulceration.
 The main symptoms are:-
 Acute diarrhea (dysentry)
 Abdominal pain
 The disease is asymptomatic in carriers
Pathogenesis and Clinical Signs

 Clinical signs
 Direct examination of stool
 Pass in diarrhoeic stool Pass in formed stool
 Serological tests
 Intestinal biopsy
Balantidium coli diagnosisBalantidium coli diagnosis

The drug of choice Tetracyclines 500 mg four
times daily for 10 days and Metronidazole 500
mg three times daily for 5 days.
 Good personal hygiene
 Avoid exposure to animal (pigs) sources.
Treatment and Prevention

Pathogenic protozoa jana

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