Practical 5: Virology

Question 1

Why is that the laboratory is notified in advance of a viral agent?

Answer 1

They are notified ahead of time, if the viral agent is going to cause harm to the laboratory workers

Question 2

Why are viruses considered with certain times of the year?

Answer 2

Because some viruses are seasonal

Question 3

What are the different types of methods for viral collection?

Mnemonic 
4 Bs
2 Ss
1 U
1 T
1 R
1 N

Answer 3

a) Nasal swabs
b) Bronchial washes
c) Rectal or stool specimens
d) Urine
e) Skin and mucous membrane
f) Body fluids
g) Blood
h) Bone Marrow
i) Tissue
j) Serum

Question 4

Why is the specimen for the suspected viral agent collected immediately?

Answer 4

This is because the presence of the virus disappears after 2 days after the symptoms

Question 5

Principles of nasopharyngeal swabs

Answer 5

• Used for the detection of respiratory syncytium

- Used for influenzae and para-influenzae

Question 6

Principles for bronchial washes?

Answer 6

• Used for the collection of lower respiratory tract infections

Question 7

Principles for rectal swabs?

Answer 7

• Used to detect rotaviruses, enteric adenoviruses and enteroviruses

Question 8

Principles for urine collection?

Answer 8

• Increase in viral recovery when processed in multiples
• Best urine sample is morning urine
• Used to detect CMV, rubella, measles, mumps, polyomaviruses and adenoviruses

Question 9

Principles for skin and mucosal lesions collection?

Answer 9

• Used to detect Herpes Simplex virus
• Used to detect Varicella Zoster Virus
• Uses vesicular lesions
• Collection requires use of Tzanck smear