AMOEBAE

1. AMOEBAE

2. Entamoeba histolytica Morphologic forms: 1- Active Trophozoite form 2- Cyst form

5. Pathogenesis of Extra-intestinal Amoebiasis

6. Lungs Diaphragm Pericardium Peritoneum Stomach Intestines Inferior vena cava Subphrenic abscess Skin Liver Portal circulation General circulation Brain Spleen Suprarenal Kidney Peritoneum Primary infection in colon Perianal skin Genitals

7. Extraintestinal Amoebiasis

8. Hepatic Amoebiasis • Pathogenesis and pathology E. histolytica trophozoites portal vein pseudopodia amebic liver abscess liver tissue cytolytic enzymes rupture peritonitis

9. Hepatic Amoebiasis • Single abscess, different size , usually at the right lobe of the liver. • Microscopically three zones : • Inner: necrotic material and no amoebae • Intermediate: Degenerated liver cells, RBCs, WBCs • Outer : normal layer of liver cells with trophozoites replicating • Typically pus is thick, chocolate brown, resembling anchovy sauce

10. Pulmonary Amoebiasis • Direct primary infection (emboli in blood circulation) • Secondary infection: direct extension from liver abscess through adhesions in diaphragm. • Single or multiple abscess • Expectoration of reddish-brown sputum is characteristic

11. Cerebral Amoebiasis • Occur from complication of liver and pulmonary amoebiasis. • Causes single or several abscess • Very uncommon

12. Spleen and Cutaneous Amoebiasis • Spleen abscess always seen with liver amoebiasis • Cutaneous amoebiasis seen in perianal site

13. Clinical manifestations • In endemic areas 90% are asymptomatic carriers.

14. Clinical manifestations

15. Amoebic dysentry • Incubation period: long and insidious onset • Symptoms; Local abdominal tenderness over sigmoid colon, caecum or appendix. • Stools frequency 6-8 times a day, with blood and mucus and stool is copius in amount.

16. Amoebic liver abscess • Insidious onset • Associated with fever, sweating abdominal pain. • Liver enlarged, and tender. Gross pathology of amebic abscess of liver. Tube of "chocolate" pus from abscess

17. Diagnosis • Parasitic diagnosis • Culture and Isoenzymes diagnosis • Serodiagnosis • Radio-imaging diagnosis

20. Parasitologic Diagnosis • Microscopy • relied on microscopic examination of protozoan morphology. • factors that adversely affect the results of microscopy • inadequate collection conditions • delayed delivery to the laboratory (motility can cease and trophozoites can lyse within 20 to 30 min) • inadequate number of stool collected

21. Parasitologic Diagnosis contd…. • Macroscopic examination • Microscopic : identification of cysts and trophozoites in the stool is the common method for diagnosing E. histolytica • wet mount préparation: very insensitive method (10%) • stained mount: Lugol’s iodine, Giemsa, methylene blue, iodine- trichrome, modified iron hematoxylin stains.

22. Stool examination • Trophozoites are demonstrated by saline wet mount • They are identified by their unidirectional motility with pseudopodia • Cysts are demonstrated by iodine wet mount Trophozoite Cyst

23. Culture and Isoenzymes • Culture Medium: • Xenic medium: Robinson medium, Diamond TYSGM-9 medium • axenic medium: Diamond TYI-S-33 medium • isoenzyme patterns: • obtained from amebic culture lysates by electrophoresis • Differentiate E. histolytica from E. dispar and E moshkovskii,

24. Antibody Detection • Inability to distinguish past from current infection in endemic areas • Combination with detection of the parasite offers the best approach to diagnosis • Serum antibodies to E. histolytica can be detected in 75 to 85% of patients with symptomatic E. histolytica infection. • Assays used: IHA, ELISA, LA, CIE, CF, IFA

25. Antigen Detection • Antigen-based ELISA kits specific for E. histolytica use monoclonal antibodies • Advantages of Antigen-based ELISA: some of the assays differentiate E. histolytica from E. dispar;

26. Diagnosis: Extraintestinal amoebiasis • Specimens: Stool, Aspirates from liver abscess, sputum, peritoneal aspiration Cutaneous swabs. • Parasitic diagnosis: Demonstration of amoebic trophozoites in aspirated pus or sputum by microscopy or culture is specific diagnosis. • Only 15% of cases of amoebic liver abscess are positive to for trophozoites

27. Serodiagnosis • Immense value in diagnosis of extraintestinal amoebiasis • Antibody detection tests like ELISA, and Indirect haemagglutination tests are commonly done. • Amoebic antibody titre of 1:128 or more is diagnostic of amoebic liver abscess.

28. Antigen detection tests • These are of more value in differentiating recent and past infection. • They are also of prognostic value in chemotherapeutic and surgical treatment.

29. Other tests • Leukocytosis, mild anemia, high ESR • Raised liver enzymes (ALT, AST), serum cholesterol levels. • Radio-diagnosis: • USG abdomen: rapid and sensitive • CT-scan, MRI

30. Symbiotic Amoebae in Human Intestines • Entamoeba coli • Entamoeba hartmanni • Endolimax nana • Iodamoeba bütschlii • Dientamoeba fragilis • Blastocystis hominis

31. Entamoeba coli • Cysts • • 8 nuclei • Chromatid bodies less prominent Trophozoites • broad blunt pseudopodia • small eccentric karyosome • irregular peripheral chromatin

32. Intestinal Amebae