Pathogenic protozoa jana

INTESTINAL PROTOZOA

AMEBA

By Janan M. SalihMSc. 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


MORPHOLOGY

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


PATHOGENESISDepends 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 epitheliumFlask shapped ulcer Inestinal perforationAbdominal discomfortPassing soft stool Acute diarrhea (blood, pus and mucus)Abdominal painVomiting and feverMal 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

PATHOGENESIS AND CLINICAL 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 stage4.Diagnostic stage5.Drug of choice


CHECK FOR UNDERSTANDINGM.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



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



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 fissionEnter with

food

Pass in stool

Duodenal mucosa

Cyst

Trophozoite


Life Cycle of Giardia inside human body


PATHOGENESIS AND CLINICAL 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 UNDERSTANDINGState 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.


CiliatedCiliatedBalantidium coliBalantidium coli



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

Balantidium coliBalantidium coli


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



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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

Balantidium Balantidium colicoli


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


Health & Medicine

Pathogenic protozoa jana