1. A MEBIASIS & G IARDIOSIS

2. A MEBIASIS

3. A MEBIAS P ATHOGENS Intestinals Entamoeba histolytica Tisulares (Amebas of Libra) Acanthamoeba Naegleria

4. A MEBIAS I NTESTINALS Entamoeba E.histolytica (pathogen) E. coli E. hartmani E. gingivalis (oral) Endolimax nana Iodamoeba butschlii

5. A MEBIC D YSENTERY Causal agent: Entamobea histolytica is well recognized as a pathogenic amoeba. Geographic Distribution: Worldwide, with higher incidence of amebiasis in developing countries. In industrialized countries, risk groups include male homosexuals, travelers and recent immigrants, and institutionalized populations. History : Loosh was first described in 1875

6. M ORPHOLOGY Different form of E. histolytica; 1- Trophozoite 2- Precyst 3- Cyst(1, 2, 4 nuclei)

7. T ROPHOZOITE CHARACTER Size : 12-60 μm in diameter ; Non-invasive form ( minuta) / E. dispare Invasive form (magna) contain RBC, E. histolytica Pseudopodia Motility Ectoplasm Endoplasm : may be contain ingested RBC Nucleoplasm Non-invasive form invasive form

8. D IFFERENT FORM OF E. HISTOLYTICA CYST

9. L IFE CYCLE Life cycle

10. E PIDEMIOLOGY Prevalence of amebic infection varies with level of sanitation and generally higher in tropics and subtropics than in tempearate climates. *Worldwide prevalence is about 10% to 50% *Cyst passers are important source of infection The true estimated prevalence of E. histolytica is close to 1% worldwide. Entamoeba histolytica is the second leading cause of mortality due to parasitic disease in humans. (The first being malaria). Amebiasis is the cause of an estimated 50,000-100,000 deaths each year.

11. T RANSMISSION 1-Direct contact of person to person ( fecal-oral). 2- Veneral transmission among homosexual males ( oral-anal). 3- Food or drink contaminated with feces containing the E.his. Cyst. 4- Use of human feces (night soil) for soil fertilizer. 5- Contamination of foodstuffs by flies, and possibly cockroaches.

12. P ATHOGENESIS Effective factores: 1- strain virulence 2- susceptibility of the host; nutrition status, immune- sys. 3- breakdown of immunologic barrier (tissue invasion)

13. P ATHOGENICITY MECHANISMS 1- secreting proteolytic enzymes( histolysine ) and cytotoxic substances. 2 - contact-dependent cell killing 3 – cytophagocytosis Amebic killing target cell: 1- receptore-mediated adherence of amebae to target cell ( adherence lectin) 2- amebic cytolysis of target cell 3- amebic phagocytosis of killed target cell

15. C LINICAL SYMPTOMS (2-6 W AFTER INGESTION ) Asymptomatic infection Symptomatic infection Intestinal Amebiasis Extraintestinal Amebiasis Dysenteric (40% Fever) Non-Dysenteric colitis Hepatic Pulmonary(R) The extra foci(p,p,b) (Fulminant,perfuration Toxic megacolon) Liver abscces Acute nonsupprative Intestinal Amebiasis symptoms: Diarrhea or dysentery,Lower abdominal pain, cramping, anorexia, weight loss, chronic fatigue

17. P ATHOLOGY OF A MEBIASIS

18. F LASK - LIKE U LCER

19. E XTRA - I NTESTINAL A MEBIASIS

21. 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.

22. D IAGNOSIS Paraclinical Diagnosis: Sigmoidoscopic examination: precence of a grossly normal mucosa between the ulcers serves to differentiate amebic from bacillary dysentery,( the entire mucosa being involvoed in bacillary dysentery). Hepatomegally C.B.C. : leukocytosis in Amebic dys. rises above 12000 per microliter, but counts may reach 16000 to 20000 per microliter.

23. L ABORATORY D IAGNOSIS Entamoeba histolytica must be differentiated from other intestinal protozoa including: E. coli, E. hartmanni, E. dispare,…… Differentiation is possible, but not always easy, based on morphologic characteristics of the cysts and trophozoites. The nonpathogenic Entamoeba dispar, however, is morphologically identical to E. histolytica, and differentiation must be based on isoenzymatic or immunologic analysis. Molecular methods are also useful in distinguishing between E. histolytica and E. dispar and can also be used to identify E. polecki.

24. M ICROSCOPY Microscopic identification This can be accomplished using: Fresh stool: wet mounts and permanently stained preparations (e.g., trichrome). Concentrates from fresh stool: wet mounts, with or without iodine stain, and permanently stained preparations (e.g., trichrome).

25. T ROPHOZOITES OF E NTAMOEBA HISTOLYTICA / E. DISPAR ( TRICHROME STAIN ) Microscopy A B In the absence of erythrophagocytosis, the pathogenic E. histolytica is morphologically indistinguishable from the nonpathogenic E. dispar! Each trophozoite has a single nucleus, which has a centrally placed karyosome and uniformly distributed peripheral chromatin.

26. T ROPHOZOITES OF E NTAMOEBA HISTOLYTICA WITH INGESTED ERYTHROCYTES ( TRICHROME STAIN ) The ingested erythrocytes appear as dark inclusions. Erythrophagocytosis is the only morphologic characteristic that can be used to differentiate E. histolytica from the nonpathogenic E. dispar. FE

27. C YSTS OF E NTAMOEBA HISTOLYTICA / E. DISPAR GHI IHG Cysts of Entamoeba histolytica/E. dispar, permanent preparations stained with trichrome.

28. I MMUNODIAGNOSIS 1- Antibody detection : The indirect hemagglutination (IHA) The EIZA test detects antibody specific for E. histolytica in approximately 95% of patients with extraintestinal amebiasis, 70% of patients with active intestinal infection, and 10% of asymptomatic persons who are passing cysts of E. histolytica.

29. 2- Antigen detection may be useful as an adjunct to microscopic diagnosis in detecting parasites and to distinguish between pathogenic and nonpathogenic infections. Recent studies indicate improved sensitivity and specificity of fecal antigen assays with the use of monoclonal antibodies which can distinguish between E. histolytica and E. dispar infections.

30. M OLECULAR DIAGNOSIS In reference diagnosis laboratories, stool PCR is the method of choice for discriminating between the pathogenic species ( E. histolytica) from the (nonpathogenic species ( E. dispar.

31. T REATMENT Amebic Colitis or Liver Abscess: Tinidazole: Better tolerate & more effective for: colitis and liver abscess(2 gr.3d) Metronidazol: Parenteral available (750 mg tid po or IV 5- 10d) Entamoeba histolytica Luminal Infection: Paromomycin: 30mg/kg tid po 5-7 d Idoquinol: 650 mg tid po 20d

32. Giardia lamblia Source: http://soils.cses.vt.edu

33. The genus Giardia belongs to the class Zoomastigophorea, the order Diplomonadida, and the family Hexamitidae. It is one of the most primitive eukaryotes: it has a small subunit ribosomal RNA sequence and no mitochondria and Golgi apparatus Now Giardia can be classified according to antigen, isoenzyme, and genetic analysis in addition to their morphology and host range.

34. Species identified Giardia lamblia (intestinalis, duodenalis) - humans, mammals Giardia muris - mammals Giardia ardeae - birds Giardia psittaci - birds Giardia agilis - amphibians

35. Of the Giardia species, only G. lamblia has been successfully cultured in vitro. The trophozoite divides by longitudinal binary fission Two morphological forms: Trophozoite and cyst ( infective form)

36. Tear drop shaped 2 adhesive discs, 2 median bodies, 2 nuclei 4 pairs of flagella Source: www.sd01.k12.id.us

37. Tear drop shaped 2 adhesive discs, 2 median bodies, 2 nuclei 4 pairs of flagella Source: www.sd01.k12.id.us

38. intracytoplasmic projections axonemes Source: http://medlib.med.utah.edu

39. Haematoxilyn staining two nuclei, each with a prominent central karyosome (characteristic facelike image ) Source: Gallery of histology Woods and Ellis2000

40. 8 to 12 mm long and 7 to 10 mm wide convex dorsal surface a flat ventral surface sucking or adhesive disk four pairs flagellae Source: http://soils.cses.vt.edu

41. Epidemiology Host can be humans, primates, cats, dogs, calves, beavers, rabbits, etc. World wide distribution Highest incidence in children, young adults in late summer.

42. Transmission 1- Person to person transmission 2- Water sports, surface contamination. Watershed contamination 3- sexually active male homosexuals and persons in custodial institutions.

43. Pathogenesis and Immune response (1) The production of diarrhea, and occasionally malabsorption, is the result of a complex interaction of Giardia with the host, Infection occurs after oral ingestion of as few as 10 to 25 cysts. After excystation, trophozoites colonize and multiply in the upper small bowel Adherence of G. lamblia in the human gut may be via the disk, but may also involve specific receptor-ligand interactions

44. Pathogenesis and Immune response (2) Several pathogenic mechanisms have been postulated Disruption of the brush border Mucosal invasion Elaboration of an enterotoxin Stimulation of an inflammatory infiltration leading to fluid and electrolyte secretion and occasionally to villous changes

45. TEM micrograph showing the method of attachment to the duodenal wall. Ventral sucking disc Source: Gallery of histology Woods and Ellis2000

46. Immune Response Partially protective immunity may develop to Giardia Immune response involves both cellular and humoral immunity - Ig A, serum Ig G and Ig M are detected in patients: role of Ig A is not completely understood, probably inhibits trophozoite attachment - IgA deficiency lead to chronic giardiasis - Cell mediated immune response may also play a role Human milk may also play a role in protection of the host against Giardia : Free fatty acids and IgA antibodies

47. Infection with G. lamblia includes 1- Asymptomatic cyst passage (5 to 15% ) acute self-limited diarrhea (25 to 50% ) and a chronic syndrome of diarrhea malabsorption, and weight loss 2- Symptomatic giardiasis is characterized by acute onset of diarrhea, abdominal cramps, bloating, and flatulence feelings of malaise, nausea, and anorexia may complain of sulfuric belching Vomiting, fever, and tenesmus occur less commonly. stools may be profuse and watery, but later they are commonly greasy, and foul-smelling and may float

48. The role that chronic infection with Giardia plays in the growth and development of children in the developing world has been controversial

49. Life Cycle Trophozoites : Lives in duodenum, jejenum and upper ileum They come in close contact to the mucosal, but do not invade the host. Adhesive disc fits over surface of epithelial cell The flagella act as a pump to move nutrients away from the microvilla and hold the adhesive disc near the mucosa. Rapid division to produce large numbers quickly

51. Source: Doug Allington

52. 14 billion parasites in diarrheic stool (trophozoites only) Moderate infection: 300 million cysts. As the organism traverses the colon it is stimulated to encyst. Produce an oval cyst with thick walls, with 2-4 nuclei. Dividing within cyst (4 nuclei is older cyst) Complete division in duodenum of host after ingestion Cyst is approximately 8-10m and ellipsoid in shape. The cyst is the infective state and is transferred by the fecal-oral route.

53. Diagnosis Giardia should be identified 50 to 70% of the time after one stool, and 90% identification after three stools Wet, saline mounts: falling leaf motion, fibrils present, and nucleic characteristics. Biopsy tissue/duodenal aspirate stained by trichrome or Giemsa stain. Enzyme immunoassay and fluorescent-anitbody monoclonal antigen detection systems Sensitivity & specificity: 90-100% ( ProSpec T, GiardEIA, MeriFluor, Color Vue, and DD System)

54. Source: http://soils.cses.vt.edu

55. Source: Doug Allington

57. Source: http://www. cbc.ca

58. Drugs Dose Metronidazole250mgtidX 5-7 d Nitazoxanide500mg bdX3d Paromomycin 25–30 mg/kg/d in 3 doses × 5–10 d Tinidazole 2 g × 1 dose

59. PREVENTION The prevention of giardiasis requires proper handling and treatment of water Good personal hygiene on an individual basis Chlorination alone is sufficient to kill G. lamblia cysts, important variables, such as water temperature, clarity, pH, and contact time, alter the efficacy of chlorine, and higher chlorine levels (4 to 6 mg/liter) may be required. Bringing water to a boil is sufficient to kill all protozoal cysts; at high altitudes, boiling for longer periods may be necessary

60. Artistic impression by Russel Kightley Source: http://soils.cses.vt.edu