Entamoeba histolytica

1. Entamoeba histolytica
MANOJMAHATO

2. CHARACTERISTICS OF PROTOZOA
1. Protozoa are unicellular eukaryotic organism
2.Single cell perform the all the function
3.size vary from 2-150 µ
4. locomotion by pseudopodia, flagellae or cilia
5.Nucleus may be compact with diffuse central DNA and peripheral RNA.
6. Respiration anaerobic.
7.secrete digestive enzymes, toxins, cytolysin and antigenic substances.
8. Reproduction: may be asexual or sexual.

3. CONTENTS
 General character
 Classification
 Introduction
 Morphology
 Life cycle
 Pathogenesis
 Intestinal amoebiasis
 Clinical features
 Extraintestinal amoebiasis
 Diagnosis
 Treatment
 Prevention

4. GENERALCHARACTEROFENTAMOEBAHYSTOLYTICA:
 Unicellular, Eukaryotic
 Found in damp habitat
 Microscopic organism
 Single cell perform the all the function.
 locomotion by pseudopodia
 Respiration anaerobic
 Reproduction: may be asexual or sexual.
 Secrete digestive histolysin enzymes

6. CLASSIFICATION
Phylum :- Sarcomastigophora
Subphylum :- Sarcodina
Superclass:-Rhizopoda
Class:- Lobosea
Orders:- Euamoebida
Genus:- Entamoeba
Species:-histolytica

7. INTRODUCTION
 Entamoeba histolytica causes amoebasis
 First described by Losch in 1875 after being isolated in Russia
from a patient with dysenteric stool
Geographical distribution
 World wide distribution – 3rd after malaria and schistosomiasis
 Worldwide amoebiasis causes 40,000-100,000 deaths every
year

8. EPIDEMIOLOGY
 0.5 to 50% of the population world wide harbors E. histolytica
 Higher rates of infection in underdeveloped countries.
 Infectaion is associated with poor hygiene.
 Humans are the principal host, although dogs, cats and rodents may be
infected.
 The word histolytic literally means "Tissue destroyer“

9. HABITAT
Large intestine of man : Trophozite Forms : Mucous and submucous layer
MORPHOLOGY
The parasite exists in three morphological forms:
Tropozoite
Precyst
Cyst
TROPOZOITE PRECYST CYST

10. Trophozite
 15-30 in diameter
 Active, feeding stage,Growing stage
 Motile ,Amoeboid with blunt pseudopodia
 Non-infective stage
 Food vacuoles: RBCs, leucocytes and tissue debris
 Found in intestinal & extra-intestinal lesions diarrhoeal stools

11. Entamoeba histolytica TROPHOZOITES

12. PRECYST:-
 Smaller in size
 10-20µm in diameter
 Oval with a blunt pseudopodium
 Food vacuoles disappear
 Characteristics nucleus

13. CYST
 Spherical, 1-15 µm in diameter
 Surrounded by a thick chitinous wall
 Uni nucleated → Bi nucleated → tetra nucleated
 Cyst are present only in the lumen of the colon
and in formed faeces
 Infective form for humans
 Mature cyst has 4 nuclei (diagnostic feature)
 Not killed by chlorination
 Readily killed by boiling or filtration of water

14. Cysts of Entamoeba histolytica
 GHI
IHG
Cysts of Entamoeba histolytica /, permanent
preparations stained with trichrome.

15. LIFE CYCLE
InfectionInfection
Infection occurs by ingestion of cysts on fecally contaminated food or hands.

16. PATHOGENESIS
Ingestion of cysts
Excystation in
small intestine
Production of 8
trophozoites
Multiplication
and Colonization
in large intestine
Tissue
invasion and
destruction
Flask – shaped
ulcers(mostly in
caecum,
transverse and
sigmoid colon
Encystation
and exit from
host in the
stool
Migrate via
Blood stream(
portal
circulation) to
the liver Amoebic liver
abscess

17. PATHOGENICITY
MODE OF TRANSMISSION:
-Feco-Oral Route: By Ingestion of contaminated food and Drinking water
ROUTE OF TRANSMISSION:
-Fecal-oral route
-By contaminated food & water
 Sources of infection – carriers (asymptomatic & convalescent), houseflies, cockroaches
 Risks – poverty, lack of hygiene, poor sanitation, mental retardation, male homosexuals
INTESTINAL AMOEBIASIS :
 Intestinal amoebiasis indicate that organism are confined to gastrointestinal tract.
 Incubation period :1-4 weeks
 The amoebae invade the colonic mucosa , producing characteristic ulcerative flask shaped
lesions and a profuse bloody diarrhea ( amoebic dysentery)

18. EXTRA INTESTINAL AMOEBIASIS:-
 About 5% individuals
 1. Hepatic amoebasis: Acute Liver Abscess: Develop after 1-3 Months
 Transmit through portal veins from intestine to Liver
Pus of liver abscess: Anchovy Sauce appearance: Contain few Pus cells
liver abscess

19. 2. Pulmonary Amoebiasis: Transmitted from Liver and develop pulmonary Lesions
3.Cerebral Amoebiasis: Transmitted from Liver to heart then Brain and develop cerebral lesion
Cerebral Amoebiasis

20. SIGN AND SYMPTOMS
 Mild symptoms include:
 Loose stools/diarrhoea, including slimy diarrhoea with pus (which is often
foul smelling) and painful passage of stools (tenesmus)
 Stomach pain
 Stomach cramps (colic)
 Nausea

21. SIGN AND SYMPTOMS
 SEVERE SYMPTOMS INCLUDE:
 Liver abscess
 Severe ulceration
 Severe gastric distention of the bowel
 Peritonitis (inflammation of the intestinal wall and its lining) or colitis (inflammation of the
colon, specifically)
 Megacolon (very rare, in 0.5% of the cases)
 Ameboma (which results from formation of annular colonic granulation tissue and may mimic
carcinoma of the colon

22. LABORATORY DIAGNOSIS:
Lab diagnosis is include,
 Parasitic diagnosis
 Sero diagnosis
 Biochemical diagnosis
 Radio imaging diagnosis

23. PARASITIC DIAGNOSIS:
 It includes stool examination
 .

25. STOOL EXAMINATION :
(Formed stools contain cysts & diarrheal stools contain trophozoites)
 Wet mount in saline, Iodine-stained, or fixed trichrome stained preparation
 For motile trophozoites, stools should be examined within 1 hour.Trophozoite of E.
histolytica is differentiated from other amoeba (E.coli) by:
i. Nucleus of trophozoite
For cysts, at least 3 samples should be collected.
i. Size of cyst & number of its nuclei. (Newly formed cyst has 2 nuclei, glycogen mass &
chromidial bars)

27. MICROSCOPIC OBSEVATION

28. OBSERVATION

29. SERO DIAGNOSIS:
 Sero diagnosis by indirect heamaglutination [IHA], indirect fluorescent
agglutination [IFA], [ELISA]

30. Radio imaging Diagnosis
 It’s by ultrasound CT, Scan

31. TREATMENT OF AMEBIASIS :-
 Eradication of amoeba by use of amoebicide on the basis of amoebic site

32. AMOEBICIDE PEDIATRIC DOSE ADULT DOSE
Metronidazole 35-50 mg/kg/day for 7-10 days( in 3
divided doses)
750 mg 8 hourly
Tinidazole 50 mg/kg/day for 3 days(once daily) 2 g once a day
Paromomycin 25-35mg/kg/day for 7 days(in 3 divided
doses)
25-35mg/kg/day (in 3 divided
doses)
Diloxanide furoate 20mg/kg/day for 7 days(in 3 divided doses) 500mg 8 hourly
Iodoquinone 30-40mg/kg/day for 20 days(in 3 divided
doses)
650mg 8 hourly
DRUGS AND DOSES

33. PREVENTION & CONTROL
Primary prevention
 Safe excreta disposal
 Safe water supply
 Hygiene
 Health education
 Treat symptomatic carriers
 Treat water
Secondary
 Early diagnosis
 Treatment

34. PREVENTION & CONTROL

36. COMPRISION BETWEEN AMOEBIC AND BACILLARY DYSENTERY
symptoms Amoebic dysentery Bacillary dysentery
Occurrence Usu. In the form of sporadic cases Usu. In the form of outbreaks
Onset gradual Acute
Fever Usu. Low grade (may be high in
case of liver abscess)
High grade
Tenesmus/Abd. Cramps Moderate Very severe
Stool Foul- smelling Not foul-smelling
RBCs In clumps Discrete
Pus cells Scanty Numerous
Eosinophils Present Absent or rare
Bacteria Numerous, motile Scanty, non-motile
E. histolytica Trophozoites + Absent