Parasitology :) 165-179

Question 1

What are some substances that will interfere with examination of feces for ova and parasites?

Answer 1

Antibiotics, antiseptics, laxatives, mineral oil, soap, water, and urine

Question 2

How many specimens are usually seen for ova and parasites?

Answer 2

At least three since some parasites are eliminated intermittently

Question 3

Name several preservatives for fecal specimens for ova and parasites.

Answer 3

Polyvinyl alcohol, 10% formalin, SAF, and MIF

Question 4

What is the disadvantage of mercuric chloride-based polyvinyl alcohol?

Answer 4

Because it contain mercury, it is poisonous an requires special handling and disposal.

Question 5

What guidelines should be followed regarding the number and timing of stool for routine O&P testing?

Answer 5

No more than 2 or 3 specimens per patient should be submitted and should not be submitted from patients after the fourth day of hospitalization.

Question 6

What are the recommended time limits for examination of formed, soft, and liquid stool specimens for O and P?

Answer 6

Liquid specimens should be examined within thirty minutes of passage or preserved. Soft within 1 hour and formed within 24 hrs.

Question 7

What 3 examinations are usually performed on fresh stool specimen?

Answer 7

Direct wet prep, concentration, and a permanent stained smear

Question 8

What is the purpose of the saline direct smear in the ova and parasite examination?

Answer 8

It is used to study the motility of trophs

Question 9

What is the consistency of the stool specimen in which trophs are most likely to be found?

Answer 9

A liquid specimen

Question 10

How concentrated should the saline direct smear be in the ova and parasitic examination?

Answer 10

One should be able to read newsprint through it

Question 11

Why is iodine used in the direct smear in the ova and parasite examination?

Answer 11

Iodine stains the cysts and allows visualization of the nuclear structure. Trophy are killed by iodin

Question 12

What is the purpose of the concentration technique in the ova and parasite procedure?

Answer 12

It concentrate the parasites and separates them from the fecal debris so they are easier to find

Question 13

Which concentration technique is most widely used for ova and parasites

Answer 13

The sedimentation method. It is the easiest method and least subject to errors

Question 14

What is the disadvantage of the formalin-ether sedimentation method

Answer 14

Ether must be stored in an explosion-proof refrigerator

Question 15

Which parasites are best diagnosed by a permanent stained smear

Answer 15

Protozoa

Question 16

Name a fixative used for preparation of a permanent smear

Answer 16

Schaudinns

Question 17

Name 2 stains used for permanent stained slides in parasitology

Answer 17

Iron hematoxylin and trichrome

Question 18

Which intestinal ameba is pathogenic for man?

Answer 18

E. histolytica

Question 19

Name an ameba with cigar shaped chromatoidal bodies in the cyst

Answer 19

E. histolytica

Question 20

Name an ameba whose cyst contains up to 8 nuclei

Answer 20

E. coli

Question 21

Name an ameba whose trophy ingests RBCs

Answer 21

E. histolytica

Question 22

Name an ameba whose nucleus has delicate, even, peripheral chromatin and a delicate, central karyosome

Answer 22

E. histolytica

Question 23

Name an ameba whose cyst has a large glycogen vacuole

Answer 23

Iodamoeba butschlii

Question 24

Name an ameba whose cyst has only one nucleus

Answer 24

I. butschlii

Question 25

Which ameba causes granulomatous amebic encephalitis (GAE) and ulcerative keratitis in contact lens wearers

Answer 25

Acanthamoeba

Question 26

Which ameba causes primary amebic meningoencephalitis

Answer 26

N. fowleri

Question 27

Name a flagellate that does not have a cyst

Answer 27

Trichomonas or Dientamoeba

Question 28

Name a flagellate that has a lemon shaped cyst

Answer 28

Chilomastix mesnili

Question 29

Name a flagellate whose troops always have 2 nuclei

Answer 29

Giardia lamblia

Question 30

Name a flagellate that can be seen in a blood smear

Answer 30

Trypanosoma

Question 31

Name a flagellate that can be seen in urethral discharge

Answer 31

Trichomonas vaginalis

Question 32

Name a flagellate which resembles an ameba because its flagella can only be seen with electron microscopy

Answer 32

Dientamoeba fragilis

Question 33

Name a common intestinal protozoan whose trophy usually have 2 nuclei and which does not have a cyst stage

Answer 33

D. fragilis

Question 34

Name a flagellate whose cyst has 2 to 4 nuclei at the anterior end, parabolas bodies, an apostles, and cytoplasm that shrinks away from the cell wall.

Answer 34

Giardia lamblia

Question 35

Name a flagellate that looks like an old man with glasses

Answer 35

G. lamblia

Question 36

Name the most common intestinal protozoan infection in the U.S.

Answer 36

Giardiasis

Question 37

Name a flagellate that can be diagnosed from duodenal aspirates or enterotest capsule

Answer 37

Giardia

Question 38

Name a protozoan that is ciliated and has a large kidney shaped macronucleus and a small micronucleus

Answer 38

Balantidium coli

Question 39

Which is the largest protozoan to infect man

Answer 39

B. coli

Question 40

Which parasites can be found in the blood

Answer 40

Plasmodium, Babesia, Trypanosoma, and microfilariae

Question 41

Name 2 parasites that live inside erythrocytes

Answer 41

Plasomodium and Babesia

Question 42

Name a protozoan that infects reticuloendothelial cells

Answer 42

Leishmania

Question 43

Name the parasite that cause sleeping sickness

Answer 43

Trypanosoma gambiense or T. rhodesiense

Question 44

What causes Chagas disease?

Answer 44

Trypanosoma cruzi

Question 45

Which sporozoan causes malaria?

Answer 45

Plasmodium

Question 46

Which parasite has killed more people worldwide than any other

Answer 46

Plasmodium

Question 47

Name a parasite that require the Anopheles mosquito for its sexual cycle

Answer 47

Plasmodium

Question 48

Which species of Plasmodium is associated with enlarged RBCS

Answer 48

P. vivax and P. ovale

Question 49

Which species of Plasmodium has sausage shaped or crescent shaped gametocytes

Answer 49

P. falciparum

Question 50

Which species of Plasmodium commonly has multiple ring forms within one RBC

Answer 50

P. falciparum

Question 51

Which species of Plasmodium is most malignant

Answer 51

P. falciparum

Question 52

Which species of Plasmodium does one see rings and gametocytes only

Answer 52

P. falciparum

Question 53

Which species of Plasmodium is characterized by band shaped trophs

Answer 53

P. malariae

Question 54

Which species of Plasmodium does one see Schuffner dots

Answer 54

P. vivax and P. ovale

Question 55

Which protozoan can be spread by infective oocysts in cat feces

Answer 55

Toxoplasma gondii

Question 56

Which protozoan can cause neurologic problems if contracted by the fetus after the first trimester

Answer 56

T. gondii

Question 57

Which protozoan is the major cause of encephalitis in AIDS patients

Answer 57

T. gondii

Question 58

How is toxoplasmosis usually diagnosed

Answer 58

Serologic test

Question 59

Name a roundworm that has a barrel shaped egg with a clear plug at either end

Answer 59

Trichuris trichuria, whipworm

Question 60

What is the most common helminth infection in the U.S.

Answer 60

Pinworm E. vermicularis

Question 61

Name a roundworm that is diagnosed by the scotch tape test

Answer 61

E. vermicularis, pinworm

Question 62

When is the best time to collect a scotch tape prep

Answer 62

First thing in the morning before bathing or defecation

Question 63

Name a roundworm whose egg resembles a loaf of Italian bread - flat on one side and rounded on the other.

Answer 63

E. vermicularis

Question 64

Name a nematode whose diagnostic stage is the rhabditiform larva

Answer 64

Strongloides

Question 65

Name the most common helminth infection in the world

Answer 65

Ascaris lumbricoides

Question 66

Roundworm that looks like an earthworm

Answer 66

Ascaris lumbricoides

Question 67

Roundworm that can pass from the anus, nose, or mouth

Answer 67

A. lumbricoides

Question 68

Which intestinal parasite is not diagnosed by an O and P prep

Answer 68

Pinworm, it is ID'd by scotch tape prep

Question 69

Beef tapeworm

Answer 69

Taenia saginata

Question 70

Pork tapeworm

Answer 70

T. solium

Question 71

Fish tapeworm

Answer 71

D. latum

Question 72

Which group of parasites require a snail in its life cycle

Answer 72

Flukes