Viral Pathogensis

Question 1

What are the routes of viral entry

Answer 1

Skin
Respiratory tract
Alimentary tract
Eyes
Urogenital tract
Vertical transmission

Question 2

What is a viremia

Answer 2

Presence of infectious virus particles in the blood

Question 3

Types of viremia

Answer 3

Primary Viremia: progeny virions are released into blood after initial replication at the site of entry. VIRAL LOAD IS DECREASED

Secondary viremia: subsequent viral replication results often extensive virus particles

Question 4

How does the organ invasion occur

Answer 4

By 3 types of blood-tissue junctions
1- Capillary
2- Venule
3-Sinusoid

Question 5

Which viruses invade organs from Skin

Answer 5

Varicella-zoster

Question 6

What are the host control mechanisms for viral spread

Answer 6

1- Early Non-Immune Control: type 1 ınterferons , NK cells ,complement system, proteolytic cleavage
2- Immune Control— humoral and cellular

Question 7

What are types of virus-host cell interactions

Answer 7

A) permissive host cell : support viral replication
B) abortive infection : no infectious progeny virus
C) persistent infection: Latent I., Chronic I., Slow I.

Question 8

Latent infection

Answer 8

Poorly recognized by the immune system
Viral genome persists intact so that productive infection can be initiated to spread infection to new hosts.

Question 9

Which viruses do Latent infection in non-replicating DNA in a non-dividing cell

Answer 9

HSV
VZV in neurons

Question 10

Which viruses do autonomous self-replicating DNA in dividing cell

Answer 10

EBV
CMV
HPV
HBV
KSHV

Question 11

Which viruses integrated into host chromosome, replicated with host

Answer 11

HHV6

Question 12

What is the role of Type 1 Interferons in viral pathogenesis

Answer 12

Limit the ability of viruses moving to neighboring cells
Produced by infected cells
Regulate and limit viral infections

Question 13

In which type of virus-host cell interactions DNA or RNA tumor viruses may convert a normal cell into a malignant one

Answer 13

Transforming Infections
HPV
HBV
HHV-8
EBV
HTLV1
HCV

Question 14

What is Tissue Tropism

Answer 14

Viral affinity for specific body tissues determined by cell receptors for virus , cell transcription factors that recognize viral promoters and enhancer sequences LTR or HIV, ability of the cell to support virus replication

Question 15

What is the Host Cell receptor for HIV

Answer 15

CD4
CCR5

Question 16

What are the host cell receptor for COVID19

Answer 16

ACE2
TMPRS2

Question 17

What are the host cell receptors for Rabies

Answer 17

Acetylcholine receptor

Question 18

What are the host cell receptors for HSV

Answer 18

Heparin sulfate

Question 19

Viral virulence?

Answer 19

Capacity of a virus to cause a disease in the host

Question 20

Viral virulence influenced by

Answer 20

Dose
Route of administration
Age
Sex
Susceptibility of the host

Question 21

What are the viral gene products that modify host defense

Answer 21

Immune modulators
Apoptosis
Autophagy
Intrinsic proteins
Vitokines and viroceptors
Complement binding proteins
Modifiers of MHC 1,2 pathways

Question 22

For pregnancy which viruses are more lethal

Answer 22

Hepatitis A,B,E,
Influenza
COVID-19

Question 23

What are the non-specific immunity molecules in pathological response

Answer 23

Phagocytosis cells (neutrophils, macrophages)
Cytokines (interferons)
NK cells

Question 24

What are the specific immunity molecules in immune pathological response

Answer 24

Ag specific B and T cell responses
Ab
Cytotoxic T cells
Ab dependent cellular toxicity