INTESTINAL AMOEBA, FLAGELLATES AND CILIATES – DR. GELLA PARASITE SIZE RANGE Entamoeba histolytica PARASITE BIOLOGY TROPHOZOITE PARAMETERS 8 – 65 um à average 12 – 25 um 8 – 22 um à average 12 – 18 um MOTILITY / SHAPE NUMBER OF NUCLEI KARYOSOME PERIPHERAL CHROMATIN CYTOPLASM progressive, finger-like pseudopodia 1 small + central fine + evenly distributed finely granular CYTOPLASMIC INCLUSIONS ingested RBCs (bluish black color in IH) spherical à round 1–4 small + central fine + evenly distributed finely granular ** young cyst - chromatoid bars with rounded ends - diffuse glycogen mass VIRULENCE FACTORS (1) N-galactosamine à surface galactose binding (2) Lectin à mediates binding to host cells + contribute to amebic resistance to complement (3) Amebapores à small peptides capable of lysing cells = role in killing intestinal epithelial cells, hepatocytes + host defense cells (4) Cysteine proteinases à key role in tissue invasion, evasion of host defenses + parasite induction of gut inflammation TRANSMISSION CYST SPECTRUM OF DISEASE *ASYMPTOMATIC CARRIER STATE - low-virulence strain - inoculation into host = low - Px immune system = intact **SYMPTOMATIC INTESTINAL (1) Amebic colitis à flask-shaped colon ulcers (2) Amebic dysentery à blood + mucus in stool (3) Secondary bacterial infection ***SYMPTOMATIC EXTRAINTESTINAL (1) weakness, weight loss, sweating, pronounced nausea, vomiting (2) migrate + infect the lung, pericardium, spleen, skin + brain - Amebic pneumonitis - Venereal amebiasis = penile amebiasis from a woman with vaginal amebiasis - Liver abscess = most COMMON à posterosuperior aspect of the right lobe - Fecal-oral route - Food preparation (contaminated by poor hygiene - Human waste (for crop fertilization) - Oral-anal sex EXCYSTATION small + large intestine HABITAT cecum LABORATORY DIAGNOSIS (1) wet mount + permanent staining techniques (2) culture à TYI-33 = supports growth of amoeba (3) E. histolytica stool antigen testing (preferred) - test sensitivity = 87% - test specificity = >90% (4) OTHER TESTS: - Fecal leukocytes (+) - Occult blood (+) - Fecal eosinophilia (Charcot-Leyden crystals) - Antigen tests à ELISA, IHA, GDP + IIF TREATMENT (1) Tissue Amebicides - act on organisms in the bowel wall + liver - e.g., chloroquine, emetines, metronidazole, tinidazole (2) Luminal Amebicides - act ONLY in the lumen of the bowel - e.g., diloxanide furoate, iodoquinol + paromomycin PARASITE PARASITE BIOLOGY PARAMETERS SIZE RANGE Entamoeba hartmanni MOTILITY / SHAPE NUMBER OF NUCLEI KARYOSOME PERIPHERAL CHROMATIN CYTOPLASM CYTOPLASMIC INCLUSIONS PARASITE CYST 5 - 15 um à average 8 – 12 um 5 – 12 um à average 7 – 9 um nonprogressive, finger-like pseudopodia 1 small + central fine + evenly distributed finely granular spherical 4 (quadrinucleated) small + central fine + evenly distributed finely granular ** young cyst - chromatoid bars with rounded ends - diffuse glycogen mass ingested bacteria PARASITE BIOLOGY PARAMETERS SIZE RANGE Entamoeba coli TROPHOZOITE MOTILITY / SHAPE NUMBER OF NUCLEI KARYOSOME PERIPHERAL CHROMATIN CYTOPLASM CYTOPLASMIC INCLUSIONS TROPHOZOITE CYST 12 - 55 um à average 18 – 27 um 8 – 35 um à average 12 – 25 um nonprogressive, blunt pseudopodia 1 large, irregular shape + eccentric unevenly distributed coarse + granulated round à spherical 8 large, irregular shape + eccentric unevenly distributed coarse + granulated ** young cyst - chromatoid bars with pointed to splintered ends - diffuse glycogen mass à may displace nuclei to opposite ends of the cyst (seen in cysts with 2 nuclei) vacuoles containing bacteria (often visible) PARASITE PARASITE BIOLOGY PARAMETERS SIZE RANGE Entamoeba polecki MOTILITY / SHAPE NUMBER OF NUCLEI KARYOSOME PERIPHERAL CHROMATIN CYTOPLASM CYTOPLASMIC INCLUSIONS PARASITE MOTILITY / SHAPE NUMBER OF NUCLEI KARYOSOME PERIPHERAL CHROMATIN CYTOPLASM CYTOPLASMIC INCLUSIONS CYST 8 - 25 um à average 12 – 20 um 10 – 20 um à average 12 – 18 um NORMAL STOOLS: sluggish, nonprogressive DIARREIC STOOLS: progressive, unidirectional 1 (consistent) small + central fine + evenly distributed granular + vacuolated ingested bacteria + other food particles spherical or oval 1 small + central fine + evenly distributed granular ** young cyst - chromatoid bars with angular or pointed ends - glycogen mass PARASITE BIOLOGY TROPHOZOITE ONLY!!! PARAMETERS SIZE RANGE Endolimax nana TROPHOZOITE 5 - 12 um à average 7 – 10 um sluggish, nonprogressive, blunt pseudopods 1 large, irregular, blot-like ABSENT granular + vacuolated ingested bacteria PARASITE PARASITE BIOLOGY PARAMETERS SIZE RANGE Iodamoeba butschlii MOTILITY / SHAPE NUMBER OF NUCLEI KARYOSOME PERIPHERAL CHROMATIN CYTOPLASM CYTOPLASMIC INCLUSIONS PARASITE MOTILITY / SHAPE NUMBER OF NUCLEI KARYOSOME PERIPHERAL CHROMATIN CYTOPLASM CYTOPLASMIC INCLUSIONS CYST 4 - 22 um à average 12 – 18 um 4 – 12 um à typically 7 – 10 um sluggish, progressive 1 large, usually central refractive achromatic granules à may or may not be present ABSENT coarsely granular + vacuolated spherical or oval 1 (uninucleated) ingested bacteria, yeast cells + other debris large glycogen body -> stains deeply with iodine large, blot-like, usually central ABSENT granular + vacuolated PARASITE BIOLOGY TROPHOZOITE ONLY!!! PARAMETERS SIZE RANGE Entamoeba gingivalis TROPHOZOITE 8 - 20 um active, varying pseudopod appearance 1 centrally located fine + evenly distributed finely granular ingested epithelial cells + bacteria PARASITE BIOLOGY PARASITE PARAMETERS SIZE RANGE SHAPE Balantidium coli SURFACE MOTILITY INFECTIOUS REPRODUCTION NUCLEI IMPORTANT CELL STRUCTURES DIAGNOSIS HABITAT lumen of large intestines SPECTRUM OF DISEASE penetrate into the mucosa layer àcause ulcers TROPHOZOITE CYST 50 – 130 mm (long) x 20 – 70 mm (wide) 40 – 60 mm across oval, pointed at anterior end spherical covered with thick, hard cyst wall with cilia sometimes visible underneath non-motile YES ✓ non-reproductive only macronucleus (kidney-shaped) visible *young cysts à contractile vacuole visible **older cysts à organelle structures look granular covered in cilia rotary or boring motility à “like a thrown football” NO ✘ binary fission or conjugation macronucleus (kidney-shaped) + micronucleus (spherical, next to macronucleus) visible funnel-shaped cytostome (cell mouth) near anterior end + 2 contractile vacuoles found in feces + tissue biopsies of infected individuals VIRULENCE FACTOR Hyaluronidase à enzyme = to penetrate into the mucosa layer cyst wall à 1 or 2 layers found in feces of infected individuals TREATMENT (1) Tetracyclines à 500mg, 4x a day for 10 days (2) Metronidazole à 750mg, 3x a day for 5 days *Iodoquinol à 640mg, 3x a day for 20 days **If NOT TREATED à persistent diarrhea = high fluid loss + dehydration ***If ABDOMINAL BLEEDING occurs à death EPIDEMIOLOGY 1% global prevalence = humans 20 – 100% prevalence = pigs PREVENTION - proper sanitation - safe water supply - protection of food from contamination PARASITE SIZE RANGE SHAPE MOTILITY Giardia intestinalis Giardia lamblia Giardia duodenalis Lamblia intestinalis FORMER NAME: Cercomonas intestinalis PARASITE BIOLOGY TROPHOZOITE PARAMETERS 8-20 um ling, 5-16 um wide 8-17 um long, 6-10 um wide pear-shaped, teardrop ovoid falling leaf APPEARANCE bilaterally symmetrical NUMBER OF NUCLEI 2 ovoid-shaped à each with a large karyosome NO peripheral chromatin CYTOPLASM FLAGELLA immature cyst = 2 mature cyst = 4 central karyosomes NO peripheral chromatin retracted from the cell wall 4 pairs à origination of each: 1 pair = anterior end 1 pair = posterior end 1 pair = ventral end 1 pair = caudal end 2 median bodies OTHER axostyle à for support STRUCTURES sucking disk à for attachment PATHOGENESIS CYST INCUBATION PERIOD = 1-4 weeks (9 days) MILD – MODERATE INFECTIONS - cramping + diarrheic stools - excessive flatus with H2S odor - abdominal bloating, nausea + anorexia SEVERE / CHRONIC INFECTIONS - malabsorption in the gut (steatorrhea) - inflammation of mucosa + hyperplasia of lymphoid follicles - weight loss, body malaise, chills + low grade fever LABORATORY DIAGNOSTICS DFS Zinc-sulfate floatation technique Duodeno-jeunal aspiration Entero test (6-8 hours) ELISA TREATMENT median bodies interior flagellar structures Metronidazole Quinacrine Furazolidone Acrasil PARASITE NOTES Dientamoeba fragilis - NOT AN AMOEBA à intestinal flagellate - almost always found solely as a trophozoite - TRANSMISSION + PATHOGENICITY = poorly understood PARASITE NOTES SIZE RANGE 5-18 um SHAPE MOTILITY NUMBER OF NUCLEI CYTOPLASM irregularly round progressive, broad hyaline pseudopodia 2 à each consisting of massed clumps of 4-8 chromatin granules NO peripheral chromatin bacteria-filled vacuoles à 2 pairs (central + extending laterally) PARASITE SHAPE - nonpathogenic flagellate à often described as a commensal organism in the human GI tract - lives in the cecal region on the colon - has a well-defined trophozoite + cystic stage NOTES MOTILITY NUMBER OF NUCLEI FLAGELLA - exist only in trophozoite stage - human commensal (GIT) CYST 5-25 um long, 5-10 um wide 5-10 um long pear-shaped lemon-shaped à with a clear hyaline knob extending from the anterior end stiff, rotary, directional 1 à with small central or eccentric karyosome NO peripheral chromatin 4 à 3 = extending from anterior end + 1 = extending posteriorly from the cytostome region 1 à with large central karyosome NO peripheral chromatin CYTOPLASM retracted from cell wall prominent cytostome à extending 1/3 to ½ body OTHER length STRUCTURES spiral groove well-defined cytostome à located on 1 side of the nucleus PARASITE BIOLOGY TROPHOZOITE ONLY!!! PARAMETERS SIZE RANGE Pentatrichomonas hominis PARASITE BIOLOGY TROPHOZOITE PARAMETERS SIZE RANGE Chilomastix mesnili PARASITE BIOLOGY TROPHOZOITE ONLY!!! PARAMETERS MOTILITY NUMBER OF NUCLEI FLAGELLA OTHER STRUCTURES 7-20 um long, 5-18 um wide jerky / jittery 1 à with small central karyosome NO peripheral chromatin 3-5 anterior flagella axostyle à extends beyond the posterior end of the body undulating membrane à full body length PARASITE NOTES Trichomonas tenax - exist only in trophozoite stage - found in oral cavity PARASITE NOTES SIZE RANGE 5-14 um long MOTILITY NUMBER OF NUCLEI FLAGELLA OTHER STRUCTURES jerky / jittery - exist only in trophozoite stage - HABITAT à vagina + prostate gland (prefers slightly alkaline environment or somewhat more acid than that of healthy vagina) - in MALES à can be demonstrated in the urine, urethral discharge or following massage of the prostate 1 ovoid 5 à 4 = extend anteriorly + 1 = extends posteriorly undulating membrane à 2/3 body length PARASITE BIOLOGY TROPHOZOITE ONLY!!! PARAMETERS SIZE RANGE Trichomonas vaginalis PARASITE BIOLOGY TROPHOZOITE ONLY!!! PARAMETERS up to 30 um long SPECTRUM OF DISEASE DISEASE: Trichomoniasis - vaginitis à purulent discharge (prominent symptom) + vulvar and cervical lesions, abdominal pain, dysuria + dyspareunia INCUBATION PERIOD = 5-28 days SHAPE MOTILITY NUMBER OF NUCLEI CYTOPLASM FLAGELLA ovoid, round, pear-shaped stiff, rotary, directional 1 ovoid remarkable large amount of siderophile granules 3-5 = extending anteriorly 1 = extending posteriorly OTHER undulating membrane à 1/2 body length STRUCTURES in MEN à frequently asymptomatic - urethritis, epididymitis + prostatitis (occasionally) DIAGNOSIS Demonstration of trophozoite in à sedimented urine, vagina secretions + scrapings, prostatic secretions TREATMENT Metronidazole Douche of vinegar / lactic acid
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