الرحیم الرحمن الله بسم

الرحیم الرحمن الله الرحیم بسم الرحمن الله بسم

Entamoeba gingivalisEntamoeba gingivalis(non-pathogen)(non-pathogen)

--Prevalance ratePrevalance rate - Live site- Live site - Morphology- Morphology - - cytoplasm cytoplasm

DiagnosisDiagnosis: may be mistaken for E.histolytica from a pulmonary abscess: may be mistaken for E.histolytica from a pulmonary abscess

Entamoeba coliEntamoeba coli(non-pathogen)(non-pathogen)

Prevalance:Prevalance: 1 to 50%1 to 50%

MorphologyMorphology: : trophozoite range 15-50trophozoite range 15-50µmµm

( very closely resemble E.histolytica)( very closely resemble E.histolytica) - cytoplasm- cytoplasm - Pseudopodia- Pseudopodia MotilityMotility *nucleus*nucleus *karyosome*karyosome *peripheral chromatin*peripheral chromatin

Entamoeba hartmaniEntamoeba hartmani

*small race of E.histolytica (morphologic similarity)*small race of E.histolytica (morphologic similarity) *size: trophozoite < 12 *size: trophozoite < 12 mmμμ , , cc yst < 10 yst < 10 mmμμ

*only clear-cut distinction between the two species is size*only clear-cut distinction between the two species is size *trophozoite ingest bacteria but no RBC*trophozoite ingest bacteria but no RBC

Entamoeba dispareEntamoeba dispare : :*There is no morphologic differences between this amoeba with E.histolytica*There is no morphologic differences between this amoeba with E.histolytica*This amoeba no ingest RBC*This amoeba no ingest RBC

Iodamoeba butschliiIodamoeba butschlii : : **Trophozoite size(4-20Trophozoite size(4-20μμmm), cytoplasm may be contain bacteria, large karyosome, small ), cytoplasm may be contain bacteria, large karyosome, small granulesgranules

*Cyst size(9-10 *Cyst size(9-10 μμmm): contain glycogen vacuole, sigle nuclei

Endolimax nanaEndolimax nana

**most common of the smaller intestinal amaebamost common of the smaller intestinal amaeba *Size: trophpozoite and cyst is similar to theat of E.hartmani*Size: trophpozoite and cyst is similar to theat of E.hartmani *Motility: sluggish*Motility: sluggish pseudopodia extruded rapidly pseudopodia extruded rapidly *Cytoplasm:*Cytoplasm: Nucleus: contain large karyosomeNucleus: contain large karyosome *Cyst:*Cyst:

AmebiasisAmebiasis(Amebic Dysentery)(Amebic Dysentery)

Causal agentCausal agent: : Entamoeba histolyticaEntamoeba histolytica is well recognized is well recognized as a pathogenic amoeba.as a pathogenic amoeba.

Geographic DistributionGeographic Distribution: Worldwide, with higher : Worldwide, with higher incidence of amebiasis in developing countries. incidence of amebiasis in developing countries. 

In industrialized countries, risk groups include male In industrialized countries, risk groups include male homosexuals, travelers and recent immigrants, and homosexuals, travelers and recent immigrants, and institutionalized populations.institutionalized populations.

History: Loosh was first described in 1875

MorphologyMorphology Different form of E. histolytica; Different form of E. histolytica;

1- trophozoite 1- trophozoite

2- precyst2- precyst

3- cyst(1, 2, 4 nuclei)3- cyst(1, 2, 4 nuclei)

Trophozoite chractereTrophozoite chractere

SizeSize: : 12-6012-60μμm m in diameter in diameter; ;

Non-invasive form ( minuta) / E. dispareNon-invasive form ( minuta) / E. dispare Invasive form (magna) contain RBC, E. histolyticaInvasive form (magna) contain RBC, E. histolytica PseudopodiaPseudopodia: : quickly thrust out and vary in form; short, blunt, abroad, long, quickly thrust out and vary in form; short, blunt, abroad, long,

figerlikefigerlike MotilityMotility: actively motile , progressive , directional: actively motile , progressive , directional

EctoplasmEctoplasm: : is hyaline and distinguish from endoplasmis hyaline and distinguish from endoplasm

EndoplasmEndoplasm: : is granular and may be contain ingested is granular and may be contain ingested RBCRBC

NucleoplasmNucleoplasm: : contain a small centric or acentric karyosome with fine , uniform contain a small centric or acentric karyosome with fine , uniform granules of peripheral chromatingranules of peripheral chromatin

Non-invasive forminvasive form

Different form of E.histolytica cystDifferent form of E.histolytica cyst

Life cycleLife cycle

Life cycle

EpidemiologyEpidemiology

PrevalencePrevalence of amebic infection varies with level of sanitation of amebic infection varies with level of sanitation and generally higher in tropics and subtropics than in and generally higher in tropics and subtropics than in tempearate climates. tempearate climates.

*Worldwide prevalence is about 10% to 50%*Worldwide prevalence is about 10% to 50% **Cyst passersCyst passers are important source of infection are important source of infection

The true estimated prevalence of E. histolytica is close to 1% The true estimated prevalence of E. histolytica is close to 1% worldwide.worldwide.

Entamoeba histolyticaEntamoeba histolytica is the second leading cause of is the second leading cause of mortality due to parasitic disease in humans. (The first being mortality due to parasitic disease in humans. (The first being malaria). Amebiasis is the cause of an estimated malaria). Amebiasis is the cause of an estimated 50,000-50,000-100,000100,000 deaths each year. deaths each year.

Transmission methods of infectionsTransmission methods of infections

1-driect contact of person to person( fecal-oral)1-driect contact of person to person( fecal-oral)

2- Veneral transmission among homosexual 2- Veneral transmission among homosexual males( oral-analmales( oral-anal

3- Food or drink contaminated with feces containing the 3- Food or drink contaminated with feces containing the E.his. CystE.his. Cyst

4- Use of human feces (night soil) for soil fertilizer4- Use of human feces (night soil) for soil fertilizer

5- contamination of foodstuffs by flies, and possibly 5- contamination of foodstuffs by flies, and possibly cockroachescockroaches

PathogenesisPathogenesis

Effective factores:Effective factores: 1- strain virulence1- strain virulence: : - classic strain - classic strain - non-classic strain; Laredo , Huff, ….- non-classic strain; Laredo , Huff, …. - pathogen zymodemes- pathogen zymodemes

2- susceptibility of the host; nutrition status, immune-sys.2- susceptibility of the host; nutrition status, immune-sys. 3- breakdown of immunologic barrier (tissue invasion)3- breakdown of immunologic barrier (tissue invasion)

Pathogenicity mechanismsPathogenicity mechanisms 1- secreting proteolytic enzymes( histolysine ) 1- secreting proteolytic enzymes( histolysine )

and cytotoxic substances. and cytotoxic substances. 2 - contact-dependent cell killing2 - contact-dependent cell killing 3 – cytophagocytosis3 – cytophagocytosis

Amebic killing target cell: Amebic killing target cell:

1- receptore-mediated adherence of amebae to target cell ( adherence 1- receptore-mediated adherence of amebae to target cell ( adherence lectin)lectin)

2- amebic cytolysis of target cell 2- amebic cytolysis of target cell 3- amebic phagocytosis of killed target cell3- amebic phagocytosis of killed target cell

Clinical symptomsClinical symptoms Asymptomatic infection Symptomatic infectionAsymptomatic infection Symptomatic infection Intestinal Amebiasis Extraintestinal AmebiasisIntestinal Amebiasis Extraintestinal Amebiasis

Dysenteric Non-Dysenteric colitisDysenteric Non-Dysenteric colitis Hepatic Pulmonary The extra Hepatic Pulmonary The extra focifoci

Liver abscces Acut nonsupprativeLiver abscces Acut nonsupprative

Intestinal Amebiasis symptoms: Intestinal Amebiasis symptoms: Diarrhea or dysentery, abdominal pain, cramping , anorexia, Diarrhea or dysentery, abdominal pain, cramping , anorexia, weight loss, chronic fatigueweight loss, chronic fatigue

Flask-like UlcerFlask-like Ulcer

Extra-ntestinalAmebiasisExtra-ntestinalAmebiasis

Pyogenic- Liver AbscessPyogenic- Liver Abscess

Liver abscessLiver abscess

This is an amebic abscess of liver. Abscesses may arise in liver when there is seeding of infection from the bowel, because the infectious agents are carried to the liver from the portal venous circulation.

Laboratory DiagnosisLaboratory Diagnosis Entamoeba histolyticaEntamoeba histolytica must be differentiated from other must be differentiated from other

intestinal protozoa including: intestinal protozoa including: E. coliE. coli, , E. hartmanniE. hartmanni, , E. E. gingivalisgingivalis,……,……

Microscopic identification of cysts and trophozoites in the stool Microscopic identification of cysts and trophozoites in the stool is the common method for diagnosing is the common method for diagnosing E. histolyticaE. histolytica.  This can .  This can be accomplished using:be accomplished using:

Fresh stool: wet mounts and permanently stained preparations Fresh stool: wet mounts and permanently stained preparations (e.g., (e.g.,

trichrome). trichrome). Concentrates from fresh stool: wet mounts, with or without Concentrates from fresh stool: wet mounts, with or without

iodine stain, and permanently stained preparations (e.g., iodine stain, and permanently stained preparations (e.g., trichrome).trichrome).  

TreatmentTreatment Intestinal Amebiasis:Intestinal Amebiasis: **Asymptomatic amebiasis(cyst passer)Asymptomatic amebiasis(cyst passer): : Diloxanide Diloxanide

furoate ( furamide)furoate ( furamide) 500 mg 3 times daily / 10 days500 mg 3 times daily / 10 days **Symptomatic amebiasis ( troph. & cyst):Symptomatic amebiasis ( troph. & cyst): - Iodoquinol , - Iodoquinol ,

650 mg 3 times daily/ 20 days or Metronidazole (Flagyl) , 750 650 mg 3 times daily/ 20 days or Metronidazole (Flagyl) , 750 mg 3 times daily/ 10 daysmg 3 times daily/ 10 days

*Amebic *Amebic colitis: Chloroquine, 250 mg 2 times daily colitis: Chloroquine, 250 mg 2 times daily * Acute amebic dysentery: Emetine hydrochloride, 1mg/kg * Acute amebic dysentery: Emetine hydrochloride, 1mg/kg

daily IM or SCdaily IM or SC

TreatmentTreatment

Extraintestinal AmebiasisExtraintestinal Amebiasis::

**Amebic liver abscess, ameboma: Amebic liver abscess, ameboma: Metronidazole, as above plus Metronidazole, as above plus dehydroemetine / 10 days or Metronidazole or dehydroemetine / 10 days or Metronidazole or dehydroemetine as above plus Chloroquine , dehydroemetine as above plus Chloroquine , 500 mg 2 times daily / 2 days,…..500 mg 2 times daily / 2 days,…..