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  • Giardia+Entamoeba

    1. 1. Giardia lamblia Dr Kamran Afzal Classified Microbiologist
    2. 2. INTRODUCTION <ul><li>Protozoan parasite </li></ul><ul><li>Worldwide distribution </li></ul><ul><li>Giardia lamblia is a single-celled, bi-nucleated intestinal parasite </li></ul><ul><li>Has trophozoite and cyst phases </li></ul><ul><li>Lives in duodenum and jejunum </li></ul><ul><li>Typically found in lakes, streams, or ponds that have been contaminated by human and other animals </li></ul><ul><li>It causes giardiasis </li></ul>
    3. 3. MORPHOLOGY <ul><li>Two stages </li></ul><ul><li>Trophozoite </li></ul><ul><li>Cyst </li></ul><ul><li>Reproduction </li></ul><ul><li>Binary fission </li></ul>
    4. 4. Trophozoite <ul><li>SHAPE </li></ul><ul><li>Pear shaped </li></ul><ul><li>Tear drop-shaped </li></ul><ul><li>Tennis racket or heart shaped </li></ul><ul><li>SIZE </li></ul><ul><li>Length 10-20um </li></ul><ul><li>Width 5-15um </li></ul><ul><li>Thickness 2-5um </li></ul>
    5. 5. <ul><li>BODY </li></ul><ul><li>Bilaterally symmetrical </li></ul><ul><li>AXOSTYLES </li></ul><ul><li>Two in numbers, seen in midline as vertical lines </li></ul><ul><li>NUCLEI </li></ul><ul><li>Two, one on each side of body </li></ul>
    6. 6. <ul><li>FLAGELLAE </li></ul><ul><li>8 flagellae </li></ul><ul><li>(2 anterior, 2 posterior, 2 ventral, and 2 caudal) </li></ul><ul><li>- all arise from kinetosome </li></ul><ul><li>SUCKING DISCS </li></ul><ul><li>2, Circular in shape </li></ul><ul><li>Situated on ventral surface </li></ul>
    7. 7. Cyst <ul><li>SHAPE </li></ul><ul><li>Oval or ellipsoid </li></ul><ul><li>SIZE </li></ul><ul><li>Length 12um </li></ul><ul><li>Width 8um </li></ul><ul><li>NUCLEI </li></ul><ul><li>Two nuclei in immature cyst </li></ul><ul><li>Four nuclei in mature cyst </li></ul><ul><li>FLAGELLAE AND SUCKING DISCS </li></ul><ul><li>May be seen in cytoplasm </li></ul>Mature cyst
    8. 8. LIFE CYCLE of Giardia lamblia Trophozoites Trophozoites Cysts Mature Cysts Duodenum, upper ileum, gall bladder The lower portion of ileum or colon Contaminated water and food Stool Multiplied by binary fission Diarrhea Outside Outside
    9. 10. HABITAT AND TRANSMISSION <ul><li>Trophozoites </li></ul><ul><li>Colonizes in the intestines of mammals, birds, reptiles and amphibians </li></ul><ul><li>Definitive host is human intestine </li></ul><ul><ul><li>Duodenum and Jejunum </li></ul></ul><ul><li>Cyst </li></ul><ul><li>Contaminated material </li></ul><ul><li>Human colon </li></ul><ul><ul><li>Sigmoid colon </li></ul></ul><ul><li>TRANSMISSION </li></ul><ul><li>Via fecal-oral route </li></ul><ul><li>As few as 10 cysts can cause disease and up to 900 million cysts can be released by an infected individual in one day </li></ul>
    10. 11. Trophozoites are attached to the mucosal surface by sucker, reproduced by binary fission Diarrhea, abdominal pain, bloating, nausea, and vomiting Mechanical blockage of the intestinal mucosa, competition for nutrients, inflammation Histology: shortening of microvilli, elongation of crypts, and damaging the brush border of the absorptive cells G. lamblia inhabits the duodenum, jejunum and upper ileum PATHOGENESIS
    11. 12. PATHOGENESIS AND PATHOLOGY <ul><li>Fat/CHO digestion decreases and causes malabsorption and maldigestion </li></ul><ul><li>Absorption decreases due to villus blunting causing malabsorption </li></ul><ul><li>Malabsorption and maldigestion causes diarrhea </li></ul><ul><li>Physical damage: clubbing of villi; decreases villus-to-crypt ratio; brush borders of cells are irregular </li></ul>
    12. 13. <ul><li>Feeds on mucous that forms in response to irritation </li></ul><ul><li>Also absorbs vitamins and amino acids </li></ul><ul><li>Giardia can also interfere with vitamin/nutrient absorption </li></ul><ul><ul><li>Vitamin A  vision </li></ul></ul><ul><ul><li>Vitamin D  Rickets </li></ul></ul><ul><ul><ul><li>Both of these are due to long standing infections </li></ul></ul></ul>
    13. 14. CLINICAL FEATURES <ul><li>Incubation is 1- 2 weeks </li></ul><ul><li>Onset is gradual </li></ul><ul><li>Symptoms are nausea, vomiting, diarrhea, dehydration, malaise, flatulence, bloating, cramping, low grade fever and steatorrhea </li></ul><ul><li>Sequelae are malabsorption, lactase deficiency, weight loss, fatigue, depression and rarely reactive arthritis </li></ul>
    14. 15. DIAGNOSIS <ul><li>PATHOLOGICAL EXAMINATION </li></ul><ul><li>Fecal examination </li></ul><ul><li>Water-like feces Trophozoites </li></ul><ul><li>Formed feces Cysts </li></ul><ul><li>Duodenal fluid or bile examination </li></ul><ul><li>String test Trophozoites </li></ul>
    15. 16. <ul><li>ELISA/ </li></ul><ul><li>Rapid tests </li></ul><ul><li>IFA </li></ul><ul><li>PCR </li></ul><ul><li>Histopathology </li></ul>
    16. 17. TREATMENT <ul><li>The most common treatment for giardiasis is Metronidazole (Flagyl) for 5-10 days </li></ul><ul><ul><li>It eradicates Giardia in more than 85% of cases </li></ul></ul><ul><li>Furazolidone (Furoxone) for 7-10 days </li></ul><ul><li>Quinacrine is also very effective for treating giardiasis </li></ul><ul><li>Combination therapy also may be effective </li></ul><ul><ul><li>Quinacrine and Metronidazole </li></ul></ul><ul><li>Tinidazole, Secnidazole and Albendazole </li></ul>
    17. 18. PREVENTION <ul><li>Avoid water and food that might be contaminated </li></ul><ul><li>Boil water before drinking, even after filtration </li></ul><ul><li>Do not brush teeth with tap water that may be contaminated </li></ul><ul><li>Do not use ice or drink beverages made from tap water </li></ul><ul><li>Wash hands before eating food </li></ul>
    18. 20. Entamoeba histolytica
    19. 21. INTRODUCTION <ul><li>Protozoan parasite </li></ul><ul><li>Worldwide distribution </li></ul><ul><li>Amoebic colitis and liver abscess </li></ul>
    20. 22. CLASSIFICATION <ul><li>Superclass Rhizopoda </li></ul><ul><li>Subphylum Sarcodina </li></ul><ul><li>Family Entamoebidae </li></ul><ul><li>Order Amoebida </li></ul><ul><li>Class Labosea </li></ul><ul><li>Species Entamoeba </li></ul>
    21. 23. <ul><li> SPECIES </li></ul><ul><li>Entamoeba histolytica Pathogenic </li></ul><ul><li>Entamoeba dispar Non pathogenic group </li></ul><ul><ul><li>E. hartmanni </li></ul></ul><ul><ul><li>E. polecki </li></ul></ul><ul><ul><li>E. coli </li></ul></ul><ul><ul><li>E. gingivalis </li></ul></ul>
    22. 24. MORPHOLOGY <ul><li>TROPHOZOITES </li></ul><ul><li>Size 20-40 µm </li></ul><ul><li>Nucleus Single (4-7 µm) </li></ul><ul><li>Cytoplasm </li></ul><ul><li>Ingested red cells </li></ul><ul><li>Rich in glycogen </li></ul><ul><li>Chromatoid bodies </li></ul><ul><li>Locomotion </li></ul><ul><li>Rapid, gliding, explosive with single pseudopodium </li></ul>
    23. 25. MORPHOLOGY <ul><li>CYSTS </li></ul><ul><li>Shape Spherical </li></ul><ul><li>Size 10-16 µm </li></ul><ul><li>Nuclei Four </li></ul><ul><li>Glycogen vacuole </li></ul><ul><li>Chromatoid bodies </li></ul><ul><li>Killed by desiccation or boiling </li></ul>
    24. 26. EPIDEMIOLOGY <ul><li>Geographic distribution is worldwide </li></ul><ul><li>Second to malaria as cause of death due to parasitic protozoa </li></ul><ul><li>Transmission is Fecal-Oral </li></ul><ul><li>Hosts are humans, cats, dogs and rats </li></ul><ul><li>~10% world population infected </li></ul><ul><li>Prevalence in tropical countries is >30% </li></ul>
    25. 27. <ul><li>10% of infected persons develop invasive disease </li></ul><ul><li>40,000-100,000 deaths annually </li></ul><ul><li>High prevalence in low socio-economic status, overcrowding, poor personal hygiene, no indoor plumbing, immigrants from endemic areas, mentally retarded, promiscuous male homosexuals </li></ul><ul><li>Increased severity in children especially neonates, pregnancy and post-partum states, corticosteroid use, malignancy, malnutrition </li></ul>
    26. 28. LIFE CYCLE CYST Ingestion by humans Excystation in small intestine Encystation in colon Excretion in faeces TROPHOZOITE Asymptomatic colonization Amoebic colitis Liver abscess
    27. 30. VIRULENCE FACTORS <ul><li>GIAP Adherence </li></ul><ul><li>Amebapore Cytolytic </li></ul><ul><li>Proteases Necrosis </li></ul><ul><li>Resistance to complement mediated lysis Trophozoites in liver abscess and colonic lesions are resistant </li></ul>
    28. 31. PATHOGENESIS <ul><li>Invasive </li></ul><ul><li>Mucosal necrosis </li></ul><ul><li>Ulceration </li></ul><ul><li>Dysentery </li></ul><ul><li>Ulcer enlargement </li></ul><ul><li>Colitis </li></ul><ul><li>Peritonitis </li></ul><ul><li>Amoeboma </li></ul><ul><li>Metastasis (Extra-intestinal disease) </li></ul><ul><li>Dissemination via portal vein to liver </li></ul><ul><li>Non-invasive </li></ul><ul><li>Asymptomatic colonization </li></ul><ul><li>Non-dysenteric diarrhea , cramps, abdominal discomfort </li></ul>
    29. 32. HOST IMMUNITY <ul><li>High titers of anti-amoebic antibodies occur by 7th day of illness </li></ul><ul><li>Serum of patients with high titers of anti-amoebic antibodies causes lysis of trophozoites </li></ul><ul><li>Recurrence does not occur after liver abscess and colitis </li></ul><ul><li>Amoebas recovered from liver abscess and colonic lesions are resistant to complement mediated lesions </li></ul>
    30. 33. CLINICAL SYNDROMES <ul><li>INTESTINAL DISEASE </li></ul><ul><li>Asymptomatic infection </li></ul><ul><li>Symptomatic non-invasive infection </li></ul><ul><li>Acute recto-colitis </li></ul><ul><li>Fulminant colitis with perforation </li></ul><ul><li>Toxic megacolon </li></ul><ul><li>Amoeboma </li></ul><ul><li>Perianal ulceration </li></ul><ul><li>EXTRA-INTESTINAL DISEASE </li></ul><ul><li>Liver abscess (via portal vein) </li></ul><ul><li>Peritonitis </li></ul><ul><li>Empyema </li></ul><ul><li>Pericarditis </li></ul><ul><li>Lung abscess </li></ul><ul><li>Brain abscess </li></ul><ul><li>Genito-urinary disease </li></ul>
    31. 34. Colitis is the most common form of disease associated with amoebae
    32. 35. Ulceration can lead to secondary infection and extraintestinal lesions
    33. 36. Extraintestinal amoebiasis
    34. 37. Amoebic liver abscess
    35. 38. LAB DIAGNOSIS <ul><li>Microscopy </li></ul><ul><li>Culture </li></ul><ul><li>Molecular Diagnosis </li></ul><ul><li>Serology </li></ul>
    36. 39. MICROSCOPY <ul><li>Multiple samples are required </li></ul><ul><li>Saline preparation has very low yield </li></ul><ul><li>Endoscopic biopsy/ulcer edge scrapings has high yield </li></ul><ul><li>Stool for hematophagous amoebas/Nuclear morphology </li></ul><ul><li>Trichrome stain </li></ul><ul><li>Iron Hematoxylin stain </li></ul><ul><li>Concentration techniques (Formal-acetate) </li></ul><ul><li>Iodine staining for cysts </li></ul>
    37. 40. CULTURE <ul><li>Sensitive but time consuming </li></ul><ul><li>Multiple samples are not required </li></ul><ul><li>NNN medium </li></ul><ul><li>Does not differentiate between E. histolytica and E. dispar </li></ul><ul><li>Helpful in asymptomatic or chronic infections with low levels of cyst passage </li></ul><ul><li>Useful to evaluate efficacy of cure or existence of infection when the presence or absence of antibodies is not definitive </li></ul>
    38. 41. SEROLOGY <ul><li>Anti-amoebic Antibodies (IgG and IgM) </li></ul><ul><li>Develop only in E. histolytica infections </li></ul><ul><li>High levels occur in 80% acute cases and 90% convalescent cases </li></ul><ul><li>Titers remain high for years, not useful in endemic areas </li></ul><ul><li>ELISA stool antigen </li></ul><ul><li>Rapid and simple </li></ul><ul><li>High sensitivity and specificity </li></ul><ul><li>Can distinguish between E. histolytica and E. dispar </li></ul><ul><li>ELISA serum antigen </li></ul><ul><li>IHA Useful in liver abscess and colitis </li></ul>
    39. 42. MOLECULAR DIAGNOSIS <ul><li>PCR </li></ul><ul><li>High sensitivity and specificity </li></ul><ul><li>Can also detect trophozoites by detecting rRNA genes </li></ul>
    41. 44. TREATMENT <ul><li>E. dispar carriage does not require treatment </li></ul><ul><li>Asymptomatic E. histolytica carriage should be treated </li></ul><ul><li>Intraluminal Infection </li></ul><ul><li>Diloxanide furoate 500mg TDS for 10 days </li></ul><ul><li>Paromomycin </li></ul><ul><li>Iodoquinol </li></ul><ul><li>Symptomatic Amoebiasis </li></ul><ul><li>Metronidazole 750mg TDS for 5-10 days </li></ul><ul><li>Tinidazole, Secnidazole and Albendazole </li></ul>
    42. 45. <ul><li>Extra-intestinal Amoebiasis </li></ul><ul><li>Metronidazole + Paromomycin/Diloxanide furoate </li></ul><ul><li> + Emetine </li></ul><ul><li>Needle Aspiration </li></ul><ul><li>For large abscess </li></ul><ul><li>Open Surgical Drainage </li></ul><ul><li>If needle aspiration is not possible </li></ul><ul><li>Perforation/Peritonitis </li></ul><ul><li>Anti-protozoal drugs + Antibacterial drugs + </li></ul><ul><li>Peritoneal drainage </li></ul>
    43. 46. PREVENTION <ul><li>Adequate water purification </li></ul><ul><li>Low levels of chlorine does not kill cysts </li></ul><ul><li>Boiling of drinking water </li></ul><ul><li>Treating vegetables and fruits with strong detergent soap and then soaking in acetic acid for 5-10 minutes </li></ul><ul><li>Proper waste disposal </li></ul><ul><li>Immunization </li></ul><ul><li>Under trial </li></ul>