LE1 (Laboratory Safety, Microscopes, Principles of Kato-Katz and FECT)

Question 1

What level is a laboratory of parasitology generally classified at? (WHO, 2019)

Answer 1

Basic Biosafety 2 Laboratory (BSL-2)

Question 2

Parasitology Laboratories are designed for 3 objectives, which are?

Answer 2

Education, Diagnosis, and Research

Question 3

Name the 3 most commonly used disinfectants (WHO, 2019)

Answer 3

1. Sodium hypochlorite (Bleach)
2. 70% ethanol or isopropanol
3. Quaternary ammonium compounds

Question 4

Regarding handling specimens, microscopic slides should be discarded into a pot containing what solution?

Answer 4

1% Hypochlorite Solution

Question 5

What’s the risk group number of most of the parasites?

Answer 5

Risk Group 02

Question 6

Indicate the magnification and color of each objective lens of the compound microscope.

Answer 6

4x (Red)
10x (Yellow)
40x (Blue)
100x (White)

Question 7

What lens/magnification do you use to search for eggs and larvae of helminths?

Answer 7

Low Power Objective (10x Magnification)

Question 8

What lens/magnification do you use to search for most protozoans?

Answer 8

High Power Objective (40x Magnification)

Question 9

What is the value of the stage micrometer’s known unit (in mm and um)?

Answer 9

0.01 mm or 10 um

Question 10

What are 2 Types of Blood Samples? Also, indicate how to obtain the two.

Answer 10

Venous Blood - Venipuncture
Capillary Blood - Fingerstick

Question 11

Which finger do you prick in capillary blood smears?

Answer 11

3rd or 4th

Question 12

Enumerate the steps in Staining Blood Smear according to Humanson (1972)

Answer 12

1. Air dry thin blood smear
2. Dip prepared smears on a coplin jar with methanol for one minute
3. Remove slides from methanol and transfer to Giemsa stock solution for 30 minutes
4. Slides were dipped consecutively on two coplin jars with tap water
5. Blot dry with tissue gently and air dry

Question 13

How do you properly treat a human blood sample? (Solution used and time)

Answer 13

10% Bleach Solution for 30 minutes

Question 14

Cysts and Trophozoites are commonly found in what type of stool?

Answer 14

Cysts: Formed Stool
Trophozoites: Diarrheal Stool

Question 15

If stool kits are unavailable, the specimen should be divided and stored in 2 different preservatives. Which are they?

Answer 15

10% Formalin
PVA (polyvinyl-alcohol)

Question 16

Among different stool specimens (Stool with Blood and Mucus, Formed Stool, and Diarrheal Stool), what is the order of priority?

Answer 16

1. Stool with Blood and Mucus
2. Diarrheal Stool
3. Formed Stool

Question 17

Complete the Principle behind the FECT:

1. The preservation of the sample with _____,
2. Removal of lipid material with _____, and
3. Sedimentation through _____.
4. The _____ is then examined under the microscope for protozoan cysts and helminth eggs.

Answer 17

1. Formalin
2. Ether
3. Centrifugation
4. sediment

Question 18

True or False:

The Kato-Katz technique is used for qualitative diagnosis only, not semi-quantitative.

Answer 18

False, it’s used for both

Question 19

What level of STH transmission rate is recommended for the Kato-Katz technique?

Answer 19

Moderate to High Transmission Rates

Question 20

True or False:

People infected with STH or intestinal schistosomes pass the eggs of the worms through their sputum.

Answer 20

False, it’s through their feces, not sputum

Question 21

What’s the purpose of soaking the cellophane in glycerol using the Kato-Katz technique?

Answer 21

The glycerol clears the fecal material from around the eggs. The eggs are then counted and the number calculated per gram of feces (epg)