Parasitology Part 3 Flashcards

Question

***_Enteromonas hominis_***

Answer 1

* Found in warm or temperate climates * **Both trophozoite and cyst forms** * Infection acquired through the ingestion of cysts, in fecal contaminated food or water * **Resides in the large intestine, is regarded as commensal** * Cysts may resemble those of E. nana cysts with **1-4 nuclei having central karyosome without** **peripheral chromatin** * 4 flagella; 3 anteriorly and one posterior * Cytosome not visible

Answer 2

* Found in warm or temperate climates * Infection acquired through the ingestion of cysts, **in fecal contaminated food or water** * Resides in the large intestine, is regarded as a **commensal** * **Both trophozoite and cyst form** * 2 anterior flagella in trophozoite * One nucleus with small central karyosome and a fine ring of chromatin granules * Cytosome extending up to half body length starting in the anterior end * **Cysts (4-7 µm long) in a stool specimen, stained with trichrome** * Trophozoites (4-10 µm long) in a stool specimen, stained with trichrome * In the large intestine, excystation releases trophozoites

Answer 3

* In the gastrointestinal tract (cecum/ colon) of humans * **Closely related to Trichomonas spp.** * T**rophozoites only, lack external flagella, move by sluggish pseudopodia or by Brownian movement** * **Clover leaf-shaped clumps (disintegrated appearance) of chromatin in the nucleus** * Harder to stain, blend with the background * Cysts have not been identified * May cause dientamoebiasis in institutionalized or MSM * **Known to be transmitted on helminth eggs** * **D. fragilis trophozoites (5-15µm long) stained with trichrome** * **The trophozoite is the only stage found in the stools of infected individuals** * Symptoms/Disease * Mostly asymptomatic in 75% of adults * In 90% of children mostly symptomatic: * intermittent diarrhea * abdominal pain * nausea * anorexia * fatigue * malaise * poor weight gain * Dientamoeba fragilis Diagnosis * **Stained smear is the recommended procedure because no cyst stage exists** * Culture * Antigen, and antibody techniques, are not commercially available * **PCR from fresh unpreserved stool** * ****Epidemiology * Worldwide * Probably transmitted by fecal-oral route and possible transmission via helminth eggs Ascaris, Enterobius * Tends to be common in some pediatric populations * Institutionalized individuals, homosexuals

Answer 4

* Cilia covering the outer cell surface * Key features to look for: * Size, shape, and number of nuclei * Presence of: * Cytostome * Sac like structure * Food vacuoles, ingested bacteria * 1or 2 contractile vacuole * Rotary movement * Row of cilia visible between double wall of cyst

Answer 5

* **Only pathogenic ciliate for humans** * **Is the largest of all the protozoa** * **Both trophozoite and cyst forms** * **Pigs** are the primary reservoir for B. coli * Other reservoirs chimpanzees and monkeys (tropics) * **50-100 X 40-70 um** * Balantidiasis Symptoms * Mostly asymptomatic * Symptomatic infection: * Persistent diarrhea (weeks to months), occasionally dysentery (similar to amebiasis), abdominal pain, tremendous fluid loss, and weight loss * Noninvasive * Severe in debilitated persons * Balantidiasis Diagnosis * Detection of trophozoites in * stool specimens * tissue collected during endoscopy * Cysts less frequently encountered * Passed intermittently and once outside colon rapidly destroyed * Stools collected repeatedly, and immediately examined or preserved * Balantidium coli Epidemiology * Worldwide * Rare in US * Human infection balantidiasis * in warm and temperate climates * sporadically in cooler areas * in institutionalized groups * pig farmers or people in slaughter houses

Answer 6

* Entamoeba histolytica/dispar * Entamoeba hartmanii * Entamoeba coli * Entamoeba polecki * Iodamoeba bütschlii * Endolimax nana

Answer 7

* **Amoeba** – (sometimes amoeba or ameba, plural amoebae) a group of protozoa that moves by means of pseudopods; well-known as a representative unicellular organism * **Amebiasis** – infection with any of various amebae which ranges from chronic, mild diarrhea to fulminating dysentery * **Chromatoidal bodies** – aggregations of ribosomes * **Karyosome** – aggregation of chromatin in the nucleus of a cell not undergoing mitosis

Answer 8

* Pseudopod * Locomotion with contractile vacuole sucks in water and dispels into extending pseudopods * Vacuoles * Feeding * Endocytosis into vacuoles * exocytosis of waste products

Answer 9

* Size * Nucleus * karyosome * peripheral chromatin * Cytoplasm appearance * Inclusions * vacuoles * RBC's

Answer 10

* Size * Shape * Nuclei * Number * karyosome * peripheral chromatin * Cytoplasm * Inclusions * chromatoidal bodies * glycogen vacuole * **7 Nuclei - entameba coli**

Answer 11

* General * Amebic dysentery = bloody diarrhea * Liver abscess * Amoeboma * histo = tissue * lytic = destroy * Transmission * Fecal-oral * contaminated food/water * sexual contact * risk groups * travelers * recent immigrants * institutionalized populations * specific sex practices * Pathways * noninvasive infection * asymptomatic * luminol amebiasis * intestinal disease * diarrhea, dysentery * invasive extraintestinal disease * right upper quadrant pain * fever * Invasive extraintestinal disease * organisms carried by the bloodstream * abscesses spread to other organs * liver most common sites * right upper quadrant pain * fever * Diagnosis * Microscopy * Peripheral chromatin uniformly distributed * Granular or “ground glass” cytoplasm * Trophozoite * **Size: 15-20 μm (range 12-60 μm)** * **Centrally placed karyosome** * **Single nucleus** * **Cyst** * **Size= 12-15um (range 10-20 um)** * **4 karyosome** * Direct exam: stool sigmoidoscopy, biopsy specimens & aspirates * Serologic testing: EIA, IHA, antigen detection (not on formalin-fixed stool) * Culture: From fecal specimens - Robinson's medium, Jones' medium * PCR

Answer 12

* trophozoites only * oral transmission * 10-35um in length

Answer 13

* Trophozoite * Single nucleus with centrally located karyosome, **the bull's eye** * **clean cytoplasm** * **size = 8 to 10 um (5-12 um range)** * cysts * Cytoplasm often clean * Chromatoidal bodies with round ends * **Size: 6 to 8 μm (range 5-10 μm)**

Answer 14

* Trophozoite * single nucleus with large eccentric karyosome * **Size: 20-25 μm (range 15-50 μm)** * Peripheral chromatin clumped or uneven * chromatoidal bodies with splintered ends * Cytoplasm coarse and vacuolated “dirty” ingests debris, vacuoles * Cysts * Chromatoidal bodies with splintered ends * Cytoplasm may be clean * 8 nuclei vary in morphology * **Length: 15 to 25 μm (range 10 to 35 μm)** * cysts that don't stain well * **five nuclei or more confirmation of coli**

Answer 15

* Trophozoite * nucleus with small discrete karyosomal chromatin * even or uneven peripheral chromatin * **size = 15 to 20 um ( 10 to 15 um range)** * cysts * One or rarely two nuclei with eccentric karyosome * **Length: 11 to 15 μm (range 9 to 18 μm)** * Inclusion mass * Red chromatoid bodies

Answer 16

* trophozoite * one nucleus with large central karyosome * refractile achromatic * **Size:12 to 15 μm (range 8 to 20 μm)** * Dirty cytoplasm * cysts * uninucleate * **Length: 10 to 12 μm (range 5 to 20 μm)** * **Single large nucleus with eccentric karyosome** * **Glycogen mass**

Answer 17

* Trophozoite * **Single nucleus with large irregular blot-like centric or eccentric karyosome** * Size: 8 to 10 μm (range 6 to 12 μm) * No peripheral chromatin * Clean cytoplasm * cysts * **4 nuclei with large blot-like karyosome** * **Length: 6-8 μm (range 5 to 10 μm)**

Answer 18

* True stat with blood films or CSF exam * Symptoms * neurological manifestations and behavioral changes * seizures, headaches, and visual impairments * disturbances, stiff neck, and mental state abnormalities * nausea, vomiting, low grade fever, lethargy * cerebellar ataxia, hemiparesis, seizure and coma * CSF not refrigerated

Answer 19

* primary amoebic meningoencephalitis (PAM) * infection introduced far up the nose * 1-9 days after swimming * dead after 5 days of infection

Answer 20

* Brain-Eating amoeba * – flagellate

Answer 21

* keratitis (contaminated contact lens solution)

Answer 22

* Found in: * – Elk and buffalo feces * – Places where farm animals are known to eat * – Soil containing rotting plants * – Fresh water sources * • Only one case of amoebic encephalitis reported wordwide * – Recovered after surgery and medication

Answer 23

* Cryptosporidium parvum/hominis * Cyclospora cayetanensi * Cystoisospora (Isospora) belli * Sarcocystis species * APICOMPLEXAN = complex lifestyle

Answer 24

* Belongs to Phylum Apicomplexa, Class Sporozoa and Sub class Coccidia * Phylum Apicomplexa includes both blood and tissue parasites * Most coccidia, however, are intestinal organisms * Life cycles are complex with both sexual and asexual reproduction phases * Humans can serve as definite host when sexual * reproduction occurs and as intermediate host when asexual reproduction occurs * Immature oocyst has a sporoblast whereas mature one usually has two sporocysts containing sporozoites

Answer 25

* **Fecal Contamination of water** * Outbreaks of cryptosporidiosis have been reported in several countries * C. parvum found in both animals and humans * C. hominis only in humans (common in US) * A waterborne outbreak in Milwaukee (Wisconsin) in 1993, that affected more than 400,000 people * Symptoms * Age and immune status * Immunocompetent and immunodeficient * Immunocompetent * short term * self-limited diarrhea lasting approximately 2 weeks * Immunocompromised: CD4 T cell counts \<200/µl * results in a prolonged, life threatening, cholera-like illness * Procedure * **Examine stool using the routine stool formalin ethyl acetate concentration** * **Use one of the modified acid fast stains** or * The newer immunoassay kit reagents * **Oocyst numbers variable** * **Test multiple stool samples before reporting** * Increased centrifugation speed or time (500 × g , 10 minutes) * Wet mount * **Size measure 4-6 μm** * EIA * Direct FA * **Resistance to Disinfectants** * Transmission * Numerous potential hosts for zoonotic transmission especially waste water runoff particularly from lambs and calves * Direct contact person to person contact (fecal material) * Indirect from laboratory or from contaminated surfaces or raw food or water * Low infectious dose; as few as 10 oocysts * Oocysts are resistant to chlorine and ammonia based disinfectants * More common in summer due to increased recreational water activities * Prevention * Handwashing * Safe sex * Avoid touching farm animals * Avoid pet stools * Wash and cooking food * Avoid drinking water from lakes and streams * Bottle water and other drinks may not be safe

Answer 26

* More common in tropics and sub tropics; endemic in Nepal, Peru, Haiti; outbreaks reported from US, South America, Europe, India * **Modified acid-fast** * Cyclospora Oocyst * Bile and trypsin in small intestine trigger the release of sporozoites which invade epithelial cells * Type 1 meronts (merozoites) infect other intestinal cells and type 2 progress to sexual stage * Once fertilized, zygote develops into an immature oocyst that’s passed in feces * Takes 1-2 weeks to mature to become infective * Appears similar to C. parvum cyst but **is larger, 8 -10 um** * After sporulation (maturation), produces 2 sporocysts with 2 sporozoites each * Wet mount and conventional parasitology stains * **Do not stain with trichrome and iron hematoxylin stains** * Two special stains allow a more reliable diagnosis * Modified acid fast stain * Modified safranin stain

Answer 27

* General * **Infects the epithelial cells of the small intestine** * **Least common of the three intestinal coccidia** * Known as C. belli causing the disease isosporiasis * Worldwide, especially in tropical and subtropical areas * Epidemiology * Infects humans and animals * Infect both adults and children, less frequent than Cryptosporidium * C. belli has also been implicated in traveler s diarrhea * Sexual transmission * Outbreaks in institutionalized groups in the US * More at risk with Hodgkin disease and lymphoblastic leukemia * Symptoms * **Diarrhea**, which lasts (months to years), weight loss, abdominal colic, fever with nonbloody diarrhea * Bowel movements (usually 6-10 per day) * In immunosuppressed patients, infants and children, the diarrhea is severe * Recurrences common after discontinuing treatment (TMS) * **Eosinophilia may be present** * ****Cystoisopora Oocyst * Bile and trypsin in small intestine trigger the release of sporozoites which invade epithelial cells * Oocyst is not immediately infectious when shed in stool * Takes 24-48 hours to mature to become infective * No thin-walled oocyst to cause autoinfection as in case of Cryptosporidium * Immature oocyst has a sporoblast which matures to form 2 sporocysts which are walled bodies containing 4 elongated sporozoites each * **Mature oocyst is 20-30 by 10-19 um** * ****Detection * Modified acid fast stain is used for detection * Do not stain with trichrome and iron hematoxylin stains * Like Cyclospora cyst, it autofluoresce and appears: * Bluish at 365 nm * Bright green at 405 nm * Prevention * Ingestion of food and water contaminated with mature, sporulated oocysts * Sexual transmission * Oocysts are very resistant to environmental conditions and remain viable for months if kept cool and moist * Improve personal hygiene and sanitary conditions

Parasitology Part 3 Flashcards

(52 cards)