PRL UNIT 3 Flashcards by EJ E

Motility of trophozoites is best demonstrated using Logol’s iodine. (True or False)

False

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Improper placement of coverslip often leads to the formation of air bubbles in the fecal smear. ( True or False)

True

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Identify: What reagent acts as a clearing agent in the Kato-Katz preparation?

Glycerol

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Identify: Currently, what is considered as the gold standard for the diagnosis of Malaria?

Thick and Thin Smear

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Identify: What is the specimen of choice for the diagnosis of pinworm infections?

Cellophane Swab / Scotch Tape Swab

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Detects organisms that have lipid content in
their cell walls or membrane

Carbol Fuchsin

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AFS is for what coccidian parasites

C - Cryptosporidium
C - Cyclospora
C - Cystoisospora belli

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CARBOL FUCHSIN

Preservation of protozoan cysts

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LUGOL’S IODINE / SOLUTION

Temporary stain for cyst

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METHYLENE BLUE

Temporary stain for protozoan trophozoites

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SODIUM ACETATE ACETIC ACID FORMALIN FIXATIVE SAF

Substitute for Schaudinn’s solution; below the standard of Schaudinn’s

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also be called direct wet mount or direct wet preparation

Direct Fecal Smear

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simplest and easiest technique to facilitate detection of intestinal parasites that infected
subjects pass in their feces

Direct Fecal Smear

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What are present under DFS

Presence of intestinal protozoa (trophozoites or
cyst) or helminth eggs

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Reason why saline is used in DFS

to detect protozoa motility

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Reason why Lugol / Iodine solution is used in DFS

to reveal the parasite structure

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% NaCl used in DFS

0.85% NaCl motility

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Seen in Saline preparation

Motile trophozoites and larvae
Red blood cells
Leukocytes
Charcot - Leyden crystals

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Seen in Iodine preparation

Cysts of protozoa
- structures which would help identify the specific protozoa found within the specimen

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mg of fecal specimen used in DFS

2mg

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cause of iodine to trophozoites

iodine will kill any organisms present; thus, no motility will be seen

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manner of observation DFS

Up-down direction
Left-right direction

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Kato-Katz Technique

Recommended for monitoring large-scale
treatment programmes implemented for the
control of soil-transmitted helminth STH

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common STH found using Kato Katz

Hookworm
Ascaris Lumbricoides
Trichuris Trichiura
Schistosoma

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Manner of reporting KK Technique

eggs per gram stool (epg)

purpose of KK Technique

- Can identify the intensity of the infection - Correlate to severity of clinical disease with the intensity of infection / worm burden

Feces Delivered when size of hole is 9mm

50 mg of feces

Feces Delivered when size of hole is 6.5 mm

about 20 mg of feces

reason for using same size templates

used to ensure repeatability and comparability of prevalence and intensity data

unique material used in KK technique

Glycerol-malachite green

used as a dye and staining solution

Malachite green

acts as a clearing agent

Glycerol

hrs cellophane is dipped

at least 24 hours

(T/F) No cover slip; cellophane will serve as the cover slip

For all except ___, keep the slide for one or more hours at room temperature to clear the fecal material prior to examination under the microscope.

hookworm eggs

done to speed up clearing and examination

slide can be placed in a 40C incubator or kept in direct sunlight for several minutes.

Will remain visible and recognizable for many months

A. lumbricoides T. trichiura eggs

Clear rapidly and will no longer be visible after 30-60 mins

Hookworm eggs

May be recognizable up to several months but it is preferable to examine the slide preparations within 24 hours

Schistosome eggs

EPG

1. x 20 if using a 50 mg template; 9mm and 1mm thick 2. x 24 if using a 41.7 mg template; 6mm and 1.5mm thick 3. x 50 if using a 20 mg template; 6.5mm and 0.5 thick

Ascaris Lumbricoides Intensity Infections

L - 1 - 4,999 epg M - 5,000 - 49,999 epg H - ≥ 50,000 epg

Trichuris trichiura Intensity Infections

L - 1 - 999 epg M - 1,000 - 9,999 epg H - ≥ 10,000 epg

Hookworms Intensity Infections

L - 1-1,999 epg M - 2,000 - 3,999 epg H - ≥ 4000 epg

Schistosoma mansoni Intensity Infections

L - 1 - 99 epg M - 100 - 399 epg H - ≥ 400 epg

Gold standard for malaria diagnosis

Thick and Thin Smear

Difference of Thick and Thin Smear

Thick - Used to determine if parasite is present; for screening Thin - Used to confirm the Plasmodium species present; for confirmatory testing, fixed with methanol

specimen used for Thick and Thin Smear

finger prick / capillary puncture

Blood Parasites that can be detected using Thick and Thin Smear

Plasmodium, Babesia, Hemoflaggelates, Trypanosoma Leishmania, Filarial nematodes

Done with thick smears

dipped in water to dehemoglobinize

smear that's more blood sensitive

Thick blood smear

type of test malarial parasites are considered as

Quantifying

used to quantify malaria parasites against RBCs by counting the parasitized RBCs among 500-2000 RBCs on thin smear and express results as %

Parasitemia

if parasitemia is high

examine 500 RBCs

if parasitemia is low

examine 2,000 RBCs (or more)

other terms for Cellophane Swab

Perianal swab, Scotchtape swab, Cellophane tape swab

Cellophane swab

Specimen of choice for the detection of Enterobius vermicularis (pinworm) eggs

Enterobiasis

caused by a nematode, Enterobius vermicularis

Taeniasis

caused by tapeworm, Taenia solium or Taenia saginata

pinworms

Enterobius vermicularis

why are Enterobius vermicularis called nocturnal parasites

At night, when the body is at rest gravid pregnant adult female worms exit the host, typically a child, through the rectum and lay numerous eggs in the perianal region

Time of Collection for Cellophane Swab

early in the morning before the patient washes or defecates

reason why time of collection is important for cellophane swab

it creates a better yield and catch the eggs within the specimen

number of negative tests to rule out pinworm infection

MOT of Enterobius vermicularis

fecal-oral, inhalation

Itching of perianal area

Pruritus Ani

importance of emphasizing the importance of exercising proper hygiene and preventive measures

to avoid spreading infectious eggs into the environment

concentration technique commonly used

Formalin-ethyl acetate sedimentation technique (FEACT & FECT)

applicable to all parasites

Sedimentation

Interested in the sediments we obtained; area has concentrated parasitic structures

Sedimentation

Concentration

- detects small number of parasites - remove debris - used to fresh and preserved samples

recommended as being the easiest to perform and the least subject to technical error

Formalin-ethyl Acetate Sedimentation Concentration

recovery of a ll protozoan cysts and oocysts, helminth eggs, and larvae present in the stool specimen

Formalin-ethyl Acetate Sedimentation Concentration

Difference in technique for : 1. Sedimentation 2. Flotation

1. Sedimentation - examine sediment; lower specific gravity than parasite 2. Flotation - examine surface; higher specific gravity to float

used for heavy eggs

Sedimentation

used for light eggs

Flotation

These procedures allow for the detection of parasitic elements (eggs, larvae, oocysts and cysts) that may be missed when examining only a direct wet smear

Concentration Techniques

rises to the top of the suspension during sedimentation

Eggs, cysts, and oocysts

4 contents of test tubes for concentration techniques

1. sediment 2. saline 3. plug of faecal debris 4. top layer of ethyl acetate

most widely used floatation solutions

Saturated sodium chloride & Zinc sulfate

Harada Mori Filterpaper Culture

uses stool streaks and detects Filariform L3 Larva

Specific Gravity of 1. Saturated Sodium chloride 2. Zinc sulfate

1. NaCl - 1.20 2. ZnSO2, 7H2O - 1.35

(T/F) Higher specific gravity, the more parasites that can be concentrated

Baermann Funnel Culture

uses cheesecloth and larva attached to water and detects Filariform L3 Larva

can diagnose Filariform L3 Larva

Hookworm, Strongyloides

Knott's Concentration Technique

blood concentration technique; and for low counts

Sheather's Flotation Technique

used to detect coccidians oocysts

Concentration Techniques

1. Brine Flotation Technique 2. McMaster Concentration Technique 3. Mini-FLOTAC Technique

Rapid Diagnostic Test for Malaria

for concentration techniques

Circumoval Precipitin Test (COPT) Schistosoma

for detection of Schistosoma

Sabin-Feldman Dye Test

for detection of Toxoplasma gondi trophozoites

reagent used in the unstained portion of the DFS

NSS

stage of protozoan may not be recognized in the stained portion of the DFS

Trophozoite

Preferably, the amount of stool needed to be emulsified in the preparation of direct fecal smear.

2 mg

Which eggs clear rapidly and will no longer be visible after 30–60 mins in a Kato-Katz smear

Hookworm eggs

Gold standard in the diagnosis of malarial parasite

Thick and thin smear

acts as a clearing agent in a Kato-Katz smear

Glycerol

Which among the following diagnostic test helps establish burden of intestinal infection?

Kato-Katz

In malarial parasite diagnosis, which part of the smear is used for species differentiation?

thick smear

Multiple ring forms observed in a single red cell. This is typical for _____?

Plasmodium falciparum

To rule out pinworm infection, the # of negative scotch tape swabs must be _____:

Technique for : Entamoeba histolytica trophozoite

DFS (unstained)

Technique for : Enterobius vermicuris eggs

Cellophane swab

Technique for : Plasmodium vivax schizont

Thick and Thin smear

Technique for : Burden of intestinal ascariasis

Kato-Katz

Technique for : Entamoeba histolytica cyst

FEACT