Diagnostic Parasitology

Question 1

Techniques in the diagnosis of parasitic infections

Answer 1

Diagnostic parasitology

Question 2

Formula for 10% formalin

Answer 2

10/100 * 1000

Question 3

Common Reagents

Answer 3

Carbol Fuchsin
Formalin (5% and 10%)
Lugol’s Solution
SAF

Question 4

An acid-fast stain

Answer 4

Carbol Fuchsin

Question 5

Reagent used for Cryptosporidium spp. and in general for Coccidian parasite (group)

Answer 5

Carbol Fuchsin

Question 6

Reagent used for preservation of protozoan CYST

For all-purpose use

Answer 6

5% Formalin

Question 7

Reagent used for helminth eggs, larvae and adult stage

Answer 7

10% formalin

Question 8

Stain for parasite

the first stain to be developed

Answer 8

Lugol’s solution

Question 9

Regaent used as substitute for Schaudinn’s solution

Does not have mercuric chloride

Answer 9

Sodium acetate-acetic acid formalin fixative

Question 10

Also called routine fecal analysis

Answer 10

Direct fecal smear

Question 11

simplest and easiest technique to facilitate detection of intestinal parasites

Answer 11

Direct Fecal smear / Routine fecal analysis

Question 12

Detects the presence of intestinal protozoans (trophozoites or cyst) or helminth eggs can be observed directly with a light microscope

Answer 12

DFS / routine fecal smear

Question 13

vegetative, motile, and labile stage of parastie

Answer 13

Trophozoite

Labile means easily killed

Question 14

Trophozoites are processed within

Answer 14

30mins - 1hr

Question 15

Trophozoites are usually found in what type of stool

Answer 15

Water stool

Question 16

Nonmotile and resistant stage of parasite

Answer 16

Cyst

Question 17

Stage of parasite that can survive in harsh environment

Answer 17

Cystr

Question 18

Cyst is seen in what type of stool

Answer 18

Formed stool

Question 19

In preparation of DFS

Answer 19

small amount of fresh feces is mixed with either

Saline (NSS) - to detect protozoan motility

Lugol’s/Iodine solution - to reveal the parasite structure
- however no live parasite can be seen here as it is toxic

Question 20

Reagent that is toxic for parasite and only used to reveal structure/morphology

Answer 20

Lugol’s solution/iodine solution

Question 21

Seen when using Saline preparation

Answer 21

Motile trophozoites and larvae
RBCs (must be reported)
Leukocytes
Charcot Leyden crystals (reported)

Question 22

Seen when using Iodine preparation

Answer 22

Cysts of protozoa

Question 23

DFS PREPARATION

Answer 23

Place 1 drop of NSS and 1 drop of Lugol’s/iodine on separate places

Take 2mg of fecal specimen (by poking the specimen with applicator stick)

Emulsify in the drop of saline

next using different stick 2mg of stool emulsify in drop of iodine (which will kill any organisms present)

Place a coverslip there should be no air bubbles

Question 24

Reading DFS slide

Answer 24

Systematic reading should be enforced

read the whole cover slip

Question 25

Disadvantage of DFS

Answer 25

has lower sensitivity | can't detect parasites most of the time especially if the person has low parasitemia or parasitic infection

Question 26

technique used for monitoring large-scale treatment programmes implemented for the control of soil-transmitted helminth infections

Answer 26

Kato Katz Technique

Question 27

o Commonly used in the community to determine if the treatment was successful

Answer 27

Kato katz

Question 28

Parasites acquired from the soil

Answer 28

soil-transmitted helminths

Question 29

what are the soil-transmitted helminths

Answer 29

Ascaris lumbricoides Trichuris trichiura Hookworm Threadworm

Question 30

o Quantify eggs and establishes burden of intestinal infection (worm burden)

Answer 30

Kato katz

Question 31

A quantitative technique

Answer 31

KAto katz can quantify the number of eggs How many / the concentration of parasites in the body

Question 32

Manner of reporting in kato katz

Answer 32

Eggs per gram stool (epg)

Question 33

Technique that can Quantify eggs and establishes burden of intestinal infection

Answer 33

Kato katz

Question 34

Materials and reagents for kato katz

Answer 34

``` Wooden applicator stick Screen Template Plastic spatula Microscope slides Hydrophilic cellophane Flat bottom jar with lid Newspaper, absorbent tissue Glycerol-malachite green ```

Question 35

Kato katz template

Answer 35

Used to measure the stool 9mm on a 1mm thick template : 50mg 6mm on a 1.5mm thick template : 41.7mg 6.5 on a 0.5mm thick template : 20mg

Question 36

Glycerol-malachite green reagent

Answer 36

Glycerol = clearing agent Malachite green = stain Where hydrophilic cellophane is soaked

Question 37

Hydrophilic cellophane

Answer 37

soaked in glycerol-malachite green used as the cover slip

Question 38

Screen

Answer 38

Used to sieve the stool

Question 39

KATO KATZ technique can be used for

Answer 39

Parasites with thick eggshell EXCEPT for hookworm because hookworm eggs are cleared rapidly due to think eggshell which is why important to read slide immediately

Question 40

EXCEPT for hookworm how many hours should kato katz slides be stored

Answer 40

1 or more hours To speed up the clearing and examination, slide can be plced in a 40 degrees incubator or kept in direct sunlight for several minutes

Question 41

A. Lumbricoides and T. trichiura in Kato katz technoque

Answer 41

since they have thick eggshells, slides can remain visible for many monts

Question 42

Hookworm eggs in Kato katz technique

Answer 42

since they have thin eggshells they can only remain visible for 30-60mins

Question 43

Schistosome eggs (Blood fluke) OR Cercaria (Infective stage) in Kato katz

Answer 43

recognizable for up to several months bUT is recommended to be examined within 24 hours

Question 44

Technique used for Enterobius vermicularis (pinworm) and Taenia solium/Taenia saginata

Answer 44

Cellophane swab

Question 45

Extreme itchiness of the perianal area

Answer 45

enterobiasis

Question 46

Pork tapeworm

Answer 46

Taenia solium

Question 47

Beef tapeworm

Answer 47

Taenia Saginata

Question 48

Time of collection for cellophane swab (Enterobius vermicularis)

Answer 48

Early in the morning before the person washes or defecates

Question 49

Caused by tapeworm - Taenia solium / Taenia saginata

Answer 49

Taeniasis

Question 50

How many negative tests to rule out pinworm infection

Answer 50

5 times negative (Daily)

Question 51

Pinworm becomes infective for how many hours

Answer 51

4-6 hours

Question 52

Mode of transmission of Enterobius vermicularis

Answer 52

INHALATION

Question 53

The egg of enterobius vermicularis is usually

Answer 53

D-shaped

Question 54

REagent to apply after using cellophane swab

Answer 54

Toluol or I2 in xylol

Question 55

procedures allow for the detection of parasitic elements (eggs, larvae, oocysts, and cysts) that may be missed when examining only a direct wet smear. More sensitive than DFS HOWEVER there will be no live parasites because will be killed by formalin

Answer 55

Concentration technique More stool = more sensitive

Question 56

(under concentration technique) parasite will sink; parasite found at the bottom

Answer 56

Sedimentation

Question 57

(under concentration technique) parasite will float; parasite at the top

Answer 57

Floatation

Question 58

Also called concentration technique

Answer 58

Formalin-ethyl acetate sedimentation concentration ``` Formalin = preservative Ethyl-acetate = dissolve fats ```

Question 59

recommended as being the easiest to perform and the least subject to technical error, allowing recovery of the broadest range of parasitic elements. The specimen can be fresh or fixed stool.

Answer 59

Formalin-ethyl acetate sedimentation concentration

Question 60

This technique is not recommended for eggs of | Fasciola spp. and larvae of Strongyloides stercoralis

Answer 60

Formalin-ethyl acetate sedimentation concentration

Question 61

This procedure leads to recovery of all protozoan cysts and oocysts, helminth eggs and larvae present in the stool specimen;

Answer 61

Formalin-ethyl acetate sedimentation concentration

Question 62

separation of parasitic elements from the coarsest organic debris, using a high specific density flotation solution.

Answer 62

concentration by floatation

Question 63

most widely used flotation solution

Answer 63

zinc sulfate solution and sodium chloride